100161041 - AO Smith

GNS-I-S_ 100161041_ 2000005371_Rev D
Installation & Service Manual
Models: 400 - 2100
WARNING: If the information in these instructions is
not followed exactly, a fire or explosion may result causing
property damage, personal injury or death.
-- Do not store or use gasoline or other flammable vapors and
liquids in the vicinity of this or any other appliance.
-- WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone in your
building.
• Immediately call your gas supplier from a near by phone.
Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire department.
-- Installation and service must be performed by a qualified
installer, service agency, or the gas supplier.
 WARNING:
This manual supplies information for the
installation, operation, and servicing of the
appliance. It is strongly recommended that
this manual and the Genesis Service Manual be
reviewed completely before proceeding with an
installation. Perform steps in the order given.
Failure to comply could result in severe personal
injury, death, or substantial property damage.
Save this manual for future reference.
Contents
HAZARD DEFINITIONS .................................................... 2
PLEASE READ BEFORE PROCEEDING ........................ 3
SAFETY INFORMATION ................................................... 4
THE GENESIS -- HOW IT WORKS................................ 5-7
RATINGS ........................................................................... 8
1. DETERMINE UNIT LOCATION
Location of Unit .................................................................. 9
Recommended Service Clearances.................................. 9
Non-Combustible / Combustible Flooring ........................ 10
Combustion Air Options .............................................. 10-13
2. VENTING
Before You Begin ............................................................. 14
Vent System Options ....................................................... 15
General Venting Information ............................................ 16
Conventional Negative Draft Venting .......................... 17-19
Vertical Vent/Ducted Air .............................................. 20-22
Sidewall/Power Venting .............................................. 23-25
Sidewall/Power Venting/Ducted Air.................................. 26
Direct Vent/Sealed Combustion .................................. 27-30
Outdoor Installation .......................................................... 31
3. GAS CONNECTIONS
Connecting to Gas Supply ............................................... 32
Gas Pressure Test ........................................................... 32
Checking Manifold Gas Pressure .................................... 32
Combination Gas Valves.................................................. 33
Checking Gas Supply Pressure ....................................... 34
4. WATER CONNECTIONS
Inlet & Outlet Connections ............................................... 35
Relief Valve ...................................................................... 35
Heating Unit Installations ............................................ 36-37
5. ELECTRICAL CONNECTIONS
Hot Water Supply Boiler Operating Control Module ........ 38
Line Voltage Connections ................................................ 39
Low Voltage Connections ................................................ 39
External EMS Connection to Terminal Strip .................... 39
Terminal Strip Connection Options ............................. 39-40
Remote Mounting of Sensor ......................................... 40
6. STARTUP
Check for Gas Leaks ....................................................... 41
Check Thermostat Circuit(s) ............................................ 41
Check Vent and Air Piping ............................................... 41
Placing the Hot Water Supply Boiler in Operation ........... 41
Start the Hot Water Supply Boiler .................................... 42
If Hot Water Supply Boiler Does Not Start Correctly ....... 42
Set Hot Water Supply Boiler Temperature ...................... 42
Lighting Instructions ......................................................... 43
7. OPERATING INFORMATION
General............................................................................. 44
User Interface ................................................................... 45
Powering Up the Control .................................................. 46
View Menus ................................................................. 47-48
Errors and Warnings ................................................... 47-49
LED Diagnostic Codes ..................................................... 50
Hot Surface Ignition System ............................................ 51
8. DOMESTIC WATER HEATER APPLICATION
Initial Setup of Maximum Water Flow .............................. 52
Water Chemistry............................................................... 53
Typical Water Heater Application Piping w/Storage
Tank(s) ................................................................... 54-55
Multiple Water Heater Application Piping w/Storage
Tank(s) ................................................................... 56-57
Pump Operation ............................................................... 58
Minimum Water Temperatures (domestic hot water) ....... 59
9. MAINTENANCE.....................................................61-67
10. CONNECTION DIAGRAM .................................... 68-69
11. LADDER DIAGRAM ............................................. 70-71
12. WARRANTY ............................................................... 75
Revision Notes .................................................. Back Cover
Hazard definitions
The following defined terms are used throughout this manual to bring attention to the presence of hazards of various risk
levels or to important information concerning the life of the product.
 DANGER
DANGER indicates an imminently hazardous situation which, if not avoided, will result in death or
serious injury.
WARNING indicates a potentially hazardous situation which, if not avoided, could result in death or
 WARNING serious injury.
CAUTION indicates a potentially hazardous situation which, if not avoided, may result in minor or
 CAUTION moderate injury.
CAUTION
CAUTION used without the safety alert symbol indicates a potentially hazardous situation which, if not
avoided, may result in property damage.
NOTICE
NOTICE indicates special instructions on installation, operation, or maintenance that are important but
not related to personal injury or property damage.
2
Installation & Service Manual
Please read before proceeding
Special instructions
NOTICE
This is a gas appliance and should be installed
by a licensed electrician and/or certified gas
supplier. Service must be performed by a
qualified service installer, service agency or
the gas supplier.
 WARNING If the information in these instructions is
not followed exactly, a fire or explosion may
result causing property damage, personal
injury, or death.

Apply enough water to the combustion chamber
lining to prevent airborne dust.
 Remove the combustion chamber lining from the
appliance and place it in a plastic bag for disposal.
• NIOSH stated First Aid:
Eye: Irrigate immediately.
Breathing: Fresh air.
 WARNING The combustion chamber insulation in this
appliance contains ceramic fiber material.
Ceramic fibers can be converted to cristobalite
in very high temperature applications.
The International Agency for Research on
Cancer (IARC) has concluded, “Crystalline
silica in the form of quartz or cristobalite
from occupational sources is carcinogenic
to humans (Group 1).” Normal operating
temperatures in this appliance are below the
level to convert ceramic fibers to cristobalite.
Abnormal operating conditions would have
to be created to convert the ceramic fibers in
this appliance to cristobalite.
This appliance MUST NOT be installed in
any location where gasoline or flammable
vapors are likely to be present, unless the
installation is such to eliminate the probable
ignition of gasoline or flammable vapors.
Improper
installation,
adjustment,
 WARNING
alteration, service or maintenance can
cause injury or property damage. Refer
to this manual for assistance or additional
information, consult a qualified installer,
service agency or the gas supplier.
Checking equipment –
Upon receiving equipment, check for signs of shipping damage.
Pay particular attention to parts accompanying the appliances
which may show signs of being hit or otherwise being
mishandled. Verify total number of pieces shown on packing
slip with those actually received. In case there is damage or a
shortage, immediately notify the carrier.
Do not use this appliance if any part has
 WARNING
been under water. The possible damage to
a flooded appliance can be extensive and
present numerous safety hazards. Any
appliance that has been under water must
be replaced.
The ceramic fiber material used in this
NOTICE
appliance is an irritant; when handling or
replacing the ceramic materials it is advisable
that the installer follow these safety guides.
REMOVAL OF COMBUSTION CHAMBER LINING OR
BASE PANELS:
 Avoid breathing dust and contact with skin
and eyes.
• Use NIOSH certified dust respirator (N95).
This type of respirator is based on the OSHA
requirements for cristobalite at the time this
document was written.
Other types of
respirators may be needed depending on the job
site conditions. Current NIOSH recommendations
can be found on the NIOSH website at
http://www.cdc.gov/niosh/homepage.html.
NIOSH approved respirators, manufacturers, and
phone numbers are also listed on this website.
• Wear long-sleeved, loose fitting clothing, gloves,
and eye protection.
The ceramic fiber material used in this
appliance is an irritant; when handling
or replacing the ceramic materials it is
advisable that the installer follow these safety
guidelines.
Warranty –
Factory warranty (in this manual) does not apply to units
improperly installed or improperly operated.
Experience has shown that improper installation or system
design, rather than faulty equipment, is the cause of most
operating problems.
1.
Excessive water hardness causing a lime/scale build-up in
the copper tube is not the fault of the equipment and is
not covered under the manufacturer’s warranty (see
Water Treatment and Water Chemistry).
2.
Excessive pitting and erosion on the inside of the copper
tube may be caused by too much water velocity through
the tubes and is not covered by the manufacturer’s
warranty (see Hot Water Supply Boiler Flow Rates and
Temperature Rise for flow requirements).
3
Installation & Service Manual
Please read before proceeding
Safety information
 Owner warning –
The information contained in this manual is intended for use
by qualified professional installers, service technicians, or gas
suppliers.
NOTICE
Consult and follow all local Building and
Fire Regulations and other Safety Codes that
apply to this installation. Consult local gas
utility company to authorize and inspect all
gas and flue connections.
A gas appliance that draws combustion air from the equipment
room where it is installed must have a supply of fresh air
circulating around it during burner operation for proper gas
combustion and proper venting.
 WARNING
Should overheating occur or the gas supply
fail to shut off, do not turn off or disconnect
the electrical supply to the pump. Instead,
shut off the gas supply at a location external
to the appliance.
Prevention of freezing –
Heat exchangers and headers damaged by freezing are not
covered by warranty.
See Section 7, Operating Information - Freeze Protection for
more information.
Codes –
The equipment shall be installed in accordance with those
installation regulations in force in the local area where the
installation is to be made. These shall be carefully followed in all
cases. Authorities having jurisdiction shall be consulted before
installations are made. In the absence of such requirements, the
installation shall conform to the latest edition of the National
Fuel Gas Code, ANSI Z223.1. Where required by the authority
having jurisdiction, the installation must conform to American
Society of Mechanical Engineers Safety Code for Controls and
Safety Devices for Automatically Fired Boilers, ASME CSD-1.
All boilers conform to the latest edition of the ASME Boiler
and Pressure Vessel Code, Section IV. Where required by the
authority having jurisdiction, the installation must comply with
the Canadian Gas Association Code, CAN/CGA-B149.1 and/
or B149.2 and/or local codes. This appliance meets the safe
lighting performance criteria with the gas manifold and control
assembly provided, as specified in the ANSI standards for gasfired hot water boilers, ANSI Z21.13.
4
 WARNING
To minimize the possibility of serious
personal injury, fire or damage to your
unit, never violate the following safety
rules.
1. This unit is only for use with the type of gas indicated on the
rating plate.
2. If you smell gas
• shut off gas supply
• do not try to light any appliance
• do not touch any electrical switch; do not use any phone
in your building
• immediately call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instructions
• if you cannot reach your gas supplier, call the fire
department
3. Hot water supply boilers are heat producing appliances. To
avoid damage or injury, do not store materials against the
appliance or the vent-air intake system. Use proper care
to avoid unnecessary contact (especially children) with the
appliance and vent-air intake components.
4. Never cover your unit, lean anything against it, store trash
or debris near it, stand on it or in any way block the flow of
fresh air to your unit.
5. UNDER NO CIRCUMSTANCES MUST FLAMMABLE
MATERIALS SUCH AS GASOLINE OR PAINT THINNER
BE USED OR STORED IN THE VICINITY OF THIS
APPLIANCE, VENT-AIR INTAKE SYSTEM OR ANY
LOCATION FROM WHICH FUMES COULD REACH
THE APPLIANCE OR VENT-AIR INTAKE SYSTEM.
6. Appliance surfaces become hot during operation. Be careful
not to touch hot surfaces. Keep all adults, children, and
animals away from operation of the hot unit. Severe burns
can occur.
7. You must take adequate care to prevent scald injury when
storing water at elevated temperatures for domestic use.
8. This unit must have an adequate supply of fresh air during
operation for proper gas combustion and venting.
9. Make sure all exhaust venting is properly installed and
maintained. Improper venting of this unit could lead to
increased levels of carbon monoxide.
10. Do not use this hot water supply boiler if any part has been
under water. Immediately call a qualified service technician
to replace the appliance. The possible damage to a flooded
hot water supply boiler can be extensive and present
numerous safety hazards. Any appliance that has been
under water must be replaced.
11. Do not alter this unit in any way. Any change to this unit or
its controls can be dangerous.
Installation & Service Manual
The Genesis - How it works...
1.
Heat exchanger
The heat exchanger allows system water to flow through
specially designed tubes for maximum heat transfer. The
glass lined headers and copper fined tubing are encased in a
jacket that contains the combustion process.
2.
Heat exchanger access cover
The heat exchanger access cover is a galvanized steel door which
allows access for service, maintenance, and removal of the
heat exchanger from inside the combustion chamber.
3.
Blower
The blower pulls in and injects air into the individual burners
along with gas from the gas manifold where the mix is burned
inside the combustion chamber.
4.
Gas valve
The gas valves (reference) have a dual purpose; changing the
gas supply pressure to manifold pressure, and the reference
side of the gas valve is designed to allow chamber pressure
to change the volume of gas through the valve and measured
as net manifold pressure. This is not a design to compensate
for gas supply pressure issues.
5.
Tank temperature sensor (not shown)
When connected, this sensor monitors tank temperature.
6.
Outlet sensor
This sensor monitors the outlet water temperature.
7.
Inlet temperature sensor
This sensor monitors inlet water temperature. If selected as
the controlling sensor and a tank sensor is not connected, the
appliance will maintain setpoint by adjusting the firing rate
of the unit according to this sensor.
8.
2-Stage electronic temperature control
The 2-stage electronic temperature control consists of a Liquid
Crystal Display (LCD) for interactive prompting during
programming and display of both sensed and assigned values.
Programming is accomplished through the use of the three (3)
programming buttons -- select, (+), and (-). This 2-stage
electronic temperature control also controls the pump.
9.
LED display board
The LED display board displays the status of the unit. LED’s
are provided for prepurge, trial for ignition, Stage 1, Stage 2,
ignition module status and alarm along with a RESET button
for resetting the ignition module.
10. Burner
The burner is a ported stainless steel construction which uses
a gas air mix to operate at a fixed input. Banks of burners
turn on or off to vary the firing rate.
11. Water outlet (system supply)
The water outlet is a 2 or 2 1/2" (depending on model) pipe
connection that supplies water to the tank with connections
for a flow switch (see #25), a relief valve (see #22).
12. Water inlet (system return)
The water inlet is a 2 or 2 1/2" (depending on model) pipe
connection that receives water from the tank and delivers it to
the heat exchanger.
13. Gas supply pipe
15. Air intake
Fresh air for combustion is drawn through a filter provided at the
air intake, located at either the rear or right side of the appliance.
16. Line voltage terminal strip
The line voltage terminal strip provides a location to connect
all of the line voltage (120 VAC) contact points to the unit.
17. Low voltage connection board(s)
The low voltage connection board provides a location to connect
all of the low voltage devices to the appliance. This is where most
of the external safety controls are connected.
18. Front doors - upper and lower
The front doors provide access to the gas train as well as the
blower, burners and other key components for service and
maintenance.
19. Hot surface igniter (HSI)
The hot surface igniter is a device that is used to ignite the
air/gas mixture as well as monitor the performance of the flame
during operation. This device acts as a flame sense electrode.
20. Flame inspection window (sight glass)
The flame inspection windows, located on either side of the
appliance, allow for visual inspection of the burners and flame
during operation.
21. Manual reset high limit sensor
This device monitors the outlet water temperature to ensure
safe operation. If the temperature exceeds its setting (field
adjustable), it will break the control circuit, shutting the
appliance down.
22. Relief valve
The relief valve is a safety device that ensures the maximum
pressure of the appliance is not exceeded. Hot water supply boilers
operate on temperature and pressure and are shipped standard as
125 PSI and 210°F (98.9°C).
23. Power switch
The power switch is used to engage and disengage power to the
appliance on the 120 VAC circuit.
24. Air pressure switch
The air pressure switch is a safety device which ensures proper
blower operation. The air pressure switch is wired in series with
the low voltage control circuit in such a way that if the fan does not
engage or shuts down prematurely the device will break the
control circuit and the unit will shut down.
25. Flow switch
The flow switch is a safety device that ensures flow through the
heat exchanger during operation. This appliance is low mass and
should never be operated without flow. The flow switch makes
contact when flow is detected and allows the unit to operate. If
flow is discontinued during operation for any reason the flow
switch will break the control circuit and the unit will shut down.
26. Drain port(s)
The drain port(s) are located underneath the front header.
27. Manual shutoff valve (not shown)
Manual valve used to isolate the unit from the gas supply.
The gas supply pipe on this appliance is 1 1/4 or 2" (depending
on model) diameter NPT. Please reference the National Fuel
Gas Code charts for connection details.
14. Hot surface ignition module
The hot surface ignition module controls the blower(s), hot
surface igniter and gas valves. A status LED is also provided for
flash codes used for the purpose of troubleshooting the unit.
5
Installation & Service Manual
The Genesis - How it works...
13
15
18
IMG00570
IMG00571
26
18
Models 400 - 750 Rear View
Models 400 - 750 Front View
14
17
9
3
8
7
4
22
6
24
25
11
IMG00573
16
23
12
21
IMG00572
10
19
20
Models 400 - 750 Right Side (inside unit)
6
2
1
Models 400 - 750 Left Side (inside unit)
Installation & Service Manual
The Genesis - How it works...
(continued)
18
13
15
25
IMG00575
IMG00574
26
18
Models 1000 - 2100 Rear View
Models 1000 - 2100 Front View
24
14
3
9
17
7
4
8
6
22
11
16
IMG00577
23
IMG00576
21
19
Models 1000 - 2100 Right Side (inside unit)
12
1
20
10
2
Models 1000 - 2100 Left Side (inside unit)
7
Installation & Service Manual
Ratings
LOW LEAD CONTENT
Genesis
Hot Water Supply Boiler Ratings
Input
MBH
Model Number
Other Specifications
GPH at 100°F Rise
(Note 3)
Note: N = Natural, P =
Propane
Appliance
Water
Water
Gas
Content Connections Connections
Gallons
Air / Vent
Sizes
(Note 2)
Min
Max
GWH0400(N,P)
250
399
412
1.6
2"
1-1/4"
6"
GWH0500(N,P)
250
500
515
1.7
2"
1-1/4"
6"
GWH0650(N,P)
350
650
670
2.0
2"
1-1/4"
8"
GWH0750(N,P)
400
750
773
2.1
2"
1-1/4"
8"
GWH1000(N,P)
360
990
1020
2.2
2-1/2"
2"
10"
GWH1250(N,P)
720
1260
1298
2.6
2-1/2"
2"
12"
GWH1450(N,P)
720
1440
1484
2.9
2-1/2"
2"
12"
GWH1800(N,P)
720
1800
1855
3.3
2-1/2"
2"
12"/14"
GWH2100(N,P)
990
2070
2133
3.6
2-1/2"
2"
12"/14"
NOTICE
Maximum allowed working pressure is located on the rating plate.
Notes:
1. The ratings are based on standard test procedures
prescribed by the United States Department of Energy.
2. Genesis models require special gas venting. Use only
the vent materials and methods specified in the Genesis
Installation and Operation Manual.
8
3. The Genesis hot water supply boiler is orificed for operation
up to 2000 feet altitude, and including up to 4,500 feet, with
no field adjustments. The appliance will de-rate by 4% for
each 1000 feet above sea level up to 4,500 feet. Consult the
factory for installations above 4,500 feet elevation.
Installation & Service Manual
1
Determine unit location
Location of unit
This unit meets the safe lighting performance criteria with
the gas manifold and control assembly provided, as specified
in the ANSI standards for gas-fired units and ANSI Z21.13 latest edition.
1. Maintain all clearances from combustible construction
when locating appliance. See Clearances from Combustible
Construction, this page.
2. Locate the appliance so that if water connections should
leak, water damage will not occur. When such locations
cannot be avoided, it is recommended that a suitable
drain pan, adequately drained, be installed under the unit.
The pan must not restrict combustion airflow. Under no
circumstances is the manufacturer to be held responsible
for water damage in connection with this unit, or any of its
components.
3. The appliance must be installed so that the ignition
system components are protected from water (dripping,
spraying, rain, etc.,) during appliance operation and service
(circulator replacement, control replacement, etc.,).
4. Appliances located in a residential garage and in adjacent
spaces that open to the garage and are not part of the living
space of a dwelling unit must be installed so that all burners
and burner ignition devices have a minimum clearance of
not less than 18" (46 cm) above the floor. The appliance
must be located or protected so that it is not subject to
physical damage by a moving vehicle.
5. DO NOT install this appliance in any location where
gasoline or flammable vapors are likely to be present.
6. The appliance must be installed on a level floor.
7. Combustible floor installation:
a. Models 400 - 750 require an approved floor kit for
installation on combustible flooring (reference Table
1A).
b. Models 1000 - 2100 are approved for installation
on combustible flooring without a floor kit. Note:
Concrete block over wood flooring is not considered
non-combustible.
8. DO NOT install this appliance directly on carpeting or
other combustible material.
9. Maintain required clearances from combustible surfaces,
reference the Indoor Clearances from Combustible
Construction Section, this page.
10. For outdoor models, you must install an optional vent
cap. Instructions for mounting the vent cap are included
in the venting section of this manual. Do not install
outdoor models directly on the ground. You must install
the outdoor unit on a concrete, brick, block, or other
non-combustible pad. Outdoor models have additional
special location and clearance requirements. See Outdoor
Installation Venting, page 31. A wind proof cabinet
protects the unit from weather.
Indoor clearances
construction
from
combustible
Maintain minimum specified clearances for adequate
operation. Allow sufficient space for servicing pipe
connections, pump and other auxiliary equipment, as well
as the unit. See rating plate for specific service clearance
requirements.
Right Side
3" (7.5 cm)
Rear
3" (7.5 cm) (3" min. from any surface)*
Left Side 6"
(15
cm) (24"
service)
(0.61
m)
suggested
for
Front
Alcove* (30" (0.76m) suggested for service)
Top
3" (7.5 cm)
Flue
1" (25.4 mm)
Vent Damper
(if equipped)
6" (24" suggested for service)
Hot Water Pipes 1" (25.4 mm)
*An Alcove is a closet without a door. Thirty-six inches (36")
to rear required for outdoor installation.
Note: No additional clearance is needed on the right side of the
unit for the observation port. An observation port is located on
both the right and left side of the unit.
Figure 1-1_Indoor clearances from combustible construction
3"
MIN
REAR
3"
MIN
TOP
3"
MIN
RIGHT
SIDE
6"
MIN
LEFT
SIDE
30"
MIN
FRONT
NOTICE
IMG00578
Clearances from combustible construction
are noted on the appliance rating plate.
TABLE - 1A
COMBUSTIBLE FLOOR KITS
Model
Kit Number
400
100131378
500
100131379
650
100131380
750
100131381
Freeze protection
Although these units are CSA International design-certified for
outdoor installations, such installations are not recommended
in areas where the danger of freezing exists. You must provide
proper freeze protection for outdoor installations, units installed
in unheated mechanical rooms or where temperatures may
drop to the freezing point or lower. If freeze protection is not
provided for the system, a low ambient temperature alarm is
recommended for the mechanical room. Damage to the unit by
freezing is non-warrantable.
9
Installation & Service Manual
1
Determine unit location
Anytime the temperature of any sensor drops below 34°F, the
control turns on the pump contact.
Figure 1-2B_Drain the unit_Models 1000 - 2100
Location
Locate indoor hot water supply boilers in a room having a temperature safely above freezing [32°F (0°C)].
 CAUTION
A mechanical room operating under a negative
draft pressure may experience a down draft in
the flue of a hot water supply boiler when
it is not firing. The cold outside air pulled
down the flue may freeze a heat exchanger.
This condition must be corrected to provide
adequate freeze protection.
Outdoor installation
A snow screen should be installed to prevent snow and ice accumulation around the unit or its venting system.
Shut-down and draining
If for any reason, the unit is to be shut off, the following
precautionary measures must be taken:
1.
Shut off gas supply.
2.
Shut off water supply.
3.
Shut off electrical supply
4.
Drain the unit completely. Remove one threaded plug
or bulbwell from the inlet side of the front header and
one from the outlet side of the front header on the heat
exchanger. Blow all water out of the heat exchanger
(see FIG.'s 1-2A and 1-2B).
5.
Drain pump and piping.
DRAIN PLUG
DR
G (2X)
Combustion and ventilation air
Provisions for combustion and ventilation air must be in
accordance with Air for Combustion and Ventilation, of the
latest edition of the National Fuel Gas Code, ANSI Z223.1/
NFPA 54, or Clause 8.2, 8.3, or 8.4 of Natural Gas and Propane
Installation Code, CAN/CSA B149.1, or applicable provisions of
the local building codes.
Provide properly-sized openings to the equipment room to
assure adequate combustion air and proper ventilation when
the unit is installed with conventional venting or sidewall
venting.
Combustion air options
Figure 1-2A_Drain the unit_Models 400 -750
 CAUTION
Under no circumstances should
the equipment room ever be under
a negative pressure. Particular care
should be taken where exhaust fans, attic
fans, clothes dryers, compressors, air
handling units, etc., may take away air
from the unit.
This unit has four combustion air options.
1. Outside Combustion Air, No Ducts
You can direct outside combustion air to this unit using either
one or two permanent openings (see FIG. 1-3).
One Opening
DRAIN PLUG
10
The opening must have a minimum free area of one square
inch per 3000 Btu input (7 cm2 per kW). You must locate this
opening within 12" (30 cm) of the top of the enclosure.
Installation & Service Manual
1
Determine unit location
2. Outside Combustion Air, Using Ducts
You can direct outside combustion air to this unit using two air
ducts to deliver the air to the equipment room (see FIG. 1-4).
Each of the two openings must have a minimum free area of one
square inch per 2000 Btu input (11cm2 per kW).
3. Combustion Air from Interior Space
You can direct combustion air to this unit using air from an
adjoining interior space. You must provide two openings from
the equipment room to the adjoining room (see FIG. 1-5).
Each of the two openings must have a net free area of one square
inch per 1000 Btu input (22cm2 per kW), but not less than 100
square inches (645cm2).
IMG00579
Figure 1-3_Outside Combustion Air - Single Opening
Two Openings
The combustion air opening must have a minimum free area of
one square inch per 4000 Btu/hr input (5.5 cm2 per kW). You
must locate this opening within 12" (30 cm) of the bottom of the
enclosure (see FIG. 1-4).
The ventilation air opening must have a minimum free area of
one square inch per 4000 Btu/hr input (5.5 cm2 per kW). You
must locate this opening within 12" (30 cm) of the top of the
enclosure.
IMG00581
Figure 1-5_Combustion Air from Interior Space
IMG00580
Figure 1-4_Outside Combustion Air - Two Openings
11
Installation & Service Manual
1
Determine unit location
All dimensions are based on net free area in square inches.
Metal louvers or screens reduce the free area of a combustion
air opening a minimum of approximately 25%. Check with
louver manufacturers for exact net free area of louvers. Where
two openings are provided, one must be within 12" (30 cm) of
the ceiling and one must be within 12" (30 cm) of the floor of
the equipment room. Each opening must have a minimum net
free area as specified in TABLE 1B. Single openings shall be
installed within 12" (30 cm) of the ceiling.
 CAUTION
IMG00582
Figure 1-6_Outside Combustion Air Through Ducts
4. Outside Combustion Air - Using Direct Venting
With this option, you can connect combustion air vent piping
directly to the unit. See the information under Direct Venting
starting on page 27 for specific information regarding this
option.
The combustion air supply must be
completely free of any flammable vapors
that may ignite or chemical fumes which
may be corrosive to the appliance. Common
corrosive chemical fumes which must be
avoided are fluorocarbons and other
halogenated compounds, most commonly
present as refrigerants or solvents, such as
Freon, trichlorethylene, perchlorethylene,
chlorine, etc.
These chemicals, when
burned, form acids which quickly attack
the heat exchanger finned tubes, headers,
flue collectors, and the vent system. The
result is improper combustion and a nonwarrantable, premature unit failure.
TABLE - 1B
MINIMUM RECOMMENDED COMBUSTION
AIR SUPPLY TO EQUIPMENT ROOM
*Outside Air from
Inside Air from
2 Openings Directly from *Outside Air from
2 Ducts Delivered from
Model
1 Opening Directly
Outdoors
Outdoors
Number
Top
Bottom
Top
Bottom
from Outdoors, in2
Opening, in2 Opening, in2
Opening, in2 Opening, in2
100
133
200
200
100
400
(645 cm2)
(858 cm2)
(1291 cm2)
(1291 cm2)
(645 cm2)
125
167
250
250
125
500
(806 cm2)
(1077 cm2)
(1613 cm2)
(1613 cm2)
(806 cm2)
163
163
217
325
325
650
(1052 cm2)
(1052 cm2)
(1400 cm2)
(2097 cm2)
(2097 cm2)
188
188
250
375
375
750
(1213 cm2)
(1213 cm2)
(1613 cm2)
(2420 cm2)
(2420 cm2)
Inside Air from
2 Ducts Delivered from
Interior Space
Top
Bottom
Opening, in2 Opening, in2
400
400
(2581 cm2)
(2581 cm2)
500
500
(3226 cm2)
(3226 cm2)
650
650
(4194 cm2)
(4194 cm2)
750
750
(4839 cm2)
(4839 cm2)
1000
248
(1600 cm2)
248
(1600 cm2)
330
(2129 cm2)
495
(3194 cm2)
495
(3194 cm2)
990
(6388 cm2)
990
(6388 cm2)
1250
315
(2032cm2)
360
(2323cm2)
450
(2903cm2)
518
(3342cm2)
315
(2032cm2)
360
(2323cm2)
450
(2903cm2)
518
(3342cm2)
420
(2710 cm2)
480
(3097 cm2)
600
(3871 cm2)
690
(4452 cm2)
630
(4065 cm2)
720
(4646 cm2)
900
(5807 cm2)
1035
(6678 cm2)
630
(4065 cm2)
720
(4646 cm2)
900
(5807 cm2)
1035
(6678 cm2)
1260
(8130 cm2)
1440
(9291 cm2)
1800
(11614 cm2)
2070
(13356 cm2)
1260
(8130 cm2)
1440
(9291 cm2)
1800
(11614 cm2)
2070
(13356 cm2)
1450
1800
2100
*Outside air openings shall directly communicate with the outdoors. When combustion air is drawn from the outside through a
duct, the net free area of each of the two openings must have twice (2 times) the free area required for Outside Air/2 Openings. The
above requirements are for the hot water supply boiler only; additional gas fired appliances in the equipment room will require an
increase in the net free area to supply adequate combustion air for all appliances.
12
Installation & Service Manual
1
Determine unit location
(continued)
Exhaust fans
Combustion air filter
Any fan or equipment which exhausts air from the equipment
room may deplete the combustion air supply and/or cause a
down draft in the venting system. Spillage of flue products from
the venting system into an occupied living space can cause a
very hazardous condition that must be immediately corrected.
If a fan is used to supply combustion air to the equipment
room, the installer must make sure that it does not cause drafts
which could lead to nuisance operational problems with the
unit.
This unit has a standard air filter located at the combustion
air inlet. This filter helps ensure clean air is used for the
combustion process. Check this filter every month and replace
when it becomes dirty. The filter size on Models 400 - 750 is
12" x 12"
x 1" (30.5cm x 30.5cm x 2.5cm) and 16" x 16" x 1"
(40.6cm x 40.6cm x 2.5 cm) on Models 1000 - 2100. You can
find these commercially available filters at any home center or
HVAC supply store.
Vertical Vent/Air, Horizontal Vent/Air, and Direct Vent
venting systems have specific requirements for combustion air
ducts from the outside which are directly connected to the unit.
See the requirements for combustion air duct in the venting
section.
Use of filters having MERV (Minimum
NOTICE
Efficiency Reporting Value) ratings higher
than 4 is not recommended. Higher efficiency
low-micron filters can limit combustion
air leading to either nuisance problems or
potential component damage if used over
prolonged periods of time. Filters having
a MERV rating of 5 to 6 may be used
on a limited basis during the construction
phase of a project provided they are replaced
once filter loading becomes apparent. After
the construction phase is completed, it is
recommended that the filter be changed to a
4 or lower MERV disposable type filter.
Figure 1-7_Metal Panel Covering Side Combustion
Air Inlet
For convenience and flexibility, you can direct the combustion
air inlet from either the back or right side of the unit. To arrange
the combustion air inlet for side entry, follow the steps below:
1. Remove the metal panel from the unit’s side wall (see
FIG. 1-7).
2. Remove screws from the air filter/bracket assembly.
3. Move the filter/bracket assembly from the rear of unit to the
side opening (see FIG. 1-8).
4. Attach filter/bracket assembly to the unit’s side using the
pre-drilled screw holes.
5. Attach the metal panel to the rear combustion air opening
to seal it off.
Figure 1-8_Moving Air Filter / Bracket Assembly from
Rear of Unit to Side
NOTICE
During construction the air filter should be checked more frequently to ensure it does not become clogged with
combustion dirt and debris.
CAUTION
Sustained operation of an appliance with a clogged filter may result in nuisance operational problems, bad
combustion, and non-warrantable component failures.
13
Installation & Service Manual
2
Venting
BEFORE YOU BEGIN
Identify your appliance’s vent system:
This manual covers venting requirements for CAT I models and CAT IV vent materials. Be sure to correctly identify the type of
vent system your appliance requires before proceeding.
GWH0400(N,P)
GWH0500(N,P)
GWH0650(N,P)
GWH0750(N,P)
GWH1000(N,P)
GWH1250(N,P)
GWH1450(N,P)
GWH1800(N,P)
GWH2100(N,P)
 DANGER
Venting options:
A B C D
E
F
= B-Vent Material
CAT I
= Direct Vent Options
CAT IV
= Outdoor Vent Option
Failure to use correct venting materials can result in loss of life from flue gas spillage into working or living
space.
Venting Category Definitions: (Reference National Fuel Gas Code ANSI Z223.1)
CAT I: Negative pressure non-condensing
An appliance that operates with a non-positive vent static pressure with a vent gas temperature that avoids excessive condensate
production in the vent.
CAT IV: Positive pressure condensing
An appliance that operates with a positive vent static pressure with a vent gas temperature that may cause excessive condensate
production in the vent.
CAT IV Flue pipe materials
The following manufacturers supply flue materials suitable for these models when installed as CAT IV. All materials are made
with AL29-4C stainless steel.
Heat-Fab Inc., Saf-T CI Vent with AL29-4C stainless steel
Protech Systems Inc., Fas N Seal Vent with AL29-4C stainless steel
Metal-Fab Inc., Corr/Guard Vent with AL29-4C stainless steel
Or other listed Category IV vent systems suitable for a condensing, positive pressure, gas fired appliance.
A Category IV flue MUST have all vent joints and seams sealed gastight and have provisions for a drain to properly collect and
dispose of condensate that may occur in the venting system.
14
Installation & Service Manual
2
Venting
(continued)
Vent system options:
A
(Note: Installations shown below are representative, actual installations may vary from those shown.)
This option uses a vertical rooftop flue termination
with air supplied from the equipment room - see
page 17.
D
This option uses a powered vent assembly to
exhaust the flue products out a sidewall with air
supplied by a pipe from the sidewall - see page 26.
SIDEWALL/POWER VENTING/
DUCTED AIR
CONVENTIONAL NEGATIVE
DRAFT VENTING
NOTE: CAT I B-VENT MATERIALS MAY BE USED WHEN THE
POWERED VENT IS CONNECTED DIRECTLY TO THE OUTSIDE
VENT CAP. IF THE POWERED VENT IS NOT CONNECTED
DIRECTLY TO THE OUTSIDE VENT CAP, THEN CAT IV - AL29-4C
VENT MATERIALS MUST BE USED FROM THE POWERED VENT
TO THE OUTSIDE VENT CAP.
3'
MIN
12"
MIN
IMG00580
B
This option uses a vertical conventional vent for
flue products with air supplied by a pipe from the
sidewall or rooftop - see page 20.
IMG00584
E
VERTICAL VENT/DUCTED AIR
This option uses a sealed AL29-4C flue and a
separate combustion air pipe to the outdoors.
This system terminates both the flue and
combustion air inlet in the same pressure zone
- see page 27.
DIRECT VENT/SEALED
COMBUSTION
3'
MIN
12"
MIN
IMG00583
C
This option uses a powered vent assembly to
exhaust the flue products out a sidewall vent
termination with air supplied from the equipment
room - see page 23.
SIDEWALL/POWER VENTING
IMG00585
F
This option uses the installation of a special air
inlet / vent cap on top of the unit - see page 31.
OUTDOOR VENTING
NOTE: CAT I B-VENT MATERIALS MAY BE USED WHEN THE
POWERED VENT IS CONNECTED DIRECTLY TO THE OUTSIDE
VENT CAP. IF THE POWERED VENT IS NOT CONNECTED
DIRECTLY TO THE OUTSIDE VENT CAP, THEN CAT IV - AL29-4C
VENT MATERIALS MUST BE USED FROM THE POWERED VENT
TO THE OUTSIDE VENT CAP.
15
Installation & Service Manual
2
Venting
General information
You must supply adequate combustion and ventilation air to this unit. You must provide minimum clearances for the vent
terminal from adjacent buildings, windows that open, and building openings. Follow all requirements set forth in the latest edition
of the National Fuel Gas Code, ANSI Z223.1, in Canada, the latest edition of CAN/CGA Standard B149 Installation Code for Gas
Burning Appliances and Equipment or applicable local building codes. Vent installations for connection to gas vents or chimneys
must be in accordance with “Venting of Equipment” of the above-mentioned standards.
NOTICE
Examine the venting system at least once each year. Check all joints and vent pipe connections for tightness.
Also check for corrosion or deterioration. If you find any problems, correct them at once.
Venting support
Support horizontal portions of the venting system to prevent sagging. Provide an upward slope of at least 1/4 inch per foot
(21mm/m) on all horizontal runs from the unit to the vertical flue run or to the vent terminal on sidewall venting installations.
Do not use an existing chimney as a raceway if another appliance or fireplace is vented through the chimney. The weight of the
venting system must not rest on the unit. Provide adequate support of the venting system. Follow all local and applicable codes.
Secure and seal all vent connections. Follow the installation instructions from the vent material manufacturer.
Barometric damper location
Any venting system option that requires a barometric damper must adhere to the following directions for optimum performance.
The preferred location for the barometric damper is in a tee or collar installed in the vertical pipe rising from the unit’s flue outlet.
The barometric damper MUST NOT be installed in a bull head tee installed on the unit’s flue outlet. The tee or collar containing
the barometric damper should be approximately three feet vertically above the connection to the unit’s flue outlet. This location
ensures that any positive velocity pressure from the unit’s internal combustion fan is dissipated and the flue products are rising
due to buoyancy generated from the temperature of the flue products. Adjust the weights on the damper to ensure that draft is
maintained within the specified range.
TABLE - 2A
FLUE AND AIR INLET PIPE SIZES
MODEL
FLUE SIZE
AIR INLET SIZE
MODEL
FLUE SIZE
AIR INLET SIZE*
400
500
650
750
--
6"
6"
8"
8"
--
6"
6"
8"
8"
--
1000
1250
1450
1800
2100
10"
12"
12"
14"
14"
10"
12"
12"
12"
12"
*Minimum diameter for air inlet pipe. Installer may increase diameter one pipe size for ease of installation, if needed.
16
Installation & Service Manual
2
Venting
(continued)
Conventional negative draft venting - see page 15.
A
NOTICE
Before installing a venting system, follow requirements found in the General Venting section.
This option uses Type-B double-wall flue outlet piping. The blower brings in combustion air. The buoyancy of the
heated flue products cause them to rise up through the flue pipe. The flue outlet terminates at the rooftop.
Negative draft
IMG00580
The negative draft in a conventional vent installation must be within the range of 0.02 to 0.08 inches w.c. to ensure
proper operation. Make all draft readings while the unit is in stable operation (approximately 2 to 5 minutes).
Connect the flue vent directly to the flue outlet opening on the top of the unit. No additional draft diverter or
barometric damper is needed on single unit installations with a dedicated stack and a negative draft within the
specified range of 0.02 to 0.08 inches w.c. If the draft in a dedicated stack for a single unit installation exceeds the
maximum specified draft, you must install a barometric damper to control draft. Multiple unit installations with
combined venting or common venting with other Category I negative draft appliances require each hot water supply
boiler to have a barometric damper installed to regulate draft within the proper range.
Do not connect vent connectors serving appliances vented by natural draft (negative draft) to any portion of a
mechanical draft system operating under positive pressure. Connecting to a positive pressure stack may cause flue
products to be discharged into the living space causing serious health injury.
Flue outlet piping
With this venting option, you must use Type-B double-wall vent materials. Vent materials must be listed by a
nationally-recognized test agency for use as vent materials. Make the connections from the unit vent to the outside
stack as direct as possible with no reduction in diameter. Use the National Fuel Gas Code venting tables for
double-wall vent to properly size all vent connectors and stacks. Follow the vent manufacturer’s instructions when
installing Type-B vents and accessories, such as firestop spacers, vent connectors, thimbles, caps, etc.
Provide adequate clearance to combustibles for the vent connector and firestop.
When planning the venting system, avoid possible contact with plumbing or electrical wiring inside walls, ceilings,
and floors. Locate the unit as close as possible to a chimney or gas vent.
Avoid long horizontal runs of the vent pipe, 90° elbows, reductions and restrictions.
No additional draft diverter or barometric damper is required on single unit installations with a dedicated stack and
a negative draft maintained between 0.02 to 0.08 inches w.c.
Common Venting Systems
You can combine the flue with the vent from any other negative draft, Category I appliance. Using common venting
for multiple negative draft appliances requires you to install a barometric damper with each unit. This will regulate
draft within the proper range. You must size the common vent and connectors from multiple units per the venting
tables for Type-B double-wall vents in the latest edition of the National Fuel Gas Code, ANSI Z223.1 and/or CAN/
CGA-B149 Installation Code.
Common venting systems may be too large when an existing unit is removed.
At the time of removal of an existing appliance, the following steps shall be followed with each appliance remaining
connected to the common venting system placed in operation, while other appliances remaining connected to the
common venting system are not in operation.
1. Seal any unused opening in the common venting system.
2. Visually inspect the venting system for proper size and horizontal pitch. Make sure there is no blockage or
restriction, leakage, corrosion and other unsafe conditions.
3. If possible, close all building doors and windows. Close all doors between the space in which the appliances
remaining connected to the common venting system are located and other building spaces.
17
Installation & Service Manual
2
Venting
4. Turn on clothes dryers and any other appliances not connected to the common venting system. Turn on any exhaust fans, such
as range hoods and bathroom exhausts, so they will operate at maximum speed. Do not operate a summer exhaust fan.
5. Close fireplace dampers.
6. Place in operation the unit being inspected. Follow the lighting instructions. Adjust thermostat so unit will operate continuously.
7. Test for spillage at the draft hood/relief opening after 5 minutes of main burner operation. Use the flame of a match or candle,
or smoke from a cigarette, cigar or pipe.
8. After making sure that each appliance remaining connected to the common venting system properly vents when tested as
above, return doors, windows, exhaust fans, fireplace dampers and other gas burning appliances to their previous conditions
of use.
9. Correct any improper operation of the common venting system so that the installation conforms to the latest edition of the
National Fuel Gas Code, ANSI Z223.1/NFPA 54, and/or the Natural Gas and Propane Installation Code, CAN/CSA B149.1
Installation Code for Gas Burning Appliances and Equipment. When resizing any portion of the common venting system,
resize to approach the minimum size as determined using the appropriate tables of the latest edition of the National Fuel Gas
Code, ANSI Z223.1/NFPA 54, and/or the Natural Gas and Propane Installation Code, CAN/CSA B149.1 Installation Code for
Gas Burning Appliances and Equipment.
Masonry chimney installations
A masonry chimney must be properly sized for the installation of a high efficiency gas-fired appliance. Venting of a high efficiency
appliance into a cold or oversized masonry chimney can result in operational and safety problems. Exterior masonry chimneys,
with one or more sides exposed to cold outdoor temperatures, are more likely to have venting problems. The temperature of the
flue products from a high efficiency appliance may not be able to sufficiently heat the masonry structure of the chimney to generate
proper draft. This will result in condensing of flue products, damage to the masonry flue/tile, insufficient draft and possible spillage
of flue products into an occupied living space. Carefully inspect all chimney systems before installation.
 WARNING
NOTICE
Do not vent this unit into a masonry chimney without a sealed stainless steel liner system. Any breaks, leaks,
or damage to the masonry flue/tile will allow the flue products to leak from the chimney and into occupied
living spaces. This could cause serious injury or death due to carbon monoxide poisoning and other harmful
flue products.
Check with local code officials to determine code requirements or the advisability of using a masonry chimney
with a sealed corrosion-resistant liner system.
Inspection of a masonry chimney
A masonry chimney must be carefully inspected to determine its suitability for the venting of flue products. A clay-tile-lined
chimney must be structurally sound, straight and free of misaligned tile, gaps between liner sections, missing sections of liner or any
signs of condensate drainage at the breaching or clean out. If there is any doubt about the condition of a masonry chimney, it must
be relined with a properly-sized and approved chimney liner system. An unlined masonry chimney must not be used to vent flue
products from this high-efficiency unit. An unlined chimney must be relined with an approved chimney liner system when a new
appliance is being attached to it. Metallic liner systems (Type-B double-wall or flexible or rigid metallic liners) are recommended.
Consult with local code officials to determine code requirements or the advisability of using or relining a masonry chimney.
Vertical vent termination clearances and location
The vent terminal should be vertical and exhaust outside the building at least 2 feet (0.61m) above the highest point of the roof
within a 10 foot (3.05m) radius of the termination.
The vertical termination must be a minimum of 3 feet (0.91m) above the point of exit.
A vertical termination less than 10 feet (3.05m) from a parapet wall must be a minimum of 2 feet (0.61m) higher than the parapet
wall.
Keep the vent cap clear of snow, ice, leaves, and debris to avoid blocking the flue.
18
Installation & Service Manual
2
Venting
(continued)
Figure 2-1_Vent Termination from Peaked Roof - 10 ft.
or Less From Ridge
NOTICE
Figure 2-2_Vent Termination from Peaked Roof - 10 ft.
or More From Ridge
Vent terminations are not shown in FIG.’s 2-1 thru 2-4. Make sure all vertical vents are installed with vent
terminations recommended by the vent manufacturer.
Figure 2-3_Vent Termination from Flat Roof - 10 ft.
or Less From Parapet Wall
Figure 2-4_Vent Termination from Flat Roof - 10 ft. or
More From Parapet Wall
19
Installation & Service Manual
2
Venting
Vertical Vent/Ducted Air - see page 15.
B
NOTICE
Before installing a venting system, follow requirements found in the General Venting section.
The Vertical Vent/Ducted Air vent system is the same as the Conventional Negative Draft vent system, except it pulls
combustion air from the outdoors through a separate air inlet pipe. Follow all requirements in the Conventional
Negative Draft Venting section on page 17.
IMG00583
The Vertical Vent/Ducted Air vent system requires you to install two pipes directly to the unit; one vertical pipe
with a rooftop termination for the flue products and one pipe for combustion air. For this venting option, you must
purchase the DV box adapter from the appliance manufacturer. The DV box attaches to the air inlet of the unit. The
pipe for combustion air attaches to the DV box (see FIG. 2-10 on page 29). Reference page 29 for a list of approved
air intake materials.
Combustion air inlet piping
 WARNING
Locate and install the combustion air inlet cap correctly. Failure to do so can allow the discharge of flue products
to be drawn into the combustion process. This can result in incomplete combustion and potentially hazardous
levels of carbon monoxide in the flue products. This will cause operational problems and the spillage of flue
products. Spillage of flue products can cause personal injury or death due to carbon monoxide poisoning.
The sidewall or vertical rooftop Vent/Ducted Air combustion air supply system has specific material and installation requirements.
The air inlet pipe connects directly to the unit to supply combustion air. In most installations, the combustion air inlet pipe will
be a dedicated system with one air inlet pipe per unit. You can combine multiple air inlets if the guidelines in Combined Air Inlet
Points, page 21 are followed. The air inlet pipe will be connected to a combustion air inlet cap as specified in this section.
For normal installations, this system uses a single-wall pipe to supply combustion air from outdoors directly to the unit.
In cold climates, use a Type-B double-wall vent pipe or an insulated single-wall pipe for combustion air. This will help prevent
moisture in the cool incoming air from condensing and leaking from the inlet pipe.
Length of air inlet pipe
The installed length of air inlet pipe from the unit to the outside air inlet cap must not exceed 50 equivalent feet (15.2m). Subtract
5 feet (1.5m) of equivalent length for each 90° elbow. Subtract 2.5 feet (0.7m) of equivalent length for each 45° elbow.
Do not exceed the limits for the combustion air inlet piping lengths.
Sidewall air inlet
The sidewall air inlet cap is supplied in the Sidewall Air Inlet Kit. Order the kit from the appliance manufacturer. This sidewall
cap supplies combustion air for a single unit only. See Table 2B, page 22, for kit numbers.
Locate the unit as close as possible to the sidewall where you will install the combustion air supply system.
IMG00583
Figure 2-5_Sidewall Combustion Air Inlet
20
Figure 2-6_Air Inlet Cap for Sidewall Termination
Installation & Service Manual
2
Venting
(continued)
To prevent recirculation of flue products from an adjacent vent cap into the combustion air inlet, follow all applicable clearance
requirements in the latest edition of the National Fuel Gas Code and/or CAN/CGA-B149 Installation Code and instructions in the
Installation and Operation Manual.
Clearances
You must install the combustion air inlet cap at least one foot (0.30m) above ground level and above normal snow levels.
The point of termination for the combustion air inlet cap must be at least 3 feet (0.91m) below the point of flue gas termination if
it is located within 10 feet (3.05m) of the flue outlet. Make sure to properly install the air inlet cap assembly on the air inlet pipe.
Do not install the combustion air inlet cap closer than 10 feet (3.05m) from an inside corner of an L-shaped structure.
Vertical Rooftop Air Inlet
Use the vertical air inlet terminations available from the appliance manufacturer, recommended and/or supplied by the vent
manufacturer, or use two 90° elbows as described on page 30.
3'
MIN
You must locate the air inlet termination elbow at least 12"
(30cm) above the roof or above normal snow levels.
If the air inlet cap is within a 10-foot (3.05m) radius of the flue
outlet, the point of termination for the combustion air inlet
cap must be at least 3 feet (0.91m) below the point of flue gas
termination (vent cap).
12"
MIN
Do not install the combustion air inlet cap closer than 10 feet
(3.05m) from an inside corner of an L-shaped structure.
Combined air inlet points
The air inlet pipes from multiple units can be combined to a
single common connection if the common air inlet pipe has a
cross sectional area equal to or larger than the total area of all air
inlet pipes connected to the common air inlet pipe.
IMG00586
Figure 2-7_Rooftop Combustion Air Inlet
Example: Two 10" air inlet pipes (78.5 in2 area each) have a total
area of 157 in2 and will require a 15" (176.7 in2 area) common
air inlet pipe.
The air inlet point for multiple unit air inlets must be provided with an exterior opening which has a free area equal to or greater
than the total area of all air inlet pipes connected to the common air inlet. This exterior opening for combustion air must connect
directly to the outdoors. The total length of the combined air inlet pipe must not exceed a maximum of 50 (15.2m) equivalent feet.
Subtract 5 feet (1.5m) for each 90° elbow in the air inlet pipe. You must deduct the restriction in area provided by any screens, grills
or louvers installed in the common air inlet point. These are common on the sidewall air inlet openings. Screens, grills or louvers
installed in the common air inlet can reduce the free area of the opening from 25% to 75% based on the materials used.
You can terminate the combustion air pipe either horizontally with a sidewall air inlet or vertically with a rooftop air inlet. The
installed length of air inlet pipe from the unit to the outside air inlet cap must not exceed 50 equivalent feet (15.2m).
21
Installation & Service Manual
2
Venting
 WARNING
3'
MIN
12"
MIN
Only use a sidewall air inlet cap supplied by the appliance
manufacturer or a rooftop air inlet cap supplied by either the vent
or appliance manufacturer. Using any other air inlet cap for single
unit installations or using a common air inlet cap for multiple
units with insufficient free area and/or protections from wind and
weather may result in operational problems and the spillage of
flue products. Spillage of flue products can cause personal injury
or death due to carbon monoxide poisoning.
For single unit installations with sidewall air inlet you must order the sidewall
air inlet kit from the appliance manufacturer. The part number for each SVK kit
is listed by unit size in Table 2B.
IMG00586
For single unit installations with rooftop air inlet (see FIG. 2-8), you must order
the rooftop air inlet kit from the appliance manufacturer. The part number for
each VDK kit is listed by unit size in Table 2B. Purchase the flue pipe, rooftop
flue termination, and air inlet pipe locally.
Figure 2-8_Vertical Vent/Ducted Air There is no vent kit for combined air supply systems for multiple units. Make
Installation w/Rooftop Combustion Air Inlet sure the air inlet cap is properly sized. You must purchase this cap locally.
Venting of flue products
For venting flue products vertically to the outdoors, follow all requirements in
the installation instructions for conventional venting in this manual.
Follow all clearance requirements in Vertical Vent Termination Clearances and
Location on page 18.
A barometric damper is not required in the flue on Vertical Vent/Air
installations if the draft is within the negative 0.02 to 0.08 inches w.c. required
for proper operation. If the draft exceeds this range, install a barometric damper.
TABLE - 2B
MODEL
400
500
650
750
1000
1250
1450
1800
2100
VERTICAL VENT/AIR KITS
HORIZONTAL KIT*
100131407
100131407
100131408
100131408
100131409
100131410
100131410
100131410
100131410
VERTICAL KIT*
100131398
100131398
100131399
100131399
100131400
100131401
100131401
100131401
100131401
*The SVK kits include a DV box adapter and sidewall air inlet cap. The VDK kits include a DV box adapter and a rooftop air inlet cap.
22
Installation & Service Manual
2
Venting
(continued)
Sidewall venting - see page 15.
C
NOTICE
Before installing a venting system, follow all requirements found in the General Venting
section.
This option uses a powered vent assembly which pulls the flue products out of the stack. This fan generates a negative
draft at the unit. Combustion air is drawn from the equipment room (see Combustion and Ventilation Air on 10).
Sidewall with fan
The sidewall fan can be mounted on the inside/outside (depending upon model) with a sidewall vent hood installed
on the exterior wall. The sidewall fan and accessories are included in a venting kit provided by the appliance
manufacturer. See Table 2C on page 25 for kit numbers.
The venting kit includes the sidewall fan, vent hood, tapered vent adapter, barometric damper (1000 - 2100 Models),
proving switch and all necessary relays to interlock with the heaters control system. The tapered vent adapter
reduces the vent size at the inlet to the fan. There should be no reduction in vent diameter from the unit’s flue outlet
to the sidewall fan. The barometric damper must be installed on the flue and adjusted to supply a negative draft
within the range of 0.04 to 0.08 inches w.c. while unit is operating.
Flue outlet piping
With this venting option, you must use Type-B double-wall (or equivalent) vent materials. Vent materials must be
listed by a nationally-recognized test agency for use as vent materials. Make the connections from the unit vent to the
sidewall fan/cap as direct as possible with no reduction in diameter. Use the National Fuel Gas Code venting tables
for double-wall vent to properly size all vent connectors and stacks. Follow the vent manufacturer’s instructions
when installing Type-B vents and accessories, such as firestop spacers, vent connectors, thimbles, caps, etc.
When planning the venting system, avoid possible contact with plumbing or electrical wiring inside walls.
The maximum installed length of sidewall vent pipe with an induced draft fan must not exceed 100 feet (30.5m).
Subtract 5 feet (1.5m) for each 90° elbow. Subtract 2.5 feet (0.7m) for each 45° elbow.
Sidewall venting termination
The sidewall vent cap must be installed on an exterior sidewall. The sidewall fan/powered sidewall vent cap and
accessories are included in a venting kit which is furnished by the appliance manufacturer in accordance with CSA
International requirements. This venting kit includes the powered sidewall fan/cap, proving switch and all necessary
relays to interlock with the heaters control system.
The sidewall fan/powered vent cap must be interlocked with the units control system to start the fan on a call for
heat and prove fan operation before the hot water supply boiler fires. Plug-in and terminal strip connections are
provided on the unit for easy connection of the factory supplied vent kit and control package for the sidewall vent
fan. See the installation instructions provided with the vent kit.
Sidewall vent termination clearances and location
Locate the bottom of the vent terminal at least 12 inches (30cm) above grade and above normal snow levels. Locate
the bottom of the vent terminal at least 7 feet (2.13m) above grade when located adjacent to public walkways. Do
not terminate directly above a public walkway.
Do not terminate the venting system in a window well, stairwell, alcove, courtyard, or other recessed area. Do not
terminate the venting system below grade.
Locate vent termination at least 3 feet (0.91m) from an inside corner of an L-shaped structure.
Provide a minimum clearance of 4 feet (1.2m) horizontally from electric meters, gas meters, regulators, and relief
equipment. Never locate vent cap above or below electric meters, gas meters, regulators, and relief equipment unless
a 4 foot (1.2m) horizontal clearance is maintained.
23
Installation & Service Manual
2
Venting
Terminate the venting system at least 3 feet (0.9m) above any forced air inlet within 10 feet (3.05m).
Terminate the venting system at least 4 feet (1.2m) below, 4 feet (1.2m) beside, or 1 foot (30cm) above any door, window, or gravity
air inlet into any building.
Locate vent termination at least 8 feet (2.4m) horizontally from any combustion air intake located above the sidewall termination
cap.
 CAUTION
Units which are shut down or will not operate may experience freezing due to convective air flow in the flue
pipe, through the air inlet, or from negative pressure in the equipment room. In cold climates, operate the
pump continuously to help prevent freezing of unit water. Provide proper freeze protection. See Freeze
Protection, page 44.
Sidewall venting without fan
For Models 400 - 750 which are approved for sidewall venting without an external power vent fan, you must install specific vent
kits and venting materials (reference Table 2C on page 25 for kit numbers).
The following is a detailed explanation of Sidewall Venting Without an External Power Vent Fan installation requirements.
Flue outlet piping
Venting Guidelines
If using this venting option, a sealed AL29-4C venting system for flue products is required on all models of this appliance. This
venting system operates with a positive pressure in the vent. The internal combustion air blower generates this positive pressure
which operates the combustion process and also exhausts the flue products from the building.
This vent system has specific vent material and installation requirements. Only use listed sealed AL29-4C vent system materials.
Follow all installation requirements. See Table 2A for proper pipe size for your unit. A list of sealed AL29-4C flue pipe
manufacturers is located on page 14.
Seal all vent joints and seams gas-tight.
Drain tee installation
A drain tee must be installed in the vent pipe to collect and dispose of any condensate that may occur in the vent system. The drain
tee must be installed as the first fitting after the horizontal ell on the top of the unit (see FIG. 2-9). Plastic drain tubing, sized per
the vent manufacturer’s instructions, shall be provided as a drain line from the tee. The drain tubing must have a trap provided by
a 3" (7.6cm) diameter circular trap loop in the drain tubing. Prime the trap loop by pouring a small quantity of water into the drain
hose before assembly to the vent. Secure the trap loop in position with nylon wire ties. Use caution not to collapse or restrict the
condensate drain line with the nylon wire ties. The condensate drain must be routed to a suitable drain for disposal of condensate
that may occur in the direct vent system. Refer to the condensate drain installation instructions as supplied by the manufacturer
of the vent material.
IMG00587
Figure 2-9_Sidewall Vent - Models 400 - 750 (Only)
24
Installation & Service Manual
2
Venting
 WARNING
(continued)
Do not combine the flue from this unit with the vent from any other appliance. Do not combine flues from
multiple appliances into a common vent. The flue from this unit must be a dedicated stack.
Connect the flue vent directly to the flue outlet opening on the top of the unit. Make the connections from the unit vent to the
outside stack as direct as possible with no reduction in diameter. Provide adequate clearance to combustibles for the vent connector
and firestop. Follow the vent manufacturer’s instructions when installing sealed AL29-4C vents and accessories, such as firestop
spacers, vent connectors, thimbles, caps, etc.
Provide adequate clearance to combustibles for the vent connector and firestop.
When planning the venting system, avoid possible contact with plumbing or electrical wiring inside walls, ceilings, and floors.
Locate the unit as close as possible to chimney or gas vent. When a vent system is disconnected for any reason, the flue must be
reassembled and resealed according to the vent manufacturer’s instructions.
The installed length of flue from the unit to the outside point of termination must not exceed 50 equivalent feet (15.2m). Subtract
5 feet (1.5m) of equivalent length for each 90° elbow. Subtract 2.5 feet (0.7m) of equivalent length for each 45° elbow.
Sidewall vent termination clearances and location
Follow all sidewall venting termination information for clearances and location under Sidewall Vent Termination Clearances and
Location on page 23.
TABLE - 2C
SIDEWALL VENT KITS
MODEL
KIT
(W/POWER FAN ASSY.)
MAX. VENT
LENGTH
VENT TERMINATION
ONLY
(MODELS 400 - 750)
MAX. VENT
LENGTH
400
100131393
100 ft.
100131416
50 ft.
500
100131393
100 ft.
100131416
50 ft.
650
100131394
100 ft.
100131417
50 ft.
750
100131394
100 ft.
100131417
50 ft.
1000
100131395*
100 ft.
N/A
N/A
1250
100131396*
100 ft.
N/A
N/A
1450
100131396*
100 ft.
N/A
N/A
1800
100131397*
100 ft.
N/A
N/A
2100
100131397*
100 ft.
N/A
N/A
*These kits include a barometric damper.
25
Installation & Service Manual
2
Venting
Horizontal Vent/Ducted Air venting (Powered Venting) - see page 15.
D
NOTICE
Before installing a venting system, follow all requirements found in the General Venting
section.
The Horizontal Vent/Ducted Air vent system is the same as the Sidewall Venting system, except it pulls combustion
air from the outdoors through a sidewall air inlet. Follow all requirements in Sidewall Venting section on page 23.
NOTE: CAT I B-VENT MATERIALS MAY BE USED WHEN THE
POWERED VENT IS CONNECTED DIRECTLY TO THE OUTSIDE
VENT CAP. IF THE POWERED VENT IS NOT CONNECTED
DIRECTLY TO THE OUTSIDE VENT CAP, THEN CAT IV - AL29-4C
VENT MATERIALS MUST BE USED FROM THE POWERED VENT
TO THE OUTSIDE VENT CAP.
3'
MIN
12"
MIN
IMG00584
The Horizontal Vent/Ducted Air vent system requires you to install two pipes directly to the unit; one pipe for flue
products and one for combustion air. Install both pipes horizontally with a sidewall termination point. For this
venting option, you must purchase the DV box accessory from the appliance manufacturer. The DV box attaches to
the air inlet of the unit. The pipe for combustion air attaches to the DV box (see FIG. 2-10 on page 29). Reference
page 29 for a list of approved air intake materials.
Make vent connection directly to the top of the unit. No additional draft diverter or barometric damper is required
on single unit installations with a dedicated stack and a negative draft maintained between 0.04 to 0.08 inches w.c.
The Horizontal Vent/Ducted Air combustion air supply system has specific vent material and installation
requirements. The air inlet pipe connects directly to the unit to supply combustion air. The combustion air inlet
pipe is a dedicated system with one air inlet pipe per unit. You must connect the air inlet pipe to a combustion air
inlet cap as specified in this section.
Combustion air supplied from outdoors must be free of contaminants (see the Combustion and Ventilation Air
section on page 10).
You must order the Horizontal Vent/Ducted Air Vent Kit for sidewall installation from the appliance manufacturer. See Table 2D
for kit numbers. Each kit includes a sidewall powered vent cap fan, proving switch, controls, combustion air inlet cap to supply air
to a single unit, the transition adapter to attach the field supplied single wall air inlet pipe to the unit and installation instructions.
Purchase flue pipe and air inlet pipe locally.
The sidewall air inlet cap supplied in the Horizontal Vent/Ducted Air Vent Kit is used to supply combustion air to a single hot water
supply boiler. Combustion air supply pipes from multiple units can not be combined into a single air inlet pipe and inlet point.
 WARNING
Only use the sidewall air inlet cap recommended by the appliance manufacturer. Using another sidewall air
inlet cap may result in operational problems and the spillage of flue products. Spillage of flue products can
cause personal injury or death due to carbon monoxide poisoning.
Venting of flue products
For venting flue products horizontally, follow all requirements in the installation instructions for sidewall venting.
Termination point for the flue products must follow the clearance requirements in the Sidewall Venting Termination section on
page 23.
For proper operation, a barometric damper is provided for Horizontal Vent/Ducted Air installations. The damper will help to
ensure a draft between negative 0.04 to 0.08 inches w.c.
TABLE - 2D
HORIZONTAL VENT/AIR KITS
MODEL
400
500
650
750
-*These kits include a barometric damper.
26
KIT
100131402
100131402
100131403
100131403
--
MODEL
1000
1250
1450
1800
2100
KIT
100131404*
100131405*
100131405*
100131406*
100131406*
Installation & Service Manual
2
Venting
(continued)
Direct Vent/Sealed Combustion - see page 15.
E
NOTICE
Before installing a venting system, follow all requirements found in the General Venting section.
This option uses sealed AL29-4C vent materials for the flue outlet piping and separate combustion air inlet piping.
This system terminates both the flue and combustion air inlet in the same pressure zone. The flue outlet and
combustion air intake may terminate at either a sidewall or the rooftop.
3'
MIN
12"
MIN
IMG00585
To use the optional Direct Vent system, you must install specific vent kits and venting materials. The following is
a detailed explanation of Direct Vent installation requirements, including the components used and vent kit part
numbers (reference Table 2E on page 28 for kit numbers).
Flue outlet piping
Venting Guidelines
If using this venting option, a sealed AL29-4C venting system for flue products is required on all models of this
appliance. This venting system operates with a positive pressure in the vent. The internal combustion air blower
generates this positive pressure which operates the combustion process and also exhausts the flue products from the
building.
This vent system has specific vent material and installation requirements. Only use listed sealed AL29-4C vent system
materials. Follow all installation requirements. See Table 2A, page 16 for proper pipe size for your unit.
Seal all vent joints and seams gas-tight.
Drain tee installation
A drain tee must be installed in the vent pipe to collect and dispose of any condensate that may occur in the vent system. The drain
tee must be installed as the first fitting after the horizontal ell on the top of the unit (see FIG. 2-9 on page 24). Plastic drain tubing,
sized per the vent manufacturer’s instructions, shall be provided as a drain line from the tee. The drain tubing must have a trap
provided by a 3" (7.6cm) diameter circular trap loop in the drain tubing. Prime the trap loop by pouring a small quantity of water
into the drain hose before assembly to the vent. Secure the trap loop in position with nylon wire ties. Use caution not to collapse
or restrict the condensate drain line with the nylon wire ties. The condensate drain must be routed to a suitable drain for disposal
of condensate that may occur in the direct vent system. Refer to the condensate drain installation instructions as supplied by the
manufacturer of the vent material.
 WARNING
Do not combine the flue from this unit with the vent from any other appliance. Do not combine flues from
multiple appliances into a common vent. The flue from this unit must be a dedicated stack.
Connect the flue vent directly to the flue outlet opening on the top of the unit. Make the connections from the unit vent to the
outside stack as direct as possible with no reduction in diameter. Provide adequate clearance to combustibles for the vent connector
and firestop. Follow the vent manufacturer’s instructions when installing sealed AL29-4C vents and accessories, such as firestop
spacers, vent connectors, thimbles, caps, etc.
Provide adequate clearance to combustibles for the vent connector and firestop.
When planning the venting system, avoid possible contact with plumbing or electrical wiring inside walls, ceilings, and floors.
Locate the unit as close as possible to chimney or gas vent.
When a vent system is disconnected for any reason, the flue must be reassembled and resealed according to the vent manufacturer’s
instructions.
The installed length of flue from the unit to the outside point of termination must not exceed 50 equivalent feet (15.2m). Subtract
5 feet (1.5m) of equivalent length for each 90° elbow. Subtract 2.5 feet (0.7m) of equivalent length for each 45° elbow.
Vertical DV venting termination
You must use the vent termination recommended by the vent manufacturer for vertical direct vent terminations. Follow all vertical
venting termination information for clearances and location under the Vertical Vent Termination Clearances and Location section
on pages 18 - 19.
27
Installation & Service Manual
2
Venting
Masonry chimney installation
Do not use a standard masonry chimney to directly vent the combustion products from this unit.
To use a masonry chimney, the chimney must use a sealed, corrosion-resistant liner system. Sealed, corrosion-resistant liner
systems (single-wall, double-wall, flexible, or rigid) must be rated for use with a high efficiency, positive pressure vent system.
Corrosion-resistant chimney liner systems are typically made from a high grade stainless steel such as AL29-4C. The liner must be
properly sized and fully sealed throughout the entire length. Both the top and bottom of the masonry chimney must be capped
and sealed to provide a dead air space around the liner.
 WARNING
NOTICE
Do not vent this unit into a masonry chimney without a sealed stainless steel liner system. Any breaks, leaks,
or damage to the masonry flue/tile will allow the positive-pressure flue products to leak from the chimney and
into occupied living spaces. This could cause serious injury or death due to carbon monoxide poisoning and
other harmful flue products.
Check with local code officials to determine code requirements or the advisability of using a masonry chimney
with a sealed corrosion-resistant liner system.
Horizontal DV venting termination
Horizontal venting uses the unit’s internal combustion air blower to force the flue products out of the horizontally-terminated flue.
You must purchase a horizontal direct vent kit from the appliance manufacturer to ensure proper operation. When installing
the vent cap, the wall opening must provide an air space clearance of 2 inches (5.1cm) around the flue pipe. The diameter of the
opening for installation of the sidewall cap will be 4 inches (10.2cm) larger (minimum) than the nominal diameter of the installed
vent pipe to the horizontal vent cap.
Install the horizontal vent cap from the outside. Mount the vent cap to the wall using four screws or wall anchors. Seal under the
screw heads with caulking. Install the Category IV vent pipe from the unit to the vent cap. See detailed instructions packed with
the horizontal direct vent kit.
Horizontal Vent Termination Clearances and Location
Follow all sidewall venting termination information for clearances and location under Sidewall Vent Termination Clearances and
Location, page 23.
TABLE - 2E
MODEL
400
500
650
750
--
HORIZONTAL
KIT*
100131411
100131411
100131412
100131412
--
DIRECT VENT KITS
VERTICAL
MODEL
KIT*
100131398
1000
100131398
1250
100131399
1450
100131399
1800
-2100
HORIZONTAL
KIT*
100131413
100131414
100131414
100131415
100131415
VERTICAL
KIT*
100131400
100131401
100131401
100131401
100131401
*These kits include a DV box adapter, air inlet cap, and a sidewall vent termination. The VDK kits include a DV box adapter and an air inlet cap.
Combustion air inlet piping
The Direct Vent system requires the installation of a pipe to supply combustion air from the outdoors directly to the unit. Make
sure the combustion air inlet is in the same pressure zone as the vent terminal.
In cold climates, use a Type-B double-wall vent pipe or an insulated single wall pipe for combustion air. This will help prevent
moisture in the cool incoming air from condensing and leaking from the inlet pipe.
 CAUTION
28
Units that are shut down or will not operate may experience freezing due to convective airflow in the air inlet
pipe.
Installation & Service Manual
2
Venting
(continued)
Length of air inlet pipe
The installed length of air inlet pipe from the unit to the outside air inlet cap must not exceed 50 equivalent feet (15.2m). Subtract
5 feet (1.5m) of equivalent length for each 90° elbow. Subtract 2.5 feet (0.7m) of equivalent length for each 45° elbow.
Do not exceed the limits for the combustion air inlet piping lengths.
Connecting the air inlet pipe to the unit
Connect the air inlet piping directly to the unit by attaching it to the DV box adapter. The DV box adapter is included in the direct
vent kits. The combustion air inlet area of the unit is located at the right rear corner of the unit. This unit uses a simple air filter
to ensure clean air is used for the combustion process. Attach the DV box adapter over the air filter (see FIG. 2-10). Align screw
holes on the DV box adapter with the screw holes surrounding the air filter hanger. Insert sheet metal screws and tighten firmly.
For venting versatility, you can move the air filter assembly and DV box adapter to the right side of the unit. Remove the metal
panel on the unit’s right side (see FIG. 2-11). Remove the filter/bracket assembly from the rear of the unit. Attach the filter/bracket
assembly and DV box adapter to the right side opening using the pre-drilled screw holes. Make sure you attach the metal panel to
the rear combustion air opening of the unit.
The DV box adapter has an air inlet pipe mounting ring. Connect combustion air inlet piping to the direct vent box mounting ring.
VERTICAL DV BOX ADAPTER
HORIZONTAL DV BOX ADAPTER
Figure 2-10_Attaching DV Box Adapter to Unit
Figure 2-11_Moving Air Filter Assembly & DV Box Adapter
Air inlet piping materials
The air inlet pipe(s) must be sealed. Select air inlet pipe material from the following specified materials.
• PVC, CPVC, or ABS*
• Dryer vent or sealed flexible duct (not recommended for rooftop air inlet)
• Galvanized steel vent pipe with joints and seams sealed as specified below
• Type-B double-wall vent with joints and seams sealed as specified below.
* Plastic pipe may require an adapter (not provided) to transition between the air inlet connection on the unit and the plastic air
inlet pipe.
Use only vent or air intake materials specified in this manual. Follow vent pipe manufacturer’s instructions.
Failure to do so can result in property damage, personal injury, or death. Mixing of venting materials will void
the warranty and certification of this unit.
Sealing Type-B double-wall vent pipe or galvanized vent pipe
 WARNING
Follow the steps below to properly seal Type-B double-wall vent pipe or galvanized vent pipe.
1. Seal all joints and seams of the air inlet pipe using either aluminum foil duct tape meeting UL Standard 723 or 181 A-P or a
high quality UL Listed silicon sealant such as those manufactured by Dow Corning or General Electric.
2. On horizontal runs, do not install vent pipe with seams pointing down. Position vent pipe so that the seams are on the top side
of the vent pipe.
3. Secure all joints with a minimum of three sheet metal screws or pop rivets. Apply aluminum foil duct tape or silicone sealant
to all screws or rivets installed in the vent pipe.
4. Ensure that the air inlet pipes are properly supported.
Sealing PVC, CPVC, ABS, dryer vent, and flex duct vent pipe
1. Clean the PVC, CPVC, or ABS air inlet pipe using the pipe manufacturer’s recommended solvents. Seal the pipe joints using
standard commercial pipe cement.
29
Installation & Service Manual
2
Venting
2. For PVC, CPVC, ABS, dryer vent, or flex duct air inlet piping, use a silicone sealant to ensure a proper seal at the unit inlet and
the air inlet cap.
3. For Dryer vent or flex duct, also use a screw-type clamp to attach the inlet vent material to the unit inlet and the air inlet cap.
Properly sealing the air inlet pipe ensures that combustion air will be free of contaminates and supplied in proper volume.
4. Ensure that the air inlet pipes are properly supported.
 WARNING
Properly seal all joints and seams in the inlet vent piping system. Failure to do so may result in flue gas
recirculation, spillage of flue products, and carbon monoxide emissions. Carbon monoxide poisoning can
cause severe personal injury or death.
Vertical and sidewall combustion air inlet
NOTICE
To prevent recirculation of flue products into the combustion air inlet, follow all instructions in this section.
 WARNING
Locate and install the combustion air inlet termination correctly. Failure to do so can allow the discharge
of flue products to be drawn into the combustion process. This can result in incomplete combustion and
potentially hazardous levels of carbon monoxide in the flue products. This will cause operational problems
and the spillage of flue products. Spillage of flue products can cause personal injury or death due to carbon
monoxide poisoning.
You must locate the combustion air cap and the flue gas outlet on the same rooftop surface (vertical direct vent system) or sidewall
surface (horizontal direct vent system) and in the same pressure zone as the vent termination. Follow all clearance requirements
listed on this page.
Purchase and assemble the combustion air inlet cap to protect the air inlet from wind and weather.
Alternatively, assemble the combustion air inlet cap for vertical rooftop air inlet from items purchased locally. The air inlet cap
consists of two 90° elbows installed to the air inlet pipe (see FIG. 2-12). Install the first 90° elbow on the rooftop at the highest
vertical point of the air inlet pipe. Install the second 90° elbow on the horizontal outlet of the first elbow. The outlet of the second
90° elbow will be pointing down. You may use a 90° elbow and a 90° straight elbow to make this assembly. If you use a straight
piece of pipe between the two 90° elbows, it should not exceed 6" (51mm) in length.
6"
MAX
For horizontal direct vent termination of combustion air, you
must use the termination cap from the appliance manufacturer.
The sidewall air inlet cap is available as part of a direct vent kit.
See Table 2E, page 28 for Horizontal Direct Vent Kits.
Vertical Combustion Air Inlet Clearances
You must locate the air inlet termination elbow at least 12"
(30cm) above the roof or above normal snow levels.
If the air inlet cap is within a 10-foot (3.05m) radius of the flue
outlet, the point of termination for the combustion air inlet
cap must be at least 3 feet (0.91m) below the point of flue gas
termination (vent cap).
Figure 2-12_Vertical Rooftop Air Inlet
Do not install the combustion air inlet cap closer than 10 feet
(3.05m) from an inside corner of an L-shaped structure.
Horizontal combustion air inlet clearances
You must locate the horizontal air inlet termination point at least 12" (30cm) above grade and above normal snow levels.
If the air inlet cap is within a 10-foot (3.05m) radius of the flue outlet, the point of termination for the combustion air inlet cap
must be at least 3 feet (0.91m) below the point of flue gas termination (vent cap). Do not install the horizontal combustion air inlet
cap above the flue outlet.
Do not install the combustion air inlet cap closer than 10 feet (3.05m) from an inside corner of an L-shaped structure.
Multiple sidewall direct vent installations
You must locate the horizontal air inlet termination points at least 12" (30cm) above grade and above normal snow levels. The
combustion air inlet caps for multiple appliance installations must maintain the same minimum clearance from the closest flue vent
cap as specified in single appliance installations. You may install multiple flue outlet caps side-by-side and multiple combustion
air inlet caps side-by-side, but the air inlet must always be at least 3 feet (0.91m) horizontally and 3 feet (0.91m) below the closest
flue outlet. Do not install combustion air inlet caps above the flue outlets.
Maintain all clearances and installation requirements for multiple appliance installations.
30
Installation & Service Manual
2
F
Venting
(continued)
Outdoor installation - see page 15.
Before installing a venting system, follow all requirements found in the General Venting section.
NOTICE
Units are self-venting and can be used outdoors when installed with the optional outdoor cap. This cap mounts directly to the top
of the unit and covers the flue outlet and combustion air inlet openings. No additional vent piping is required.
Only install outdoor models outdoors and only use the vent cap supplied by the appliance manufacturer.
Personal injury or product damage may result if any other cap is used or if an outdoor model is used indoors.
Properly install all covers, doors and jacket panels to ensure proper operation and prevent a hazardous
condition.
Combustion air supply must be free of contaminants (see Combustion and Ventilation Air, page 10). To prevent recirculation of
the flue products into the combustion air inlet, follow all instructions in this section.
 WARNING
Outdoor vent/air inlet location
Keep venting areas free of obstructions. Keep area clean and free of combustible and flammable materials. Maintain a minimum
clearance of 3" (76mm) to combustible surfaces and a minimum of 36" (915mm) clearance to the air inlet. To avoid a blocked air
inlet or blocked flue condition, keep the outdoor cap air inlet, flue outlet and drain slot clear of snow, ice, leaves, debris, etc.
Do not install outdoor models directly on the ground. You must install the outdoor unit on a concrete, brick, block, or other noncombustible pad.
Do not locate unit so that high winds can deflect off of adjacent walls, buildings or shrubbery causing recirculation. Recirculation
of flue products may cause operational problems, bad combustion or damage to controls. Locate unit at least 3 feet (0.91m) from
any wall or vertical surface to prevent wind conditions from affecting performance.
Multiple unit outdoor installations require 48" (1.22m) clearance between each vent cap. Locate outdoor cap at least 48" (1.22m)
below and 48" (1.22m) horizontally from any window, door, walkway or gravity air intake.
Locate unit at least 10 feet (3.05m) away from any forced air inlet.
Locate unit at least 3 feet (0.91m) outside any overhang.
Clearances around outdoor installations can change with time. Do not allow the growth of trees, shrubs or other plants to obstruct
the proper operation of the outdoor vent system.
Do not install in locations where rain from building runoff drains will spill onto the unit.
3'
MIN
Flue gas condensate can freeze on exterior walls or on the vent
cap. Frozen condensate on the vent cap can result in a blocked
flue condition. Some discoloration to exterior building or unit
surfaces can be expected. Adjacent brick or masonry surfaces
should be protected with a rust resistant sheet metal plate.
The outdoor vent cap kit
3'
MIN
3'
MIN
3'
MIN
The optional outdoor vent cap kit is available from the
appliance manufacturer. The outdoor cap part numbers are
listed by model number. See Table 2F for kit numbers.
Install the outdoor vent cap on the rear of the unit. Complete
installation instructions are included with the outdoor vent
cap kit.
IMG00588
Figure 2-13_Outdoor vent cap installed
TABLE - 2F
MODEL
400
500
650
750
--
OUTDOOR VENT CAP KITS
KIT* WITH
KIT* WITH
MODEL
PUMP COVER
PUMP COVER
100131387
1000
100131389
100131387
1250
100131390
100131388
1450
100131391
100131388
1800
100131392
-2100
100131392
*These kits include an outdoor vent cap and gasket.
31
Installation & Service Manual
3
Gas connections
Connecting to gas supply
Verify that the appliance is supplied with the type of gas
specified on the rating plate. This appliance is configured
for operation up to 4,500 feet altitude. Consult factory for
installations above 4,500 feet elevation.
Inlet gas pressure: Measured at the inlet pressure tap on the
appliance gas manifold. The pressure tap is located upstream of
the combination gas valve(s) (FIG. 3-3 on page 34).
Install a manual main gas shutoff valve, outside of the unit gas
connection within six feet of the unit in accordance with the
requirements of the National Fuel Gas Code, ANSI Z223.1.
You must provide a sediment trap (drip leg) in the inlet of the
gas connection to the unit.
It is the installer’s responsibility to supply
the sediment trap (drip leg).
NOTICE
Do not block access to the electrical cover
plate when installing the sediment trap.
The sediment trap must be a minimum of
12 inches from the appliance.
CAUTION
See Table 3A for maximum and minimum inlet pressures. Do
not exceed the maximum. Minimum inlet pressure is for the
purpose of input adjustment.
The combination gas valves have an integral vent limiting
device and do not require venting to atmosphere, outside the
building. The unit will not operate properly if the reference hose
is removed or a vent to atmosphere is installed.
TABLE 3A
INLET GAS PRESSURE
MODEL
400 - 2100
NATURAL
Max.
Min.
w.c.
w.c.
14.0
4.5
LP
Max.
w.c.
14.0
Min.
w.c.
8.0
Manifold pressure: The gas regulator on the unit’s
combination gas valve is adjustable to supply proper manifold
pressure for normal operation. See the Genesis Service Manual
for net manifold pressure settings.
If you must adjust regulator pressure, follow the instructions
under Gas Manifold Pressure Adjustment in the Genesis Service
Manual. Do not increase regulator pressure beyond specified
pressure setting.
Gas pressure test
1.
The appliance must be disconnected from the gas
supply piping system during any pressure testing of that
system at a test pressure in excess of 1/2 PSIG (3.5 kPa).
2.
The appliance must be isolated from the gas supply
piping system by closing a manual shutoff valve during
any pressure testing of the gas supply piping system at
test pressures equal to or less than 1/2 PSIG (3.5 kPa).
3.
Optional gas controls may require routing of bleeds and vents
to the atmosphere, outside the building when required by local
codes.
Gas connection
All gas connections must be made with pipe joint compound
resistant to the action of liquefied petroleum (L.P.) and natural
gases. All piping must comply with local codes and ordinances.
Piping installations must comply with approved standards and
practices.
1. Make sure gas line is a separate line direct from the meter
unless the existing gas line is of sufficient capacity. Verify
pipe size with your gas supplier.
USE WRENCH
TO HOLD
SUPPLY PIPE
12"
MIN
COUPLING
UNION
MANUAL MAIN
SHUT OFF
VALVE
The appliance and its gas connection must be leak
tested before placing it in operation.
NIPPLE
Gas piping
To safely operate this unit, you must properly size the gas
supply piping. See Tables 3B through 3D for piping and
fitting requirements. Gas pipe size may be larger than heater
connection.
For ease of service, install a union.
32
CAP
IMG00589
Figure 3-1_Gas Line Connection
NOTICE
If an inline high gas pressure regulator is
used, it MUST BE of the lockup type and
be located a minimum of 10 feet from the
appliance. Failure to do so may result in
insufficient gas volume supplied to the
appliance.
Installation & Service Manual
3
Gas connections
(continued)
2. Use new, properly threaded black iron pipe free from
chips. If you use tubing, make sure the ends are cut
square, deburred and clean. Make all tubing bends smooth
and without deformation. Avoid flexible gas connections.
Internal diameter of flexible lines may not provide unit with
proper volume of gas.
3. Install a manual main gas shutoff valve at the unit’s gas inlet,
outside of the unit.
4. Run pipe or tubing to the unit’s gas inlet. If you use tubing,
obtain a tube to pipe coupling to connect the tubing to the
unit’s gas inlet.
5. Install a sediment trap in the supply line to the unit’s gas
inlet (see FIG. 3-1).
6. Apply a moderate amount of good quality pipe compound
(do not use Teflon tape) to pipe only, leaving two end
threads bare.
8. Connect gas pipe to inlet of unit. Use wrench to support gas
manifold on the unit.
9. For L.P. gas, consult your L.P. gas supplier for expert
installation.
10. Ensure that all air is completely bled from the gas line before
starting the ignition sequence. Start up without properly
bleeding air from the gas line may require multiple reset
functions of the ignition control module to achieve proper
ignition.
Do not have any open flame in proximity to
 WARNING the gas line when bleeding air from the gas
line. Gas may be present.
Gas train and controls
The gas train and controls assembly
provided on this unit have been tested under
the applicable American National Standard
to meet minimum safety and performance
criteria such as safe lighting, combustion
and safety shutdown operation.
400 MODEL
400
500
650
750
1000
1250
1450
1800
2100
0 - 50
1 1/4"
1 1/4"
1 1/2"
1 1/2"
2"
2"
2 1/2"
2 1/2"
2 1/2"
51 - 100 101 - 200 201- 300 301- 500
1 1/4"
1 1/2"
2"
2"
1 1/2"
2"
2"
2 1/2"
2"
2"
2 1/2"
2 1/2"
2"
2"
2 1/2"
3"
2"
2 1/2"
2 1/2"
3"
2 1/2"
2 1/2"
3"
3"
2 1/2"
3"
3"
3 1/2"
3"
3"
3 1/2"
3 1/2"
3"
3"
3 1/2"
4"
TABLE - 3C
FITTINGS TO EQUIVALENT STRAIGHT PIPE
Diameter
Pipe
3/4
(inches)
Equivalent
length of
2
Straight Pipe
(feet)
1
2
1 1/4 1 1/2
3
4
2
3
4
5
5
10
14
20
Combination gas valves
These units fire in multiple stages of burner input. Each stage
of burner operation has a combination gas valve(s) to cycle
the gas supply on and off and regulate gas to the burners. Each
combination valve consists of a gas regulator and two valve seats
to meet the requirements for redundant gas valves. The valve
has a gas control knob that must remain in the open position
at all times when the unit is in service. The gas control valve
has pressure taps located on the inlet and discharge sides of the
valve. Manifold pressure is adjusted using the regulator located
on the valve. A manifold gas pressure tap for each burner stick
is located on the discharge side of the valve.
The manifold pressure is preset at the factory and adjustment
is not usually required. If you must adjust regulator pressure,
follow the instructions in the Genesis Service Manual.
COMBINATION
VALVE
COMBINATION
VALVE
Distance from Meter (in feet)
MODEL
For each elbow or tee, add equivalent straight pipe to total length from Table 3C.
7. Remove seal over gas inlet to unit.
NOTICE
TABLE 3B
SUGGESTED GAS PIPE SIZE FOR
SINGLE UNIT INSTALLATIONS
2100 MODEL
Venting of combination gas valves
The combination gas valve/regulator used on all units is
equipped with an integral vent limiting orifice per ANSI Z21.78.
The vent limiter ensures that the volume of gas emitted from
the valve in the event of a failed gas diaphragm does not exceed
the maximum safe leakage rate allowed by agency requirements.
DOWNSTREAM
TEST VALVE
TO BURNERS
DOWNSTREAM
TEST VALVE
TO BURNERS
Figure 3-2_Typical Hot Water Supply Boiler Gas Train
Drawing
33
Installation & Service Manual
3
Gas connections
Combination gas valve/regulators equipped with integral vent
limiters are not required to have vent or relief lines piped to
the outdoors. The termination of the vent limited opening on
the combination gas valve/regulator complies with the safety
code requirements of CSD-1, CF-190(a) as shipped from the
appliance manufacturer without the installation of additional
vent lines.
Checking gas supply pressure
Use the following procedure to check gas supply pressure.
1. Turn the main power switch to the “OFF” position.
2. Turn gas valve knobs to the “OFF” position.
3. Shut off gas supply at the field-installed manual gas cock in
the gas piping to the unit. If fuel supply is L.P. gas, shut off
gas supply at the tank.
4. Remove the 1/8" hex plug, located on the “inlet” side of the
gas valve. You may also use a tapping on the field-installed
main manual gas cock or gas piping. Install a fitting in the
inlet pressure tapping suitable to connect to a manometer
or magnehelic gauge. Range of scale should be 14" w.c. or
greater to check inlet pressure.
5. Turn on gas supply at the manual gas cock, turn on L.P. gas
at the tank if required.
6. Turn the power switch to the “ON” position.
7. Turn the gas valve knobs to the “ON” position. Set the
electronic temperature control or thermostat to call for
heat.
8. Observe the gas supply pressure as all burners are firing.
Ensure that inlet pressure is within the specified range.
See Connecting To Gas Supply, page 32 for minimum and
maximum gas supply pressures.
9. If gas pressure is out of range, contact gas utility, gas
supplier, qualified installer or service agency to determine
necessary steps to provide proper gas pressure to the
control.
10. If gas supply pressure is within normal range, turn the
power switch to the “OFF” position.
11. Turn gas valve knobs to the “OFF” position.
12. Shut off gas supply at the manual gas cock in the gas piping
to the unit. If fuel supply is L.P. gas, shut off gas supply at
the tank.
13. Remove the manometer and related fitting from the “inlet”
side of the gas valve, replace 1/8" hex plug in gas valve and
tighten.
14. Turn on gas supply at the manual valve, turn on L.P. gas at
the tank if required.
15. Turn the power switch to the “ON” position.
16. Turn the gas valve knob to the “ON” position.
17. Set the electronic temperature control or thermostat to call
for heat.
 WARNING
After completing any testing on the gas
system, leak test all gas connections. Apply
a soap/water solution to all gas connections
while main burners are operating. Bubbles
forming indicate a leak. Repair all leaks at
once. Do not operate this unit with a leak in
the gas train, valves or related piping.
Check burner performance by cycling the system while you
observe burner response. Burners should ignite promptly.
Flame pattern should be stable, see Burner Flames in the
Genesis Service Manual. Turn system off and allow burners to
cool, then cycle burners again to ensure proper ignition and
flame characteristics.
SUPPLY INLET
PRESSURE TAP
GAS VALVE
CONTROL KNOB
INLET
OUTLET
MANOMETER
IMG00590
Figure 3-3_Measuring
Combination Gas Valve
Gas
Supply
Pressure
at
TABLE - 3D
GAS PIPING SIZE CHART
Nominal
Iron Pipe
Size
Inches
10
20
30
40
50
60
70
80
90
100
125
150
175
3/4
369
256
205
174
155
141
128
121
113
106
95
86
79
1
697
477
384
328
292
267
246
256
210
200
179
164
149
1 1/4
1,400
974
789
677
595
543
502
472
441
410
369
333
308
830
769
707
Length of Pipe in Straight Feet
1 1/2
2,150
1,500
1,210
1,020
923
666
636
564
513
472
2
4,100
2,820
2,260
1,950
1,720
1,560 1,440 1,330
1,250
1,180
1,100
974
871
2 1/2
6,460
4,460
3,610
3,100
2,720
2,460 2,310 2,100
2,000
1,900
1,700 1,540 1,400
3
11,200
7,900
6,400
5,400
4,870
4,410 4,000 3,800
3,540
3,300
3,000 2,720 2,500
4
23,500 16,100 13,100 11,100 10,000 9,000 8,300 7,690
7,380
6,870
6,150 5,640 5,130
34
Maximum
Capacity of Pipe
in Thousands of
200 Btu/hr per hour
for gas pressures
74
of 14 Inches
138
Water Column
287 (0.5 PSIG) or less
and a pressure
441
drop of 0.5 Inch
Water Column
820
(Based on NAT
1,300 GAS, 1025 Btu/hr
2,340 per Cubic Foot
of Gas and 0.60
4,720 Specific Gravity)
Installation & Service Manual
4
Water connections
Inlet and outlet connections
Initial set-up of maximum water flow
For ease of service, install unions on the water inlet and
water outlet of the unit. The connection to the unit marked
“Inlet” on the header should be used for return from the
system. The connection on the header marked “Outlet” is
to be connected to the supply side of the system.
On initial start-up of the Genesis, the maximum water flow to
the heat exchanger must be checked and manually limited with
a valve or bypass before normal operation begins.
 CAUTION
2" NPT
WATER
INLET
2" NPT
WATER
OUTLET
IMG00591
INSPECTION
PLUGS
Figure 4-1_Water Connections - Models 400 - 750
2-1/2" NPT
WATER
INLET
An appliance allowed to operate at return
temperatures below the specified minimum
setting may experience problems with
the operating controls, safety switches,
obstruction of the flue gas passages on the
heat exchanger, incomplete combustion
and possible flue gas spillage. Sustained
operation at lower than specified water
temperatures (140°F) may cause hazardous
conditions that may result in personal injury
or non-warrantable damage to the appliance.
Water flow switch
A water flow switch is factory installed in the outlet on all hot
water supply boilers. The flow switch must prove water flow
before a trial for ignition can begin. The flow switch requires
a minimum flow of 15 - 18 GPM on Models 400 - 750 and
26 GPM on Models 1000 - 2100 to make the flow switch and
start burner operation. A water flow switch meets most code
requirements for a low water cutoff device on hot water supply
boilers requiring forced circulation for operation.
Low water cutoff
(if equipped)
If this unit is installed above radiation level, a low water cutoff
device must be installed at the time of hot water supply boiler
installation. An electronic low water cutoff is available as a
factory supplied option on all models. The low water cutoff
should be inspected every 6 months.
2-1/2" NPT
WATER
OUTLET
IMG00592
INSPECTION
PLUGS
Figure 4-2_Water Connections - Models 1000 - 2100
Relief valve
This unit is supplied with a safety relief valve(s) sized in
accordance with ASME Boiler and Pressure Vessel Code,
Section IV (“Rules for Construction of Heating Boilers”). The
relief valve(s) is installed in the vertical position and mounted
in the hot water outlet. No valve is to be placed between
the relief valve and the unit. To prevent water damage, the
discharge from the relief valve shall be piped to a suitable floor
drain for disposal when relief occurs. No reducing couplings
or other restrictions shall be installed in the discharge line. The
discharge line shall allow complete drainage of the valve and
line. Relief valves should be manually operated at least once a
year.
 CAUTION
Avoid contact with hot discharge water.
35
Installation & Service Manual
4
Water connections
Piping of the hot water supply boiler
system
Before beginning the installation, consult local codes for specific
plumbing requirements. The installation should provide unions
and valves at the inlet and outlet of the hot water supply boiler
so it can be isolated for service. An air separation device must
be supplied in the installation piping to eliminate trapped air in
the system. Locate a system air vent at the highest point in the
system. The system must also have a properly sized expansion
tank installed. Typically, an air charged diaphragm-type
expansion tank is used. The expansion tank must be installed
close to the hot water supply boiler and on the suction side of
the system pump to ensure proper operation.
 CAUTION
Example: The hot water supply boiler inlet temperature is
140°F (60°C) and the hot water supply boiler outlet temperature
is 160°F (71.1°C). This means that there is a 20°F (11.1°C)
temperature rise across the hot water supply boiler.
Figure 4-3_Presssure Drop Chart - Models 400 - 750
PRESSURE DROP IN FEET HEAD
Hot water supply boiler installations
The hot water supply boiler system should
not be operated at less than 12 PSIG.
Hot water piping must be supported by suitable hangers or
floor stands, NOT by the hot water supply boiler. Copper
pipe systems will be subject to considerable expansion and
contraction. Rigid pipe hangers could allow the pipe to slide
in the hanger resulting in noise transmitted into the system.
Padding is recommended on rigid hangers installed with a
copper system. The hot water supply boiler pressure relief valve
must be piped to a suitable floor drain.
FLOW IN GALLONS PER MINUTE
Figure 4-4_Pressure Drop Chart - Models 1000 - 2100
Models 1000 - 2100
Water connections
Models 400 - 750 have 2" NPT inlet and outlet connections
and Models 1000 - 2100 have 2 1/2" NPT inlet and outlet
connections.
Field installed reducing bushings must not
 CAUTION
be used.
Any reduction in pipe size may decrease flow resulting in
high water temperatures, noise, flashing to steam, and nonwarrantable heat exchanger damage.
It is important to guarantee that adequate flow is provided to
properly dissipate heat from the unit and also ensure that flow
through the unit does not exceed the maximum recommended
flow rate of 55 GPM for Models 400 - 750 and 90 GPM for
Models 1000 - 2100 for a hot water supply boiler equipped with
a copper heat exchanger.
Circulator pump requirements
This is a low mass, high efficiency hot water supply boiler which
must have adequate flow for quiet, efficient operation. Pump
selection is critical to achieve proper operation. A pump should
be selected to achieve proper system design water temperature
rise. Two heat exchanger head-loss charts (FIG.’s 4-3 and 4-4)
are provided to assist in proper pump selection. A System
Temperature Rise Chart (Table 4B on page 37) is also provided.
This table provides GPM and hot water supply boiler head-loss
at various temperature rises for each model based on Btu/hr
input. Temperature rise is the difference in hot water supply
boiler inlet temperature and hot water supply boiler outlet
temperature while the hot water supply boiler is firing.
36
Circulator pump specifications
1.
Maximum operating pressure for the pump must exceed
system operating pressure.
2. Maximum water temperature should not exceed the
nameplate rating.
3. A properly sized expansion tank must be installed near the
hot water supply boiler.
Circulator pump operation
The hot water supply boiler pump must run when the unit
is firing. Separate supply circuits can be provided or the two
circuits (pump and controls) can be combined for connection
to one circuit, properly sized for both.
Pump delay operation
A pump delay operation feature is provided. The hot water
supply boiler’s circulating pump will cycle on at each call for
heat, before the unit fires and will continue to run as long as the
call for heat is active. After the call for heat, the unit will shut
down and the pump will continue to run for a period of time to
remove the residual heat from the heat exchanger.
Installation & Service Manual
4
Water connections
(continued)
Pump minimum delta T (T)
A pump minimum T feature is provided in addition to the
pump delay. After a call for heat, the unit will shut down and
the pump will continue to run as long as the T is above the
preset value. The minimum T can be set to ON, 1 to 20°F or
OFF. If set to ON, the pump will run continuously whether or
not there is a call for heat. If set to a value of 1 to 20°F, the pump
will run until the T drops below the set value plus the pump
delay time. Factory default is 5°F. If set to OFF, the pump will
run for 30 seconds after the call for heat.
Maximum delta T (T)
A maximum T feature is provided. If enabled, this will allow
the controller to monitor the hot water supply boiler’s T to
allow it to display a Max T error and enable the alarm circuit
should the programmed value be exceeded. The maximum T
can be set to a value from 80°F to 20°F or OFF. If set to OFF it
will disable this feature. This can be useful to alert the user to
either poor flow or hard water issues. Factory default is OFF.
Pump installation and maintenance
For installation and maintenance information on the circulator
pump, refer to the pump manufacturer’s instructions provided
in the instruction package.
Hot water supply boiler flow rate
 CAUTION
The maximum flow rate for Models 400 - 750
is 55 GPM and 90 GPM on Models 1000 2100. Do not exceed the maximum flow rate
of the hot water supply boiler.
If higher flow rates are required through the
hot water supply boiler, an optional CuproNickel heat exchanger is available. When
using a Cupro-Nickel heat exchanger, GPM
can be increased by 30 percent. Consult the
factory for specific application requirements.
Flow rate can be determined by measuring the temperature rise
through the hot water supply boiler.
Minimum water temperatures
Inlet water temperatures below the specified minimum of
140°F (60°C) can excessively cool the products of combustion
resulting in condensation on the heat exchanger. Condensation
on the heat exchanger can cause operational problems, bad
combustion, sooting, flue gas spillage and reduced service life of
the related components.
 CAUTION
A hot water supply boiler allowed to
operate at set point temperatures below the
specified minimum settings may experience
operational problems with the operating
controls and safety switches, obstruction of
the flue gas passages on the heat exchanger,
incomplete combustion and possible flue gas
spillage. Operation at lower than specified
water temperatures may cause hazardous
conditions that result in non-warrantable
damage to the appliance.
TABLE - 4A
MAXIMUM FLOW FOR HEATING HOT WATER SUPPLY
BOILER
The maximum flow rate through the hot water supply boiler
with a copper heat exchanger must not exceed the following:
Model
Maximum Flow
400 - 750
55 GPM
1000 - 2100
90 GPM
If higher flow rates are required through the hot water supply
boiler, an optional Cupro-Nickel heat exchanger is available.
Consult the factory for specific application requirements.
Low system water volume
System run time is very important to the overall operating
efficiency of the unit. Short cycling of the unit creates problems
with condensation in the vent stack, condensation on the
heat exchanger, system temperature spikes, and mechanical
component failures. To prevent short cycling of the hot water
supply boiler, it is important to limit the cycles to six or fewer
per hour.
TABLE - 4B
ACCEPTABLE TEMPERATURE RISE
Model
400
500
650
750
1000
Min ∆ °F
12
15
20
23
19
Max ∆ °F
18
20
25
30
25
1250
24
30
1450
27
35
1800
34
40
2100
39
42
Typical hot water supply boiler installations
General plumbing rules:
1. Check all local codes.
2. For serviceability of the hot water supply boiler, always
install unions.
3. Always pipe pressure relief valve to an open drain.
4. Locate system air vents at highest point of system.
5. Support all water piping.
37
Installation & Service Manual
5
Electrical connections
Connecting to electrical supply
This unit is wired for 120 VAC service. The unit, when
installed, must be electrically grounded in accordance with
the requirements of the authority having jurisdiction or in
the absence of such requirements, with the latest edition of
the National Electrical Code ANSI/NFPA No. 70. When
the unit is installed in Canada, it must conform to the
CAE C22.1, Canadian Electrical Code, Part 1 and/or local
Electrical Codes.
1.
Use only Type-T wire [63°F (35°C) rise] on all wiring
between the unit and field-installed devices.
2.
Enclose line voltage wire exterior to the unit in approved
conduit or approved metal-clad cable.
3.
The pump must run continuously when the unit is
being fired (hot water supply boilers must use the
pump delay if the pump is to be cycled. See Freeze
Protection, page 44 when cycling the pump). Hot water
supply boilers use the pump delay as standard in
accordance with ASHRAE 90.1 requirements.
4.
5.
 WARNING
ELECTRICAL SHOCK HAZARD – For your
safety, turn off electrical power supply before
making any electrical connections to avoid
possible electric shock hazard. Failure to do
so can cause severe personal injury or death.
 CAUTION
Label all wires prior to disconnection when
servicing controls. Wiring errors can cause
improper and dangerous operation. Verify
proper operation after servicing.
Installation must comply with:
1. National Electrical Code and any other national, state,
provincial, local codes, or regulations.
2. In Canada, CSA C22.1 Canadian Electrical Code Part 1,
and any local codes.
TABLE - 5A
AMP DRAW DATA
Model Controls Blower
Approximate Total
Amps @ 120 VAC
To avoid serious damage, do not energize the unit until the
system is filled with water.
400
3.6
2.7
5.8
12.1
500
3.6
2.7
5.8
12.1
Provide the unit with proper overload protection.
650
5.4
3.4
5.8
14.6
750
5.4
3.4
5.8
14.6
1000
7.3
3.2
7.4
17.9
NOTICE
Do not block access to the electrical
cover plate when installing electrical
conduit.
1250
1450
1800
2100
7.3
3.2
7.4
17.9
7.3
6.7
7.4
21.4
7.3
6.7
7.4
21.4
7.3
6.7
7.4
21.4
*Standard Pump Supplied with HWSBs
Figure 5-1_Control panel location
IGNITION
MODULE
TRANSFORMER
150 VA
CONNECTION
BOARD
CIRCUIT
BREAKER
MANUAL
RESET
HIGH LIMIT
GROUND
SCREW
TERMINAL
STRIP
IMG00593
38
Pump
FLA*
24 VAC
RELAY
ON/OFF
SWITCH
24 VAC
RELAY
Installation & Service Manual
5
Electrical connections
Line voltage connections
1. Connect 120 VAC power wiring to the line voltage
terminal strip in the junction box, as shown in FIG. 5-2.
2. Provide and install a fused disconnect or service switch
(15 AMP recommended) as required by the code (see
FIG. 5-2).
3. To activate a system pump, wire as shown in FIG. 5-2. If
the motor is larger than 1 HP, you must install a contactor.
UNIT
SUPPLY
L
N
UNIT PUMP
SUPPLY
G
L
N
G
D
I
S
C
O
N
N
E
C
T
D
I
S
C
O
N
N
E
C
T
External EMS connection to terminal
strip for stage firing control of burners
This unit is equipped with a factory installed terminal strip
for connection of an energy management system (EMS) to the
burner stages. The EMS terminal strip is located in the unit’s
control panel. Ensure that all wiring used for connection to
this terminal strip is properly sized per the recommendations
in TABLE 5A. When connecting an EMS to this terminal
strip to sequence on each stage of burner operation, the unit’s
electronic control should be set to Sequencer Mode 3 to act as
an additional high limit control. This will prevent problems
between the setpoints of the EMS and the hot water supply
boiler’s internal controller.
Terminal strip connection options (reference figures
on page 40)
Figure 5-4 shows the position of jumpers as shipped from the
factory for stand-alone operation of hot water supply boilers.
Figure 5-5 shows connections to the terminal strip for
Remote ON/OFF control of the hot water supply boiler. The
1C-1NO jumper must be removed when making these wiring
connections. This remote ON/OFF control will provide an
Enable/Disable signal to the unit and allow the unit to operate
based on the stage setpoints, until the remote ON/OFF signal
is cancelled.
UNIT
PUMP
GROUND
SPLICE
L
N
120V
SUPPLY
LBL20174 REV A
CHASSIS
GROUND
UNIT
PUMP
1 HP MAX
IMG00594
Figure 5-2_Line Voltage Field Wiring Connections
Low voltage connections
1. Route all low voltage wires through the knockouts on the
left side of the heater, as shown in FIG. 5-3.
2. Connect low voltage wiring to the low voltage connection
board, reference the connection diagram on pages 66 and
67 of this manual.
Figure 5-6 shows the connections necessary to operate the unit
as a two-stage (High/Low Fire) hot water supply boiler from
an Energy Management System (EMS). For use with EMS, the
controller should be set to Mode 3 and the Boil Max adjusted
to the desired seeting to allow the controller to act as an upper
limit while the EMS controls the actual setpoint temperature.
Figure 5-7 shows the Continuous and Intermittent terminals.
External safety devices connected to these terminals will function
to protect the unit. Devices connected to the Intermittent
terminals (B1 and B2) are monitored only when there is an
active Call for Heat. Devices connected to the Continuous
terminals (A1 and A2) are monitored continuously and will
activate an alarm (if the unit is equipped with the alarm option)
anytime the safety device senses an abnormal condition.
Figure 5-8 shows the wiring of a tank sensor. A tank sensor
must be wired to the low voltage terminal strip in order for the
pump delay to function properly.
LOW VOLTAGE
KNOCKOUTS
LINE VOLTAGE
KNOCKOUTS
IMG00595
Figure 5-3_Routing Field Wiring
39
Installation & Service Manual
5
Electrical connections
Figure 5-4_Stand-alone operation
1
2
+
3
4
5
6
7
8
9
10
+
Figure 5-8_Remote sensor for pump delay
TANK
SENSOR
+
6
B2 INTERMITTENT
B1 LIMITS
A2 CONTINUOUS
A1 LIMITS
2 NO HIGH FIRE
2 C ENABLE
1 NO LOW FIRE
1 C ENABLE
+
+
+
+
+
+
+
CONNECTION BOARD
FIELD SUPPLIED
WIRING
7
8
9
10
1
2
TANK
SENSOR
3
4
REQUIRED IN ORDER
FOR PUMP DELAY TO
FUNCTION PROPERLY
5
1
2
+
3
4
5
6
7
8
9
10
+
+
+
+
+
+
+
+
+
TANK
SENSOR
B2 INTERMITTENT
B1 LIMITS
A2 CONTINUOUS
A1 LIMITS
2 NO HIGH FIRE
2 C ENABLE
1 NO LOW FIRE
1 C ENABLE
6
1
7
2
8
3
9
4
10
5
Remote mounting of a sensor
Figure 5-5_Remote on/off hot water supply boiler
Remote
on/off
1
2
+
3
4
5
6
7
8
9
10
+
+
TANK
SENSOR
+
B2 INTERMITTENT
B1 LIMITS
A2 CONTINUOUS
A1 LIMITS
2 NO HIGH FIRE
2 C ENABLE
1 NO LOW FIRE
1 C ENABLE
+
+
+
+
+
+
6
1
7
2
8
3
9
4
10
5
Figure 5-6_Two-stage (high/low fire) hot water supply
boiler
1
2
Stage 2
Stage 1
TANK
SENSOR
+
+
3
4
5
6
7
8
9
10
B2 INTERMITTENT
B1 LIMITS
A2 CONTINUOUS
A1 LIMITS
2 NO HIGH FIRE
2 C ENABLE
1 NO LOW FIRE
1 C ENABLE
+
+
+
+
+
+
+
+
6
1
7
2
8
3
9
4
10
5
To mount remote sensor, follow the guidelines below. Take
care to correctly wire sensors to the unit. Erratic temperature
readings can be caused by poor wiring practices. Twist
the wires between the unit and the remote sensor. Turn
wires at least three or four turns per linear foot of wiring.
This provides common mode rejection of some types of
electrical interferences.
1.
Do not route temperature sensor wiring with building
power wiring.
2.
Do not locate temperature sensor wiring next to control
contactors.
3.
Do not locate temperature sensor wiring near electric
motors.
4.
Do not locate temperature sensor wiring near welding
equipment.
5.
Make sure good mechanical connections are made to the
sensor, any interconnecting wiring and the controller.
6.
Do not mount sensor with leadwire end pointing up in an
area where condensation can occur.
7.
Use shielded wiring to connect the sensor to the control
when the possibility of an electrically noisy environment
exists. Shielded cable is recommended on all cable runs
of more than 25 feet in length.
Ground the cable shield at the
connection to the hot water supply
boiler temperature control only. Do
not ground the shielded cable at the
sensor end.
NOTICE
Figure 5-7_Field installation safety devices
Intermittent
Alarms
Continuous
Alarms
40
1
2
+
3
4
5
6
7
8
9
10
+
+
+
+
+
+
+
+
+
To maintain temperature accuracy,
sensor wires should be at least 18
AWG, see Table 5B.
TANK
SENSOR
B2 INTERMITTENT
B1 LIMITS
A2 CONTINUOUS
A1 LIMITS
2 NO HIGH FIRE
2 C ENABLE
1 NO LOW FIRE
1 C ENABLE
6
1
7
2
TABLE 5B
Remote Wire Connection
8
3
9
4
10
5
Wire Gauge
Max. Allowable Length
12 GA
14 GA
16 GA
18 GA
100 FT
75 FT
50 FT
30 FT
Installation & Service Manual
6
Start-up
Filling hot water supply boiler
Check vent and air piping
1. Close the system’s drain valve by turning the handle
clockwise.
2. Open a nearby hot water faucet to permit the air to
escape.
3. Fully open the cold water inlet pipe valve allowing the hot
water supply boiler and piping to be filled.
4. Close the hot water faucet as water starts to flow.
5. The hot water supply boiler is ready to be operated.
Inspect vent piping and air piping for signs of deterioration
from corrosion, physical damage or sagging. Verify air piping
and vent piping are intact and correctly installed per this
manual.
Check for gas leaks
 WARNING
Before starting the unit, and during initial
operation, smell near the floor and around
the unit for gas odorant or any unusual odor.
Remove the front access panel and smell
the interior of the hot water supply boiler
enclosure. Do not proceed with startup if
there is any indication of a gas leak. Use an
approved leak detection solution. Repair any
leaks at once.
 WARNING
Propane hot water supply boilers only –
Your propane supplier mixes an odorant
with the propane to make its presence
detectable. In some instances, the odorant
can fade, and the gas may no longer have
an odor. Before startup (and periodically
thereafter), have the propane supplier verify
the correct odorant level in the gas.
Check thermostat circuit(s)
1. Disconnect the two external wires connected to the enable
terminals on the connection board.
2. Connect a voltmeter across these two incoming wires.
Close each thermostat and relay in the external circuit
one at a time and check the voltmeter reading across the
incoming wires.
3. There should NEVER be a voltage reading.
4. If a voltage does occur under any condition, check and
correct the external wiring.
5. Once the external thermostat circuit wiring is checked and
corrected if necessary, reconnect the external thermostat
circuit wires to the connection board. Allow the unit to
cycle.
Placing the unit in operation
Hot water supply boiler operational checks
1. Turn the hot water supply boiler main power switch to the
“ON” position.
2. Verify operation of the electronic controller.
3. Program the electronic controller to desired settings.
4. Push the reset for the low water cutoff (if equipped).
5. Ensure that maximum flow to the unit does not exceed
55 GPM on Models 400 - 750 and 90 GPM on Models
1000 - 2100. Verify by checking temperature rise while
burner is firing at 100% of rated input.
6. Install a manometer on the gas supply to the hot water
supply boiler and verify minimum gas supply pressure as
the burner fires at 100% of rated input.
7. Verify operation of safeties as necessary (low water
cutoff, high limit, gas pressure, etc.,).
8. Verify that all adjustable points in the electronic controller
are set as required.
9. Once the unit analysis is complete, test the safety shutoff
device by turning the manual shutoff valve to the OFF
position and ensuring that the unit shuts down and
registers an alarm. Open the manual shutoff valve and reset
the control.
10. Place the hot water supply boiler back into normal
operation.
Hot water supply boiler operation
11. Hot water supply boiler should begin the start-up process
for the sequence of operation.
12. The unit will ignite at the proper ignition speed and
will stage to meet the system demand.
13. Ensure that inlet water temperature does not fall below
the specified minimum for the unit.
14. Based on tank demand, hot water supply boilers may run
for an extended period of time at a reduced rate of input to
maximize efficiency.
15. As tank demand is satisfied, the burner will cycle off
and the combustion air blower will run for a post
purge operation before the unit shuts down.
41
Installation & Service Manual
6
Start-up
Start the hot water supply boiler
Read and follow the Lighting Instructions in FIG. 6-1, on page
43.
If hot water supply boiler does not start
correctly
1. Check for loose connections or service switch off?
2. Is external limit control (if used) open? Is water temperature
above 200°F (93.3°C)?
3. Is thermostat set below tank temperature?
4. Is gas turned on at meter or unit?
5. Is incoming gas pressure less than 4.5" water column?
If none of the above corrects the problem, refer to the
Troubleshooting Section of the Genesis Service Manual.
 WARNING The venting system must be installed so that
it will prevent flue gas spillage and carbon
monoxide emissions, which will result in
severe personal injury or death.
Set hot water supply boiler temperature
To activate the Adjust Menu:
1. Press in and hold all three (3) programming buttons (Select,
+, and -) for three (3) seconds. The LCD screen will change
from the “View” Menu to the “Adjust” Menu.
2. Press the SELECT key until Target 1 appears, then use the +
and - keys to adjust the target to the desired setting.
3. Press the SELECT key to advance to Diff 1 and then use the
+ and - keys to adjust to the desired setting.
4. Repeat Steps 1 thru 3 above to set Target 2 and Diff 2.
42
Installation & Service Manual
6
Start-up
(continued)
Figure 6-1_Lighting Instructions
FOR YOUR SAFETY READ BEFORE OPERATING
WARNING: If you do not follow these instructions
exactly, a fire or explosion may result causing
property damage, personal injury or loss of life.
A. This appliance is equipped with an ignition
device which automatically lights the burner.
Do not try to light the burner by hand.
B. BEFORE OPERATING smell all around the
appliance area for gas. Be sure to smell next
to the floor because some gas is heavier
than air and will settle on the floor.
FOR YOUR SAFETY
"WHAT TO DO IF YOU SMELL GAS"
Do not try to light any appliance.
Do not touch any electrical switch; do not use
any phone in your building.
Immediately call your gas supplier from a
neighbor's phone. Follow the gas supplier's
instructions.
If you cannot reach your gas supplier,
call the fire department.
C. Use only your hand to turn the gas
control knob. Never use tools. If the
knob will not turn by hand, don't try to
repair it, call a qualified service technician. Force or attempted repair may
result in a fire or explosion.
D. Do not use this appliance if any part
has been under water. Immediately call
a qualified service technician to inspect
the appliance and to replace any part
of the control system and any gas control which has been under water.
OPERATING INSTRUCTIONS
1. STOP! Read the safety information above on
this label.
5. Push in gas control knob slightly and
turn clockwise
to "OFF."
OFF
2. Turn off all electric power to the appliance.
3. Open control access panel.
4. This appliance is equipped with an ignition
device which automatically lights the burner.
Do not try to light the burner by hand.
ON
NOTE: On the 36C valve, knob cannot be
turned to "OFF" unless knob is pushed in
slightly. Do not force.
6. Wait five (5) minutes to clear out any gas.
Then smell for gas, including near the floor. If
you smell gas, STOP! Follow "B" in the safety
information above on this label. If you don't
smell gas, go to the next step".
PSI
7. Turn gas control knob counterclockwise
to "ON."
OFF
IN
ON
OFF
GAS CONTROL KNOB
SHOWN IN THE "ON" POSITION
ON
8. Replace control access panel.
9. Turn on all electric power to the appliance.
10. If the appliance will not operate, follow
the instructions "To Turn Off Gas To
Appliance" and call your service technician or gas supplier.
TO TURN OFF GAS TO APPLIANCE
1. Turn off all electric power to the appliance
if service is to be performed.
3. Push in gas control knob slightly and
turn clockwise
to "OFF". Do not
force.
2. Open control access panel.
4. Replace control access panel.
OFF
ON
LBL2084 REV D
43
Installation & Service Manual
7
Operating information
General
Freeze protection
How the appliance operates
The Genesis uses a copper finned tube heat exchanger to
transfer heat from the flue products to the water. An electronic
controller initiates a call for heat and an ignition module
monitor controls blower and gas valve operation. The blower
provides both primary and secondary air to the burner and
forces the flue products out of the combustion chamber and
into the vent system. On models equipped with two speed
blowers, the controls change blower speed and firing stages,
based upon the heat demand. Gas valves regulate the amount
of gas supplied for the firing stages, which is mixed with the
combustion air supplied to the burner.
NOTICE
NOTICE
If an inline high gas pressure regulator is
used, it MUST BE of the lockup type and
be located a minimum of 10 feet from the
appliance. Failure to do so may result
in insufficient gas volume supplied to the
appliance.
If a pressure drop of more than 2" water
column occurs between Standby (static)
Mode and Operating (dynamic) Mode, a
gas volume problem exists. Contact the gas
utility, gas supplier, qualified installer, or
service agency to determine the necessary
steps to provide the proper gas volume to
the appliance.
How the control module operates
The electronic controller and ignition module receive inputs
from appliance sensors and external devices. The electronic
controller controls pump operation and regulates heat input
by activating the ignition module which controls the blower
and gas valve. The user programs the controller to meet system
needs by adjusting control parameters. These parameters set
operating temperatures and appliance operating modes. Hot
water supply boiler operation can be based on a tank sensor or
an external sequencer device.
Protection features
Max Delta T – (factory default is off)
A maximum T feature is provided. If enabled, this will allow
the controller to monitor the hot water supply boiler’s T to
allow it to display a Max T error and enable the alarm circuit
should the programmed value be exceeded. The maximum T
can be set to a value from 80°F to 20°F or OFF. If set to OFF it
will disable this feature. This can be useful to alert the user to
either poor flow or hard water issues. Factory default is OFF.
.
44
The controller monitors the inlet and outlet sensor. If either
sensor drops below 45°F (7.2°C), the pump will turn on to
circulate water through the heat exchanger.
 CAUTION
This feature does not eliminate the
possibility of freezing. The installer must
still use recognized design, installation and
maintenance practices to prevent freeze
potential of the appliance and system.
High limit operation – manual reset
When outlet temperature exceeds either 200°F or 210°F allowed
by local codes, a the high limit will trip. The appliance will shut
down until water cools down and the RESET button on the high
limit is pressed.
Monitor external limits
Connections are provided on the connection board for external
limits. The unit will shutdown and operation will be inhibited
whenever any of these limits open. Louver proving switch is one
example.
Optional Run-time and alarm outputs
If ordered, dry contacts for indicating appliance is running or
fault conditions exist with either the electronic controller or
ignition module that either require attention or are inhibiting
operation of the unit.
Installation & Service Manual
7
Operating information
(continued)
User interface
The electronic controller has a Liquid Crystal Display (LCD) to supply information. The LCD allows for setup and monitoring
of the unit. Three (3) buttons (“Select”, “+” & “-“) are provided for selecting and adjusting settings.
Figure 7-1_User Interface Screen
Menus
Adjust
All of the items displayed by the electronic controller are
organized into two (2) menus. These menus are listed on
the upper right-hand side of the display (Menu Field). The
default menu for the controller is the View Menu. While in
the View Menu, the VIEW segment is displayed. To select
the Adjust Menu, press and hold all three (3) buttons for 3
seconds simultaneously. The display then advances to the
Adjust Menu and the ADJUST segment is turned on in the
display. The display will automatically revert back to the
View Menu after 20 seconds of keypad inactivity. Once in
a menu, there will be a group of items that can be viewed
within that menu.
To make an adjustment to a setting in the control, begin by
selecting the Adjust Menu by pressing and holding all three (3)
buttons simultaneously and then select the desired item using
the SELECT button. Finally, use the + or - button to make the
adjustment.
Return water temperatures must not be
 WARNING less than 140°F.
Figure 7-2_Symbol Descriptions
Select
The abbreviated name of the selected item will be displayed
in the item field of the display. To view the next available
item, press and release the SELECT button. Once you have
reached the last available item in a menu, pressing and
releasing the Select button will return the display to the first
item in the selected menu.
45
Installation & Service Manual
7
Operating information
Powering up the control
When the unit is turned on, the controller will power up and turn on all segments in the display for two (2) seconds. The software
version is then displayed for two (2) seconds before the controller enters into the Normal Operating Mode.
Figure 7-3_Powering Up the Controller
Modes of operation (Mode)
Mode 3 – External Sequencer Operation
The controller allows for two (2) modes of operation. Mode 2
for standalone operation and Mode 3 for external sequenced
operation. The mode of operation is selected using the MODE
item in the Adjust menu.
This mode allows for the use of an external Building
Management System (BMS) or sequencer to be used to control
water temperature. The mode of operation is selected using the
MODE item in the Adjust Menu.
Mode 2 – Standalone Operation
Figure 7-5_External Sequencer
This is the default mode that allows the electronic controller to
stage the unit ON and OFF to control water temperature.
Figure 7-4_Standalone Operation
46
Installation & Service Manual
7
Operating information
(continued)
View menus
Error and warnings
Depending on the Mode and Access Level selected (User or Advanced),
the following items may be view while the electronic controller is
powered up:
Depending upon the Mode and parameter settings the
following error and/or warning messages may appear in
the electronic controller display when a fault condition
is sensed by the controller.
Errors
Error and warning messages.
BOIL OUT
Outlet water temperature.
BOIL IN
Inlet water temperature.
BOIL T
Difference between sensed values of the outlet and inlet temperature
sensors.
TANK
Tank water temperature.
BOIL ON
Accumulated run time of hot water supply boiler up to 999 hours, then
resets and repeats.
ADJUSTment menus
Depending on the Mode and Access Level (User or Advanced), several
adjustable parameter settings are provided to control the operation of
the unit.
MODE
Select 2 for standalone hot water supply boiler operation or 3 for
an externally sequenced (or controlled by an external Building
Management System) hot water supply boiler operation. Selection is
either 2 or 3.
BOIL MAX (Advanced dipswitch position)
Maximum hot water supply boiler target temperature. Selection is
from 70° to 190°F. Factory default is 190°F.
Setpoint TARGET 1
Stage 1 setpoint target temperature. Selection is from 70°F to Boil Max.
Factory default is 125°F.
DIFF 1
Stage 1 differential. Selection is from 2° to 42°F. Factory default is 2°F.
Setpoint TARGET 2
Stage 2 setpoint target temperature. Selection is from 70°F to Boil Max.
Factory default is 123°F.
DIFF 2
Stage 2 differential. Selection is from 2° to 42°F. Factory default is 2°F.
STG DLY (Advanced dipswitch position)
Delay between stages. Selection is from 0:00 to 5:00 minutes in 10
second increments. Factory default is 30 seconds.
T MIN (Advanced dipswitch position)
Determines when the pump will stop purging heat from the heat
exchanger. Selection is from ON (for continuous pump mode), 1 to
20°F or OFF (when set to OFF, pump will run for 30 seconds after unit
shuts off). Factory default is 5°F.
T MAX (Advanced dipswitch position)
Determines when to generate a delta T MAX error code. Selection is
from 20°F to 80°F or OFF (to disable delta T max function). Factory
default is OFF.
Units
Allows for selection between Fahrenheit and Celsius. Selection is
either C° or F°. Factory default is °F.
E01 “Err”
Electronic controller’s EEPROM read an error during
power up.
E02 “Err”
Freeze protection is in progress, pump may be running
to prevent damage to the appliance.
BOIL OUT “SHr”
Hot water supply boiler outlet sensor may be shorted.
BOIL OUT “OPn”
Hot water supply boiler outlet sensor may be open.
BOIL IN “SHr”
Hot water supply boiler inlet sensor may be shorted.
BOIL IN “OPn”
Hot water supply boiler inlet sensor may be open.
TANK “SHr”
Tank sensor may be shorted.
TANK “OPn”
Tank heater inlet sensor may be open.
T MAX
If set, the maximum delta T was exceeded.
47
Installation & Service Manual
7
Operating information
Figure 7-7_View Menu - Mode 3
Figure 7-6_View Menu - Mode 2
REVIEW
SETTINGS
Access by
Access by
Review Settings
View Menus
Access by
(Pressing &
Holding “ S elec t” ,
“ +” and “ -“ buttons
for 3 seconds)
Adjust Menus
(Pressing &
Holding Select)
(Pressing Select)
Mode 2
Outlet Temp
Mode 2
OUT
BOIL
2
120
MODE
F
200
BOIL
IN
BOIL
120
F
135
TARGET
I
5
T
200
MAX
F
BOIL
135
TARGET
132
I
TANK
DIFF
F
135
TARGET
2
ON
BOIL
I
F
023
135
TARGET
F
F
2
Delay for Stage 2 (*)
2:00
min
DLY
STG
min
DLY
STG
Min. DeltaT Pump Off (*
ADJUST
05
OFF
MIN
T
Max. DeltaT Alarm
Max. DeltaT Alarm (*)
ADJUST
MAX
42
MAX
T
OFF
T
°F or °C
°F or °C
ADJUST
F
48
Max. DeltaT Alarm (*)
ADJUST
F
F
I2
Boil OnTime (*)
2
ADJUST
4
2
OFF
MIN
MAX
OFF
T
TANK
°F or °C
VIEW
BOIL
DIFF
T
5
127
ADJUST
MIN
F
ADJUST
F
VIEW
Dem
F
Min. DeltaT Pump Off
200
Min. DeltaT Pump Off (*)
Tank Temperature
I
ADJUST
DIFF
2:00
MAX
T
Target 2 Diff
Delay for Stages 2
BOIL
I2
T
Target 2 Setpoint
Target 2 Diff
4
127
ADJUST
2
ADJUST
BOIL
ADJUST
F
VIEW
Dem
Hours Running
F
Boil Max. (*)
Boil Delta
F
Target 1 Diff
ADJUST
F
Target 2 Setpoint
IN
Dem
DIFF
3
I2
VIEW
ADJUST
F
Tank Temp
Target 1 Diff
2
142
Boil Inlet
ADJUST
BOIL
ADJUST
BOIL
ADJUST
F
Target 1 Setpoint
Delta Temp
F
OUT
MODE
Dem
Target 1 Setpoint
Mode 3
Boil Inlet
Boil Max (*)
Inlet Temp
F
View Menus
MODE
ADJUST
MAX
(Pressing Select)
Access by
(Pressing &
Holding “ S elec t” ,
“ +” and “ -“ buttons
for 3 seconds)
Adjust Menus
VIEW
2
Dem
Boil Max
Access by
ADJUST
ADJUST
BOIL
EXTERNAL SEQUENCER MODE 3
STANDALONE HOT WATER SUPPLY BOILER MODE 2
ON
238
ADJUST
F
I2
Dem
Installation & Service Manual
7
Operating information
(continued)
Access menus
TABLE - 7A
ACCESSING MENUS
VIEW MENUS
ADJUST MENUS
Press and release SELECT button to
advance View Menus.
Press all three (3) buttons (Select, +
and -) for three (3) seconds to enter
Adjustment Menus.
Figure 7-8_Error Messages
SENSOR FAILURE/ERRORS
Outlet Sensor Open
BOIL
OUT
Inlet Sensor Open
BOIL
OPn
Outlet Sensor Shorted
IN
OUT
SHr
OPn
MAX
Err
T
Inlet Sensor Shorted
VIEW
BOIL
TEMPERATURE RISE SETTING EXCEEDED
FREEZE PROTECTION
VIEW
F
BOIL
I2
IN
SHr
Dem
Tank Sensor Open
F
I2
E02
Dem
Tank Sensor Shorted
EEPROM POSSIBLY CORRUPT
VIEW
OPn
TANK
SHr
TANK
F
I2
E01
Dem
49
Installation & Service Manual
7
Operating information
Figure 7-9_LED Diagnostic Codes
Status LED Diagnostic Codes
Code
Sequence
Condition
Status LED Diagnostic Codes
Code
Sequence
Condition Lights
Constant
ON
System OK, no faults present.
Prepurge
Operation for combustion air fan
before ignition on stages 1 and 2.
Constant
OFF
Possible control fault, check power; LED
may be defective, do not replace control if
all operational sequences function properly,
see Troubleshooting Guide.
Trial for
Ignition
Hot surface igniter preparing to
light burners.
Stage 1
ON
Burners for stage 1 operating.
One
Flash
Low Air, check air pressure switch and hoses
to pressure sensing points, fan, venting and
sealing of pressurized chamber. Note: Brief
flashing normal on fan start-up proving.
Stage 2
ON
Burners for stage 2 operating.
Two
Flashes
Flame without call for heat, check for a gas
valve stuck in the open position, air, venting,
burners and the combustion process. Fan
will remain on.
Status
Remote status light for ignition
module.
Alarm
Indicates flame failure on the
ignition module and will indicate
additional alarms if the alarm of any
failure option is purchased.
Three
Flashes
Lockout due to flame failure, push the
reset button on the diagnostic panel after
correcting ignition problem. Initial heater
start up without properly bleeding air from
the gas line may require multiple reset
functions to achieve proper ignition.
Four
Flashes
Igniter failure, igniter will not maintain a
minimum 2.75 amp current draw, caused
by low voltage, bad wiring/continuity, high
resistance or igniter failure.
Five
Flashes
Power supply problem, check for low supply
voltage or transformer output less than 18
VAC.
Six
Flashes
Replace ignition module, internal fault.
50
Installation & Service Manual
7
Operating information
(continued)
Hot surface ignition system
Hot Surface Igniter and Ignition Control Module The 399,999
- 750,000 Btu/hr models have one ignition module and one hot
surface igniter. The 990,000 - 2,070,000 Btu/hr models have two
ignition modules and two hot surface igniters.
Figure 7-10_Hot Surface Igniter
Figure 7-11_Hot Surface Ignition Control Module
A soft-lockout condition will operate the combustion air fans
for the post purge cycle and then the ignition module will
pause for approximately five minutes. At the end of this timed
pause, the ignition module will attempt a new trial for ignition
sequence. If the soft-lockout fault condition has subsided or
has been corrected at the end of the timed pause, main burner
ignition should be achieved with the resumption of the normal
trial for ignition sequence. If the control sensed fault is not
corrected, the ignition module will continue in the soft-lockout
condition. If the electronic thermostat opens during the softlockout period, the ignition module will exit soft lockout and
wait for a new call for heat from the thermostat. A soft-lockout
condition may also be reset by manually cycling the thermostat
or turning the main power switch “OFF” and then “ON” after
the control sensed fault has been corrected.
Diagnostic status indication
The ignition module has an LED which indicates the status of the
safety circuits. A remote Ignition Module Status indicating light
is wired from the ignition module Status LED and mounted on
the front diagnostic panel. The flashing operation of this light
indicates the diagnostic status of the ignition control module.
The status LED, mounted on the ignition module flashes a code
sequence from the Ignition Module to indicate the status of the
ignition process. See FIG. 7-9 for the flashing diagnostic status
codes as signaled by the ignition module.
Hot surface ignition control module
Ignition module lockout functions
The ignition module may lockout in either a hard-lockout
condition, requiring pushing of the RESET button to recycle
the control, or a soft-lockout condition which may recycle after
an approximate five-minute waiting period. This soft-lockout
condition is intended to allow self-correcting faults to correct
themselves and permit normal operation. A typical hardlockout fault is a flame failure condition. An ignition module
that is in a hard-lockout condition may only be reset by pushing
the RESET button next to the ignition control or the “RESET”
button on the diagnostic panel on the left end of the unit. Upon
a flame failure, the RESET button is only active after the control
module has completed its post-purge cycle. Turning main power
“OFF” and then “ON” or cycling the thermostat will not reset
a hard-lockout condition. Wait five seconds after turning on
main power before pushing the RESET button when the ignition
module is in a hard lockout. The ignition module will go into
a soft lockout if conditions of low air, low voltage or low hot
surface igniter current are present.
51
Installation & Service Manual
8
Domestic water heater application
This section contains specific instructions for those appliances
used to supply domestic hot water. All warnings, cautions,
notes and instructions in the general installation and operation
sections apply to these instructions. Hot water supply boilers
are designed for installation with a storage tank.
A circulating pump MUST be installed in the piping assembly
to the storage tank and valves used to control water velocity
through the appliance. Proper water velocity is important for
correct operation of your hot water supply boiler. The operation
of the circulating pump, proper sizing of the piping between the
tank and heater and the control of water velocity, as explained
in this section, are important for correct operation of your hot
water supply boiler.
To ensure proper velocity through the heat
NOTICE
exchanger, it is necessary to regulate the
temperature rise across the heat exchanger
from inlet to outlet. This must be done
on initial installation and periodically
rechecked. With the correct temperature
rise across the heat exchanger when the hot
water supply boiler is firing at 100% of rated
input, you may be assured of the proper
velocity in the tubes. This will yield long life
and economical operation from your hot
water supply boiler.
Excessive lime/scale build-up in the heat
exchanger tubes is a result of restricted flow
and too little velocity in the tubes. Excessive
pitting or erosion in the tube is caused by
high water flow and too much velocity
through the tubes. Care should be taken
to measure temperature rise and maintain
velocity as follows:
Initial set-up of maximum water flow
On initial start-up of the Genesis the maximum water flow
through the heat exchanger must be manually set before normal
operation begins.
TABLE - 8A
MAXIMUM WATER FLOW
 CAUTION: The maximum flow rate through a Genesis hot
water supply boiler with a copper heat exchanger must be set to
provide and not exceed the following flow:
Model
Maximum Flow
52
400 - 750
55 GPM
1000 - 2100
90 GPM
If higher flow rates are required through the hot water supply
boiler, an optional Cupro Nickel heat exchanger is available.
Consult the factory for specific application requirements.
The heat exchanger is capable of operating within the design
flow rates required for the hot water supply boiler, storage
tank(s), and connecting piping. Erosion of the finned copper
tubes may occur if the flow rate exceeds the maximum allowable
flow rate through the hot water supply boiler. The maximum
flow rate through the hot water supply boiler must be adjusted.
Maximum flow on Models 400 - 750 is 55 GPM and 90 GPM on
Models 1000 - 2100. Flow rate can be determined by measuring
the temperature rise through the hot water supply boiler when
it is firing at full rate input.
TABLE - 8B
TEMPERATURE RISE AT FULL RATE FIRE
55 AND 90 GPM FLOW
Model
400
500
650
750
1000
Temperature Rise
12°F (6.7°C)
15°F (8.3°C)
20°F (11.1°C)
23°F (12.8°C)
19°F (10.6°C)
1250
24°F (13.3°C)
1450
27°F (15°C)
1800
34°F (18.9°C)
2100
39°F (21.7°C)
1. The pump must run continuously when the burner is
firing.
2. With the pump running and the burner in the hot water
supply boiler in the off cycle, the inlet water temperature
and outlet water temperature readings on the Operator
Interface should read approximately the same temperatures.
Water Temperature Rise on the Operator Interface should
read near zero.
3. Turn the hot water supply boiler on and allow time for the
temperature to stabilize. Check the water temperature rise
in the Operator Interface when the burner is firing at 100%
of rated input.
4. Compare the water temperature rise in the Operator
Interface with the required temperature rise. Should
adjustment be needed, proceed as follows.
Installation & Service Manual
8
Domestic water heater application
If the temperature rise is too high, the water velocity is
too low, adjust as follows:
Water chemistry
NOTICE
1. Check for restrictions in the outlet of the hot water
supply boiler.
2. Be sure all valves are open between the hot water
supply boiler and the storage tank. Ensure that all ball
valves are fully ported.
3. Check the pump to be sure it is running properly and
that the pump motor is running in the proper
direction.
4. Check diameter and length of the piping between the
storage tank and hot water supply boiler against the
head capacity of the circulating pump.
5. Be sure the pipes between the hot water supply boiler
and storage tank are not less than 2 or 2 1/2 inch
(63.5mm) diameter (depending on model). To increase
flow and decrease temperature rise, increase the piping
to 3 inch (76.2mm) diameter (depending on model) to
decrease head loss in the piping to the storage tank.
(continued)
Water temperature rise and maximum flow
data is based on heating potable water with
a hardness of 5 to 25 grains per gallon and
total dissolved solids not exceeding 350
ppm.
The required temperature rise and the standard circulating
pump are sized based on the heating of potable water with
a hardness of 5 to 25 grains per gallon and a total dissolved
solids not exceeding 350 ppm. Consult the manufacturer when
heating potable water exceeding these specifications. Heating
of high hardness and/or high total dissolved solids water may
require a larger circulating pump, an optional Cupro Nickel
heat exchanger and a revised temperature rise specification
based on the water chemistry of the water to be heated. Water
with a hardness of less than 5 grains per gallon will usually
have a pH which can be aggressive and corrosive causing nonwarrantable damage to the heater, pump, and associated piping.
Corrosion due to water chemistry generally shows up first in
the hot water system because heated water increases the rate of
corrosive chemical reactions.
6. Common manifold piping for multiple unit
installations will require larger minimum pipe sizes
and tank circulating tappings to ensure proper flow.
If the temperature rise is too low, the water velocity is too
high, adjust as follows:
1. Temperature rise can be increased by slowly closing the
field-installed ball valve in the outlet piping from the
hot water supply boiler to the storage tank to achieve
the proper temperature rise.
2. Sustained high water velocity and low temperature rise
may result in pitting or erosion of the copper tubes in
the heat exchanger. This is a non-warrantable failure.
Temperature rise must be properly adjusted to achieve
the specified flow rate.
3. Once temperature rise has been properly set, return to
normal operation.
 CAUTION
Temperature rise cannot be adjusted
when the burner is firing at less than
100% of rated input.
53
Installation & Service Manual
Domestic water heater application
8
Figure 8-1_Typical Water Heater Application Piping with Storage Tank
NOTES:
55
Genesis Boiler
COMMON MANIFOLD SIZE (Min.)
Models: 400, 500, 650 & 750
Diameter
Number of Units
GPM
(in.)
2
1
Finished Floor
1. PREFERRED PIPING LAYOUT.
HOT WATER
TO FIXTURES
1
90
EXPANSION
TANK
COLD WATER
SUPPLY
SYSTEM RETURN
COMMON MANIFOLD SIZE (Min.)
Models: 1000, 1250, 1450, 1800 & 2100
Diameter
Number of Units
GPM
(in.)
2 1/2
ALTERNATE COLD WATER
CONNECTION FOR
“OLD-STYLE” TANK
2. THE TEMPERATURE AND PRESSURE RELIEF VALVE SETTING SHALL NOT EXCEED PRESSURE RATING OF ANY COMPONENT IN THE SYSTEM.
3. SERVICE VALVES ARE SHOWN FOR SERVICING HOT WATER SUPPLY BOILER. HOWEVER, LOCAL CODES SHALL GOVERN THEIR USAGE.
4. A. O. SMITH PIPING METHOD IS BASED ON 50 EQUIVALENT FEET OF PIPING. HOT WATER SUPPLY BOILER PLACEMENT SHALL BE
AS CLOSE AS PRACTICAL TO THE STORAGE TANK. APPLICATIONS IN EXCESS OF THESE RECOMMENDATIONS
SHALL REQUIRE A LICENSED ENGINEER FOR DESIGN ASSISTANCE.
54
Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
NOTICE
Installation & Service Manual
1
55
COMMON MANIFOLD SIZE (Min.)
Models: 400, 500, 650 & 750
Diameter
Number of Units
GPM
(in.)
2
Finished Floor
NOTES:
1. PREFERRED PIPING LAYOUT.
HOT WATER TO FIXTURES
AOS
STORAGE TANK
1
90
SYSTEM
RETURN
COMMON MANIFOLD SIZE (Min.)
Models: 1000, 1250, 1450, 1800 & 2100
Diameter
Number of Units
GPM
(in.)
2 1/2
ALTERNATE
LOCATION
COLD WATER
SUPPLY
EXPANSION
TANK
2. THE TEMPERATURE AND PRESSURE RELIEF VALVE SETTING SHALL NOT EXCEED PRESSURE RATING OF ANY COMPONENT IN THE SYSTEM.
3. SERVICE VALVES ARE SHOWN FOR SERVICING HOT WATER SUPPLY BOILER. HOWEVER, LOCAL CODES SHALL GOVERN THEIR USAGE.
4. A. O. SMITH PIPING METHOD IS BASED ON 50 EQUIVALENT FEET OF PIPING. HOT WATER SUPPLY BOILER PLACEMENT SHALL BE
AS CLOSE AS PRACTICAL TO THE STORAGE TANK. APPLICATIONS IN EXCESS OF THESE RECOMMENDATIONS
SHALL REQUIRE A LICENSED ENGINEER FOR DESIGN ASSISTANCE.
Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
NOTICE
(continued)
Domestic water heater application
8
Figure 8-2_Single Water Heater Application Piping with Two Storage Tanks
55
Installation & Service Manual
Domestic water heater application
8
Figure 8-3_Multiple Water Heater Application Piping with a Single Storage Tank
Finished Floor
NOTES:
4
3
2
330
275
220
165
110
6
6
5
5
4
3 1/2
8
7
6
5
4
3
2
720
630
540
450
360
270
180
7
7
6
6
6
5
COMMON MANIFOLD SIZE (Min.)
Models: 1000, 1250, 1450, 1800 & 2100
Diameter
Number of Units
GPM
(in.)
4
5
385
COMMON MANIFOLD SIZE (Min.)
Models: 400, 500, 650 & 750
Diameter
Number of Units
GPM
(in.)
3
6
440
EXPANSION
TANK
COLD WATER
SUPPLY
CIRCULATING
PUMP
SYSTEM
RETURN
7
HOT WATER
TO FIXTURES
ALTERNATE COLD WATER
CONNECTION FOR
“OLD-STYLE” TANK
8
1. PREFERRED PIPING LAYOUT.
2. THE TEMPERATURE AND PRESSURE RELIEF VALVE SETTING SHALL NOT EXCEED PRESSURE RATING OF ANY COMPONENT IN THE SYSTEM.
3. SERVICE VALVES ARE SHOWN FOR SERVICING HOT WATER SUPPLY BOILER. HOWEVER, LOCAL CODES SHALL GOVERN THEIR USAGE.
4. A. O. SMITH PIPING METHOD IS BASED ON 50 EQUIVALENT FEET OF PIPING. HOT WATER SUPPLY BOILER PLACEMENT SHALL BE
AS CLOSE AS PRACTICAL TO THE STORAGE TANK. APPLICATIONS IN EXCESS OF THESE RECOMMENDATIONS
SHALL REQUIRE A LICENSED ENGINEER FOR DESIGN ASSISTANCE.
5. TEMPERATURE CONTROL PROBE (QUAD THERMISTOR PROBE, P/N 9006905005) MUST BE INSTALLED ONTO THE TANK,
AND CONNECTED TO EACH HOT WATER SUPPLY BOILER.
56
Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
NOTICE
Installation & Service Manual
Finished Floor
NOTES:
SYSTEM
RETURN
COLD WATER
SUPPLY
COMMON MANIFOLD SIZE (Min.)
Models: 1000, 1250, 1450, 1800 & 2100
Diameter
Number of Units
GPM
(in.)
4
180
5
270
6
2
6
3
COMMON MANIFOLD SIZE (Min.)
Models: 400, 500, 650 & 750
Diameter
Number of Units
GPM
(in.)
3
360
6
3 1/2
450
110
540
165
5
2
6
3
5
4
5
220
275
4
330
4
5
7
6
7
6
630
385
720
ALTERNATE
LOCATION
8
AOS
STORAGE TANK
EXPANSION
TANK
6
7
440
HOT WATER TO FIXTURES
7
8
1. PREFERRED PIPING LAYOUT.
2. THE TEMPERATURE AND PRESSURE RELIEF VALVE SETTING SHALL NOT EXCEED PRESSURE RATING OF ANY COMPONENT IN THE SYSTEM.
3. SERVICE VALVES ARE SHOWN FOR SERVICING HOT WATER SUPPLY BOILER. HOWEVER, LOCAL CODES SHALL GOVERN THEIR USAGE.
4. A. O. SMITH PIPING METHOD IS BASED ON 50 EQUIVALENT FEET OF PIPING. HOT WATER SUPPLY BOILER PLACEMENT SHALL BE
AS CLOSE AS PRACTICAL TO THE STORAGE TANK. APPLICATIONS IN EXCESS OF THESE RECOMMENDATIONS
SHALL REQUIRE A LICENSED ENGINEER FOR DESIGN ASSISTANCE.
5. TEMPERATURE CONTROL PROBE (QUAD THERMISTOR PROBE, P/N 9006905005) MUST BE INSTALLED ONTO THE TANK,
AND CONNECTED TO EACH HOT WATER SUPPLY BOILER.
Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
NOTICE
(continued)
Domestic water heater application
8
Figure 8-4_Multiple Water Heater Application Piping with Multiple Storage Tanks
57
Installation & Service Manual
8
Domestic water heater application
TABLE 8C
COMMON WATER MANIFOLD SIZE FOR MULTIPLE
HOT WATER SUPPLY BOILER INSTALLATIONS
Pipe sizing chart provides minimum pipe size for common
manifold piping to ensure adequate flow.
Number of Hot Water
Supply Boilers
Common Manifold Size (Min.)
Models
400 - 750
1000 - 2100
1
2"
2 1/2"
2
3"
4"
3
3 1/2"
5"
4
4"
6"
5
5"
6"
6
5"
6"
7
8
6"
7"
6"
7"
The standard circulating pump on this hot water supply boiler
is sized based on installation of a single storage tank and heater
in close proximity. If the number of fittings and straight
pipe exceeds the specified maximum equivalent number of
straight feet for a specified diameter of pipe, non-warrantable
operational problems may be experienced.
400 - 750 Models
1/4 HP, 120 VAC, 5.8 Amps
1000 - 2100 Models
1/2 HP, 120 VAC, 7.4 Amps
The standard pump selection is based on the following pipe and
fittings from the hot water supply boiler to the storage tank:
6 - 90° elbows
2 - ball valves
2 - unions
1 - cold water tee
Not more than 45 feet of straight pipe.
For every elbow and tee in excess of those shown above,
DEDUCT 6.5 FEET from the maximum allowable straight pipe
in the heater to tank circulating loop.
NOTICE
Pump operation
1. The hot water supply boiler must have a properly sized
circulating pump. This pump is sized to circulate water
between the heater and the storage tank only.
2. The pump is sized to the heater input and water
chemistry specifications noted in the Water Chemistry
section on page 53.
3. The diameter and length of the piping installed between
the storage tank(s) and hot water supply boiler must be
properly sized based on the capacity of the circulating
pump.
4. The pump must run continuously when the water
heater is energized. This is the standard operating
system for a hot water supply boiler.
A pump delay control function with an all bronze pump is
installed as standard equipment on all hot water supply boiler
systems. The pump will operate only while there is a “Call
for Heat” and for a timed period after the water temperature
setpoint is satisfied to remove any residual heat from the
combustion chamber.
5. Lubricate pump to manufacturer’s recommendations.
Pump damage due to inadequate lubrication is
non-warrantable.
The tank sensor must be installed in the tapping provided in
the lower 25% of the storage tank to achieve proper operation.
As shipped from the factory, the tank sensor is in the literature
package shipped with the unit. Placing the sensor in the tapping
provided on the storage tank will improve temperature response
and prevent short cycles of operation.
58
NOTICE
The factory supplied pump allowas enough
feet of head to accommodate pressure drop
of the unit and up to approximately 45
equivalent feet of piping with some limited
reserve. If additional lengths of piping are
required, it may be necessary to upgrade the
factory pump. Please refer to the pressure
drop curves in Section 4 of this manual for
the respective model’s heat exchanger to
determine pump requirements.
The factory supplied pump will
accommodate pressure drop of the unit plus
up to approximately 45 equivalent feet of
piping with some limited amount of reserve
capacity. If additional lengths of piping are
required beyond 45 equivalent feet, it may
be necessary to either upsize the piping or
upgrade from the factory pump. Consult the
respective pressure drop charts in Section 4 of
this manual for respective units.
TABLE 8D
MINIMUM PUMP PERFORMANCE
Based on heating potable water with a hardness of 5 to 25
grains per gallon and total dissolved solids not exceeding
350 ppm. See Water Chemistry section on page 53.
Model
GPM Ft. Hd.
400 - 750
55
10
1000 - 2100
90
15
When installing multiple hot water supply boilers and/or
multiple storage tanks, the diameter of the inter-connecting pipe
and all fittings must be increased. An increase in pipe diameter
will decrease head loss in the system piping and ensure proper
flow. Proper pipe size between the heater and storage tank
MUST be maintained to ensure that the standard pump supplied
on the hot water supply boiler will maintain desired flow.
Installation & Service Manual
8
Domestic water heater application
Thermostat adjustment procedure
 CAUTION
1. Press all three (3) buttons (SELECT, +, -) simultaneously
and hold for three (3) seconds. The Adjust menu will
appear in the controller display.
2. Press and release the SELECT key to step through all
available settings.
3. Setpoint Targets 1 & 2 and DIFFs 1 & 2 need to be set
to the desired settings.
4. To access all settings, the Advanced/User dipswitch
should be set to the “Advanced” position.
5. Once setpoints are adjusted, the dipswitch may be set
back to the User position if desired.
6. After all adjustments have been made, allow 10 seconds
for the controller to revert back to its operating mode.
Note: The unit will not run while the controller is in Adjust
Mode.
Minimum water temperatures (domestic
hot water use)
(continued)
An appliance allowed to operate at return
temperatures below the specified minimum
setting may experience problems with
the operating controls, safety switches,
obstruction of the flue gas passages on the
heat exchanger, incomplete combustion,
and possible flue gas spillage. Sustained
operation at lower than specified water
temperatures may cause hazardous
conditions that may result in personal
injury or non-warrantable damage to the
appliance.
The maximum temperature setpoint that can be programmed
into the control module from the Operator Interface for water
heater operation is 190°F (88°C). The control is factory pre-set
at approximately 120°F (49°C). Facilities with small children or
invalids may require 120°F (49°C) or a lower temperature setting
to reduce risk of scald injury. Some states may require a lower
temperature setting. Check with your gas supplier for local
requirements governing the temperature setting. Remember,
no water heating system will provide exact temperature at all
times. Allow a few days of operation at this setting to determine
the correct temperature setting consistent with your needs.
Domestic water temperatures:
This high efficiency hot water supply boiler should be
operated at a temperature setting high enough to prevent
condensing of the products of combustion on the unit’s heat
exchanger or in the attached venting system. Use extreme
caution when storing water at elevated temperatures.
A water temperature setting maintained above the dew
point of the products of gas combustion should prevent
condensate formation and ensure proper performance
of the venting system. The manufacturer recommends
the use of a properly sized thermostatic mixing valve to
supply domestic hot water at temperatures less than 140°F
(60°C). Storing the water at a higher temperature and
thermostatically mixing the water will increase the available
quantity of mixed hot water, greatly reducing the possibility
of condensate formation on the heat exchanger or in the
venting system and help prevent the growth of water borne
bacteria.
NOTICE
NOTICE
1. This hot water supply boiler, when
set at the lower temperature setting, is not
capable of producing hot water of sufficient
temperature for sanitizing purposes.
2. Higher stored water temperature
increases the ability of the hot water supply
boiler to supply desired quantities of hot
water, however remember hotter water
increases the risk of scald injury.
Adequate care MUST be taken to
prevent a potential scald injury when
storing water at elevated temperatures
for domestic use.
Inlet water temperatures below the specified minimum
recommendations can excessively cool the products
of combustion resulting in condensation on the heat
exchanger. Condensation on the heat exchanger can cause
operational problems, bad combustion, sooting, flue gas
spillage and reduced service life of the related components.
Figure 8-5_Danger Warning
59
Installation & Service Manual
8
Domestic water heater application
Location of Cold Water Supply Piping Connections
Thermal expansion
Incorrect piping of the cold water supply to the system may result
in excessive low temperature operation causing condensate
formation on the primary heat exchanger and operational
problems. The cold water supply piping must be installed in
the discharge piping from the heater to the storage tank. This
allows the cold water to be tempered in the storage tank before
entering the heater. See typical installation drawings provided
in this manual for correct piping (FIG.’s 8-1 thru 8-4). Higher
water temperatures reduce the volume of condensate formed.
A relief valve that discharges periodically may be due to thermal
expansion in a closed system. A hot water supply boiler installed
in a closed system, such as one with a backflow preventer or
check valve installed in the cold water supply, shall be provided
with means to control expansion. Contact the water supplier or
local plumbing inspector on how to correct this situation. Never
plug or cap the relief valve discharge.
 CAUTION
Setting the temperature selector to higher
settings provides hotter water, which
increases the risk of scald injury.
 WARNING
Should overheating occur or the gas supply
fail to shut off, do not turn off or disconnect
the electrical supply to the pump. Instead,
shut off the gas supply at a location external
to the appliance.
Optional adjustable auxiliary high water
temperature limit control
ADJUSTABLE
AUXILIARY
HIGH WATER
TEMPERATURE
LIMIT CONTROL
(OPTION)
IMG00600
Figure 8-6_Adjustable Auxiliary High Water Temperature
Limit Control
A high limit control is located on the inside of the left front
panel, as shown in FIG. 8-6. The setting of this control knob
limits maximum discharge water temperature. The hot water
supply boiler temperature limit control is adjustable up to a
maximum setting of 210°F (99°C). This hot water supply boiler
also includes a fixed high water temperature limit control set to
200° (93.3°C).
NOTICE
60
The high limit control will not reset until the
water temperature has dropped below the
setpoint of the high limit.
Cathodic protection
Hydrogen gas can be produced in a hot water system that has
not been used for a long period of time (generally two weeks
or more). Hydrogen gas is extremely flammable. To prevent
the possibility of injury under these conditions, we recommend
the hot water faucet be open for several minutes at the kitchen
sink before you use any electrical appliance which is connected
to the hot water system. If hydrogen is present, there will be
an unusual sound such as air escaping through the pipe as the
hot water begins to flow. There should be no smoking or open
flames near the faucet at the time it is open.
Installation & Service Manual
9
Maintenance
Maintenance and annual startup
Table 9A_Service and Maintenance Schedules
Owner maintenance
Service technician
(see the following pages for instructions)
(see the Genesis User’s Information Manual for
instructions)
• Check appliance area
General:
• Address reported problems
• Inspect interior; clean and vacuum if
necessary;
Daily
• Check pressure/temperature
gauge
• Check for leaks (water, gas, flue,
condensate)
ANNUAL START-UP
• Examine venting system
• Check system water pressure/system
piping/expansion tank
• Check vent piping
• Check control settings
• Check air piping
• Check igniter
Monthly
• Check wiring and connections
• Check relief valve
• Replace combustion air filter
Note: More frequent replacement may
be necessary in dirty environments.
• Check flue gas passageways
• Flame inspection (stable, uniform)
• Inspect and clean the burner
• Check manifold gas pressure
Periodically
• Perform
start-up
checkout
and
performance verification per Section 6 in
the
Genesis
Installation
and
Operation Manual.
If combustion
indicate need:
or
• Test low water cutoff (if used)
• Reset button (low water cutoff)
performance
• Clean heat exchanger with a stiff bristle
brush
• Remove and clean burners
water. Dry before re-assembling.
using
Every
6 months
• Check appliance piping (gas and
water) for leaks
• Operate relief valve
• Clean the blower wheel with a brush and
vacuum. Do not let dirt from cleaning get
pulled into the blower.
61
Installation & Service Manual
9
Maintenance
 WARNING
Follow the service and maintenance procedures given throughout this manual and in component literature
shipped with the appliance. Failure to perform the service and maintenance could result in damage to the
appliance or system. Failure to follow the directions in this manual and component literature could result in
severe personal injury, death, or substantial property damage.
 WARNING
The appliance should be inspected annually only by a qualified service technician. In addition, the maintenance
and care of the appliance designated in Table 9A and explained on the following pages must be performed to
assure maximum appliance efficiency and reliability. Failure to service and maintain the appliance and system
could result in equipment failure.
 WARNING
Electrical shock hazard – Turn off power to the appliance before any service operation on the appliance except
as noted otherwise in this instruction manual. Failure to turn off electrical power could result in electrical
shock, causing severe personal injury or death.
Address reported problems
Check water system
1. Inspect any problems reported by the owner and correct
before proceeding.
1. Verify all system components are correctly installed and
operational.
Inspect appliance area
1. Verify that appliance area is free of any combustible
materials, gasoline and other flammable vapors and liquids.
Inspect appliance interior
1. Remove the outer access panels and inspect the interior of
the appliance.
2. Vacuum any sediment from inside the appliance and
components. Remove any obstructions.
Check all piping for leaks
 WARNING
Eliminate all system or appliance leaks.
Minerals can build up in sections, reducing
heat transfer, overheating heat exchanger,
and causing heat exchanger failure. Leaking
water may also cause severe property
damage.
1. Inspect all water and gas piping and verify to be leak free.
2. Look for signs of leaking lines and correct any problems
found.
3. Check gas line using the procedure found in Section 3 Gas Connections of the Genesis Installation and Operation
Manual.
Flue vent system and air piping
1. Check for gastight seal at every connection, seam of air
piping, and vent piping periodically inspected by a qualified
service agency.
 WARNING Venting system must be sealed gastight
to prevent flue gas spillage and carbon
monoxide emissions, which will result in
severe personal injury or death.
62
2. Check the cold fill pressure for the system. Verify it is
correct (must be a minimum of 12 PSI).
3. Watch the system pressure as the unit heats up (during
testing) to ensure pressure does not rise too high. Excessive
pressure rise indicates expansion tank sizing or performance
problem.
4. Inspect automatic air vents and air separators. Remove air
vent caps and briefly press push valve to flush vent. Replace
caps. Make sure vents do not leak. Replace any leaking
vents.
Check expansion tank
1. Expansion tanks provide space for water to move in and
out as the heating system water expands due to temperature
increase or contracts as the water cools. Tanks may be
open, closed, diaphragm or bladder type. See Section
4 - Water Connections of the Genesis Installation and
Operation Manual for suggested best location of expansion
tanks and air eliminators.
Installation & Service Manual
9
Maintenance
(continued)
Check relief valve
Inspect/replace hot surface igniter
1.
This unit uses a proven control module and a hot surface
igniter. The control module is not repairable. Any modification
or repairs will invalidate the warranty.
Inspect the relief valve and lift the lever to verify flow. Before
operating any relief valve, ensure that it is piped with its
discharge in a safe area to avoid severe scald potential. Read
Section 4 - Water Connections of the Genesis Installation
and Operation Manual before proceeding further.
 WARNING
Safety relief valves should be re-inspected
AT LEAST ONCE EVERY THREE YEARS,
by a licensed plumbing contractor or
authorized inspection agency, to ensure
that the product has not been affected by
corrosive water conditions and to ensure
that the valve and discharge line have not
been altered or tampered with illegally.
Certain naturally occurring conditions may
corrode the valve or its components over
time, rendering the valve inoperative. Such
conditions are not detectable unless the valve
and its components are physically removed
and inspected. This inspection must only
be conducted by a plumbing contractor or
authorized inspection agency – not by the
owner. Failure to re-inspect the hot water
supply boiler relief valve as directed could
result in unsafe pressure buildup, which can
result in severe personal injury, death, or
substantial property damage.
Following installation, the valve lever must
 WARNING
be operated AT LEAST ONCE A YEAR to
ensure that waterways are clear. Certain
naturally occurring mineral deposits may
adhere to the valve, rendering it inoperative.
When manually operating the lever, water
will discharge and precautions must be taken
to avoid contact with hot water and to avoid
water damage. Before operating lever, check
to see that a discharge line is connected to
this valve directing the flow of hot water
from the valve to a proper place of disposal.
Otherwise severe personal injury may result.
If no water flows, valve is inoperative. Shut
down the appliance until a new relief valve
has been installed.
2. After following the above warning directions, if the relief
valve weeps or will not seat properly, replace the relief valve.
Ensure that the reason for relief valve weeping is the valve
and not over-pressurization of the system due to expansion
tank waterlogging or undersizing.
 WARNING
Do not attempt to repair a faulty hot surface
igniter or control module. Any modification
or repairs may create hazardous conditions
that result in property damage, personal
injury, fire, explosion and/or toxic gases.
A faulty hot surface igniter or control module must be replaced
with an identical part. A specification igniter and control
module for this specific unit is available from your local
distributor. Do not use general purpose field replacement
control modules or igniters.
Ignition system checkout
1.
Turn off gas supply to unit.
2.
Turn electric power on.
3.
Adjust the setpoint targets on the temperature control to a
setting above water temperature or to the highest safe
setting.
4.
The igniter will cycle on trial for ignition.
5.
The ignition module will lock out and turn the alarm
light on.
6.
Adjust the Stage Differential and Boil Max to the desired |
settings.
7.
Turn on gas supply.
8.
Press the RESET button on the panel to reset the ignition
module.
9.
If ignition system fails to operate properly, repair work
must be performed by a qualified service person or
installer.
Check all wiring
Inspect all wiring, making sure wires are in good condition and
securely attached.
Check control settings
Press and hold the SELECT key, the controller will display the
current settings. When the Advanced/User switch is set to User,
only a limited group of settings will be shown. Changing the
dipswitch to the Advanced position will show all of the available
settings when the SELECT key is held down. In order to review
and adjust the settings, all three (3) keys (SELECT, +, -) must be
held down for three (3) seconds to enter the Adjust Mode. The
position of the Advanced/User dipswitch will also affect how
many items are allowed to be adjusted.
63
Installation & Service Manual
9
Maintenance
Perform start-up and checks
1.
Start appliance and perform checks and tests specified
in Section 6 - Start-up of the Genesis Installation and
Operation Manual.
2.
Verify cold fill pressure is correct and that operating
pressure does not go too high.
 CAUTION
When a Category IV vent system is
disconnected for any reason, the flue must
be reassembled and resealed according to the
vent manufacturer’s instructions.
Inspect and clean burner
1.
Turn off main power to unit.
2.
Turn off main manual gas shutoff to unit.
Visually check main burner flames at each start-up after long
shutdown periods or at least every six months. A burner
viewport is located on the burner mounting flange.
3.
Remove the front outer jacket panels.
4.
Disconnect manifold from gas train using union(s) just
below each gas valve(s).
 WARNING The area around the burner viewport is hot
and direct contact could result in burns.
5.
Remove mounting screws from manifold mounting
brackets. Pull the manifold/orifice assembly away from
burners. Repeat for each manifold assembly.
6.
Remove two mounting screws from burner and slide
burner out toward front of unit. Use caution to prevent
damage to burners, refractory, hot surface igniter or wiring.
7.
Remove soot from burners with a stiff bristle brush.
Check burner flame
Figure 9-1_Flame Pattern Illustration
NORMAL
YELLOW TIP
Dirt may be removed from burner ports by rinsing the
burner thoroughly with water. Drain and dry burners
before re-installing. Damaged burners must be replaced.
YELLOW FLAME
FLAME LIFT
Normal Flame: A normal flame at 100% of burner input is blue,
with slight yellow tips, a well defined flame and no flame lifting.
Yellow Tip: Yellow tipping can be caused by blockage or partial
obstruction of air flow to the burner.
Yellow Flames: Yellow flames can be caused by blockage of
primary air flow to the burner or excessive gas input. This
condition MUST be corrected immediately.
Lifting Flames: Lifting flames can be caused by over firing the
burner, excessive primary air or high draft.
If improper flame is observed, examine the venting system,
ensure proper gas supply and adequate supply of combustion
and ventilation air.
Check flue gas passageways
Any sign of soot around the inner jacket, outer jacket, flue
pipe connections, burner or in the areas between the fins on
the copper heat exchanger indicates a need for cleaning. The
following cleaning procedure must only be performed by a
qualified serviceman or installer. Proper service is required to
maintain safe operation. Properly installed and adjusted units
seldom need flue cleaning.
NOTICE
64
All gaskets/sealants on disassembled
components or jacket panels must be
replaced with new gaskets/sealants on
reassembly. Gasket and sealant kits are
available from your distributor.
When installed in a dusty and dirty location, the burners may
require cleaning on a 3 to 6 month schedule or as needed,
based on severity of contamination. Contaminants can be
drawn in with the combustion air. Non combustible particulate
matter such as dust, dirt, concrete dust or dry wall dust can
block burner ports and cause non-warrantable failure. The
standard inlet air filter will help eliminate dust and dirt from
entering the unit. Use extreme care when operating a unit for
temporary heat during new construction. The burners could
require a thorough cleaning before the unit is placed in service.
Access to the burners will require the following steps:
1.
2.
3.
4.
Turn off main electrical power to the appliance.
Turn off main manual gas shutoff to the appliance.
Remove the upper and lower outer front access doors.
Disconnect the manifold(s) from the gas train using the
union(s) just below each gas valve.
5. Disconnect the wiring to the hot surface igniter(s) and
ground.
6. Disconnect burner pressure line at burner.
7. Remove the screws from the manifold mounting bracket(s)
and remove the manifold(s).
8. Remove the screws from the burner mounting flanges and
slide the burner(s) out toward the front of the unit. Use
caution to prevent damage to the burners, refractory, hot
surface igniter, and wiring.
9. Remove soot from the burners with a stiff bristle brush.
Dirt may be removed from the burner ports by rinsing the
burner thoroughly with water. Drain and dry burners
before re-installing. Damaged burners must be replaced.
10. Reassemble in reverse order.
Installation & Service Manual
9
Maintenance
NOTICE
NOTICE
(continued)
When installed in a dusty and dirty location,
the burners may require cleaning on a 3 to 6
month schedule or as needed, based on the
severity of contamination. Contaminants
can be drawn in with the combustion air.
Non-combustible particulate matter such as
dust, dirt, concrete dust, or drywall dust
can block burner ports and cause nonwarrantable failure. The standard inlet air
filter will help eliminate dust and dirt from
entering the unit.
Figure 9-3_Adjusting air shutter - 1000 - 2100 Models
MORE AIR
LESS AIR
While burners are removed, check the heat
exchanger surface for sooting. If present, the
heat exchanger must be cleaned. Reference
the Heat Exchanger Cleaning procedures in
this manual.
Checking combustion air pressure
The combustion air fans are factory pre-set and should not
require adjustment in most cases. Follow the steps in the
Checking / Adjusting Combustion Air Pressure Section to adjust
the fan if a continuous Low Air status code occurs.
NOTICE
On the 400 - 750 models, the air shutter is
adjusted to the side of the fan as depicted in
FIG. 9-2. On the 1000 - 2100 models, the air
shutter is adjusted by sliding the arm located
on the front of the air box as depicted in
FIG. 9-3.
Check for proper installation and draft in the venting system
prior to any adjustments. Correct as needed.
AIR SHUTTER
ADJUSTING BRACKET
Adjusting combustion air pressure
The following is a recommended method for setting the
combustion air pressure. The following pressure settings are
for installations up to 4000 feet altitude. Contact the factory for
high altitude air pressure settings.
Upon removal of the upper front doors, locate the capped tee
in the pressure tubing that connects between the inner top and
the gas valves. Remove this cap and connect a hose from the
tee to a manometer.
For 400 - 750 models (reference FIG. 9-2)
1.
The combustion air chamber pressure for these models is
typically 1.2 - 1.3 inches water column when the fan is at
high speed.
2.
If adjustment is necessary, slightly loosen the nuts
connecting the fan to the inner top.
3.
Adjust the air shutter located underneath the fan assembly
to obtain the desired chamber pressure. Slide the shutter
inward to decrease the chamber pressure or outward to
increase the chamber pressure.
Figure 9-2_Adjusting air shutter - 400 - 750 Models
LESS AIR
For 1000 - 2100 models (reference FIG. 9-3)
MORE AIR
AIR SHUTTER
1.
The combustion air chamber pressure for these models is
typically 1.2 - 1.3 inches water column when the fan is at
high speed.
2.
If adjustment is necessary, slightly loosen the nut
located on the air shutter arm.
3.
Adjust the air shutter arm to obtain the desired chamber
pressure. Slide the arm inward to decrease the chamber
pressure or outward to increase the chamber pressure.
65
Installation & Service Manual
9
Maintenance
All models
4.
Once the adjustment procedure is complete, tighten all
connections, disconnect the manometer, and replace the
cap at the tee.
5.
Check all connections and test fire the unit.
6.
Replace all panels.
3.
Replace the cap and check the manifold
Note: Allow the unit to re-light if necessary.
4.
Repeat the steps above to match the manifold pressures
from Table 9B.
5.
Once the adjustment procedure is complete, turn off
the appliance, disconnect the manometer, replace and
tighten all connections, and replace all panels.
6.
Turn on the appliance and test fire the unit.
7.
Repeat this process with each gas valve.
Checking manifold gas pressure
The gas regulator on the combination gas valve is adjustable to
supply the proper manifold pressure for normal operation. The
gas valves are factory pre-set and should not need adjusting in
most cases. Gas manifold pressures are listed in Table 9B.
Gas manifold pressures may be checked with the use of a
manometer. Follow the steps in the Checking Combustion Air
Pressure Section prior to checking the manifold pressures.
1.
Turn the appliance power switch to the “OFF” position.
2.
Remove the upper outer access panels.
3.
Remove the 1/8” hex plug from the downstream side of
the gas valve (see FIG. 9-4). Install a fitting in the tap
and connect a hose from the tap to a manometer.
4.
Connect a hose from the tee used to measure the
combustion air pressure to the other side of the
manometer.
5.
Turn the appliance power switch to the “ON” position.
6.
With the unit at high fire, check and record the
manifold pressure of the valve. The manifold pressure
will be the sum of the two pressure readings (reference
Table 9B).
7.
Figure 9-4_Measuring manifold gas pressure
MANIFOLD
PRESSURE
Overfire and underfire hazards!
Possible fire, explosion, overheating,
and component failure. Do not attempt
to adjust firing rate of the appliance.
The firing rate must be adjusted only by
factory trained personnel.
If you must adjust the gas valve regulator pressure,
follow the steps below:
1.
Remove the cap covering the manifold pressure
adjustment screw (see FIG. 9-4). Note: Once the cap
is removed, the pressure shown on the manometer will
change and the unit may turn off.
2.
Make a slight adjustment to the manifold pressure
adjustment screw. Turning the screw clockwise
increases manifold pressure and counterclockwise
decreases manifold pressure.
66
PRESSURE
REGULATOR
ADJUSTMENT
(UNDER CAP
SCREW)
INLET
CHAMBER
PRESSURE
TEE
OUTLET
GAS
VALVE
CONTROL
KNOB
MANOMETER
Repeat this process with each gas valve.
 WARNING
pressure.
TO BARBED
FITTING
TABLE 9B
Net Manifold Pressure
Regulator Pressure Less
Front Chamber Pressure
MODEL
400 - 750
1000 - 2100
Nat. Gas
1.8'' w.c.
1.2'' w.c.
LP
4.6" w.c.
4.6" w.c.
Installation & Service Manual
9
Maintenance
(continued)
Inspect and clean the heat exchanger
1.
While burners are removed, check the heat exchanger
surface for sooting. If present, heat exchanger must be
cleaned and problem corrected. Proceed as follows.
2.
Remove gas manifold(s)/orifice assemblies as described in
steps 1 through 5 in Inspect and Clean Burner, page 64.
3.
Disconnect wiring from the hot surface igniter and
hose from the burner pressure tap.
4.
Remove inner jacket panel mounting screws and slide
door assembly out toward front of the unit. Use
caution to prevent damage to the refractory and hot
surface igniter.
5.
Check “V” baffles and frame runners along front
and back edges of heat exchanger. Remove and clean if
necessary.
6.
Remove soot from heat exchanger with a stiff bristle
brush. Use a vacuum to remove loose soot from
surfaces and inner chamber.
7.
The heat exchanger can be removed by sliding towards
the front of the unit. Once the heat exchanger is
removed from the unit, a garden hose can be used
to wash the tubes to ensure that all soot is removed
from the heat exchanger surfaces. Note: Do not wet the
unit’s refractory.
8.
Ensure that all burner ports are cleaned to remove any
soot. See Inspect and Clean Burner, page 64.
9.
Carefully reinstall the heat exchanger, “V” baffles, and
frame runners if removed from the unit. Note: Make
sure frame runners seal securely where they contact the
front and rear compartment refractory.
10. Carefully reinstall inner jacket panels, burners,
manifolds, wires and hoses. Use new gasket material to
ensure a proper air seal.
IMG00601
HEAT
EXCHANGER
Figure 9-5_Location of the Heat Exchanger Inside
Jacket
Review with owner
1. Emphasize the need to perform the maintenance schedule
specified in this section.
2. Remind the owner of the need to call a licensed contractor
should the appliance or system exhibit any unusual behavior.
3. Remind the owner to follow the proper shutdown procedure
and to schedule an annual start-up at the beginning of the
next heating season.
Oiled bearing circulators
Inspect the pump every six (6) months and oil as necessary. Use
SAE 30 non-detergent oil or lubricant specified by the pump
manufacturer.
11. Reassemble all gas and water piping. Test for gas leaks.
NOTICE
Upon completion of any testing on the gas
system, leak test all gas connections with a
soap and water solution while main burners
are operating. Do not spray soap and water
solution on the control module housing.
The use of an excessive amount of soap
and water solution can damage the control.
Immediately repair any leak found in the
gas train or related components. Do not
operate an appliance with a leak in the gas
train, valves, or related piping.
12. Reassemble outer jacket panels.
13. Cycle unit and check for proper operation.
67
Installation & Service Manual
10
Connection diagram
SILENCING ALARM
SWITCH BELL
BL
PR
PR
1
1
2
2
BL
24VAC
PR
PR/BK
BL
PR
Y
O
R
BL/W
P
RUN
TIME
RUN
24VAC
P
BL
PR
PR
OUTLET
SENSOR
OPERATOR
1
4
2
5
3
6
24VCOM
Y
4
1
5
2
6
3
Y
24VCOM
W
O
R
PR
BR
BR/W
PR
ARM
24VAC
T
INLET
SENSOR
24VAC
TD RLY
ALARM
CONTACTS
BR
BR
PR
BL
BR/W
PR/
BK
O
O/BK
Y
24VCOM
ALARM & RUN TIME CONTACTS
12 24V COM (-)
24V (+) 24
11 N/A
ALARM 23
10 N/A
N/A 22
N/A 22
9 IN/OUT COM
N/A 22
8 INLET SENSOR
N/A 22
7 OUTLET SENSOR
6 TANK SENSOR STAGE 2 OUT 18
5 N/A
STAGE 2 IN 17
STAGE 1 OUT 16
4 TANK COM
STAGE 1 IN 15
3 N/A
2 HEAT DEMAND PUMP OUT 14
PUMP IN 13
1 DEMAND COM
2-STAGE THERMOSTAT
BL
24VAC
PR
R/W
O
T
BL
R
O/BK
24VAC
LOUVER PROVING
LOUVER RELAY
LOUVER
PROVING
SWITCH
T/W
LOUVER
CONTACTS
W
T
120VAC
BR
BK
GY
1
BR
24V OUT
24V IN
2
1
2
3
3
4
4
FIELD SUPPLIED
WIRING
TANK
SENSOR
+
3
4
5
6
7
8
9
10
+
+
+
+
+
+
+
+
+
4
T
SYSTEM/TANK
SENSOR
GY
B2 INTERMITTENT
B1 LIMITS
A2 CONTINUOUS
A1 LIMITS
2 NO HIGH FIRE
2 C ENABLE
1 NO LOW FIRE
1 C ENABLE
6
1
7
2
8
3
9
4
10
5
BL
O
P
BL/W
R
T/W
24VAC
PR/
BK
PR
CHASSIS
GROUND
GROUND
120VAC
W
BK
120VAC
BK/W
W
-
BK
+
BK/W
120VNEU
1 S2/FS
GY
O/BK
R/W
R/BK
BK
3
2
O
O/BK
BR/W
BR/W
F1
F2
5 S1
GY
T/W
CONNECTION BOARD
1
2
-+
BK/W
W 120VNEU
10
9
8
7
6
5
4
TH
PI
Y
O
24VCOM
RESET
BL
MV
PS
M/S
1 FF
24VAC
IGNITION
MODULE
G
G
GROUND
G
G
O/BK
BR
PUMP IN
BR
NEUTRAL
W
FIELD SUPPLIED
WIRING
PUMP OUT
LINE
68
R/BK
120VNEU
BK
R
120VAC
C NO NC
BK
MAIN TERMINAL
BLOCK
T
BK/W
GW
C NO
24VCOM
Y
HIGH/LOW FIRE
RELAY SOCKET
TOP VIEW
R
BK
BK
BR BR
ON/OFF
SWITCH
24VCOM
C
12
NC
NO
PUMP RELAY
24VAC
R/BK
R/BK
2
Installation & Service Manual
10
Connection diagram
1
2
3
PR
RESET
PR
LWCO
CONNECTOR
LWCO
24VAC
T
T
TO PREVENT ELECTRICAL SHOCK
THIS HEATER MAY BE CONNECTED TO MORE THAN ONE BRANCH CIRCUIT. MORE THAN ONE
DISCONNECT SWITCH MAY BE REQUIRED TO DE-ENERGIZE THE EQUIPMENT FOR SERVICING.
O/BK BL
4 5 6
1 2 3
O
LWCO
PROBE
~~~~
3
1
4
2
Notes:
1. All wiring must be installed in accordance with: local, state, provincial and national code requirements
per either N.E.C. in USA or C.S.A. in Canada.
2. If any original equipment wire as supplied with the appliance must be replaced, it must be replaced
with wire having same wire gauge (AWG) and rated for a minimum of 105°C
3. Actual connector block locations may vary from those shown on diagrams. Refer to actual
components for proper connector block locations when using diagrams to trouble shoot unit.
B
Y
~~~~
~~~~
HI/LO GAS
O
O/BK
1
1
2
2
O
O/BK
A
FLOW
SWITCH
O
1
1
2
2
FLOW
SWITCH
BK
R
GY
1
1
GY
G
2
2
G
GY
3
3
GY
3
6
9
2
5
8
1
4
7
R
R/
BK
O
O
1 C 2
NC C NO
INDICATES
DOTTED LINE
INDICATES OPTIONAL
EQUIPMENT
W = WHITE
T=TAN
BK = BLACK
Y=YELLOW
PR=PURPLE
BR=BROWN
G=GREEN
BL=BLUE
GY=GRAY
P=PINK
R=RED
O=ORANGE
Y/G = YELLOW WITH GREEN STRIPE
120V
BK
BL
BL
BK W BL Y
G
T
24VAC
XFMR.
24V
CIRCUIT
BREAKER
ITEM
W
Y
MAIN UNIT
CONNECTOR
IGNITER
CONNECTOR
O
120VAC
120VNEU
24VCOM
24VAC
R
Y
W
24V COMMON
GROUND
BK
DISPLAY
BOARD
R
P
GY
GY
R
BK
R/BK
Y
1 C 2
NC C NO
BL
BL/W
PR/BK
W
O
O/BK
1 2
24VCOM
24VAC
BK
OPTIONAL
O
1
2
3
4
5
6
7
8
9
10
11
12
RST1
ALR
S2S2+
S2
S1
P1
OPTIONAL
IGN1
IGN1
AUX
HI-LIMIT
O
DANGER
!
CHASSIS
GROUND
TEST
(continued)
1 2 3 4
LOW
GAS
HIGH
GAS
NO COM NC
NO COM NC
1 2 3 4
HI/LO
SPEED
BLOWER
1 2
HI-LIMIT
O/BK
O/BK
O/BK
O
G
W
BK R W G
O
O
24VCOM
S2
T
O
4
2
3
1
Y
BL
S1
B
24VCOM
LWCO
CONNECTION
24VAC
BK
R
AIR
SWITCH
24VCOM
9
8
7
P
STAGE #2
2
A
STAGE #1
R/BK
1
R
O
MAIN UNIT
CONNECTOR
R/BK
STAGE #1
Y
Y
6
3
5
4
Y
2
R
1
O
W
R/BK
BLOCKED
FLUE SWITCH
T
G
20VNEU
O
O/BK
HSI
GY
R
Y
1
R
Y
2
STAGE #2
R/BK
Y
2
Y
BURNER
GROUND
OPTIONAL
LOW GAS
GY
1
STAGE #2
STAGE #1
G
OPTIONAL
OPTIONAL
OPTIONAL
LBL20331 REV B
69
Installation & Service Manual
11
Ladder diagram
GROUNDLINE
WHERE POSSIBLE, SW
UTILITIES
(GAS,
W
CONNECTED TO THE UN
MAY VARY FROM TH
DEPENDING
UPON
CONNECTED OR FAULT
CONNECTION DIAGRAM
WARNING:
THIS
HEATER
MAY
BE
CONNECTED TO ONE OR MORE BRANCH CIRCUITS.
NEUTRAL
TO PREVENT ELECTRICAL SHOCK, ENSURE ALL
BRANCH CIRCUITS ARE DE-ENERGIZED BEFORE
ATTEMPTING TO SERVICE THIS EQUIPMENT.
120 VAC
15AMPS
60Hz
G
W
CHASSIS
GROUND
BK
1
BK
2
BK
MAIN TERMINAL
BLOCK
ON/OFF SWITCH
GROUND
W
120
VAC
PUMP IN
BR
NO
24 BL
VAC
Y
LINE
24VCOM
CONTINUOUS
LIMITS
A1
A2
5
6
BL
BL
Y
24VCOM
24V
C
P
Y
NEUTRAL
9
10
14 PUMP
O/BK
S1
IN
S1
16
OUT
S2
17
IN
O
18
R
S2
OUT
2-STAGE
THERMOSTAT
R/W
PR
7
O
INLET
SENSOR
BR
BR
OUTLET
SENSOR
PR
PR
24VCOM
Y
Y
1
TANK
SENSOR
FIELD
WIRING
2
CONNECTION
BOARD
BR/W
BR
PR
BR/W
BR/W
OR/BK
Y
O
OPERATOR
12 24V COM (-)
11 N/A
10 N/A
9 IN/OUT COM
8 INLET SENSOR
7 OUTLET SENSOR
2
5
4
6
2
5
4
1
2
3
4
1
2
3
4
O
24V (+) 24
BL
BL
N/A 22
N/A 22
N/A 22
STAGE 2 OUT 18
4 TANK COM
3 N/A
STAGE 1 OUT 16
STAGE 2 IN 17
STAGE 1 IN 15
2 HEAT DEMAND
PUMP OUT 14
1 DEMAND COM
PUMP IN 13
2-STAGE THERMOSTAT
PR
24V
ALARM 23
N/A 22
6 TANK SENSOR
5 N/A
Y
TH
DIS
R/BK
8
6
3
BL
2C 2NO
CHASSIS
GROUND
3
1
FIELD SUPPLIED
SAFETY DEVICES
HIGH FIRE
Y
1
INTERMITTENT
LIMITS
B1 B2
O/
O
BK
3
4
STAGE #2
DOTTED LINE
INDICATES OPTIONAL
EQUIPMENT
W = WHITE
T=TAN
BK = BLACK
Y=YELLOW
PR=PURPLE
BR=BROWN
G=GREEN
BL=BLUE
GY=GRAY
P=PINK
R=RED
O=ORANGE
Y/G = YELLOW WITH GREEN STRIPE
70
2
HD
WIRES CROSS
GW
15
O/BK
O/BK
Y
TEST
~~~~
~~~~
~~~~
LOW FIRE
1C 1NO
FIELD SUPPLIED
SAFETY DEVICES
BL
PROBE
T
3
PUMP RELAY
24VAC COIL
STAGE #1
INDICATES
JUNCTION POINT
(ELECTRICALLY SAME)
2
GROUND
TO POWER
SOURCE
LWCO
1
BR
W
PUMP OUT
ITEM
BK
CIRCUIT
BREAKER
G
MAIN TERMINAL BLOCK
BK
RESET
UNIT PUMP
R/W
R
O
OR/BK
T
BL
Installation & Service Manual
11
Ladder diagram
WITCHES ARE SHOWN WITHOUT
WATER
OR
ELECTRICITY)
NIT. AS SUCH, SWITCH STATES
HOSE SHOWN ON DIAGRAM
WHETHER
UTILITIES
ARE
T CONDITION IS PRESENT. SEE
M FOR ADDITIONAL NOTES.
(continued)
PROVING
SWITCH
LOUVER
PROVING
TO POWER
SOURCE
W LM
T/W
T
IMPORTANT:
FOLLOW WIRING
INSTRUCTIONS INCLUDED
WITH KIT WHEN MAKING
POWERED VENTER
CONNECTIONS.
W
BR
LOUVER
CONTACTS
BK
24V IN
24V OUT
LV
BR
BK
1
LOUVER TERMINAL BLOCK
BLOCKED FLUE SWITCH
C
2
1
O
O
1
2
2
1
O
1
O
2
1
2
1
2
O/BK
!
-
NC
4
GY
3
TRIAL
O
MANUAL
RESET
HI-LIMIT
C
NC
2
GY
IGNITER
GY
O
+
F1
F2
-
LINE
NEU
1 S2/FS
O
O
DANGER
TO PREVENT ELECTRICAL SHOCK
HIS HEATER MAY BE CONNECTED TO MORE THAN ONE BRANCH CIRCUIT. MORE THAN ONE
SCONNECT SWITCH MAY BE REQUIRED TO DE-ENERGIZE THE EQUIPMENT FOR SERVICING.
10
+
AIR PRESS
SWITCH
(NOT ON 500)
LOW
HIGH
T/W
ALARM
BL
W
BLOWER
R
BK
W
G
W
W
HIGH
IGNITION
MODULE
HIGH FIRE VALVE(S)
R
PURGE
TH
PI
24COM
RESET
24VAC
MV
R
PS
R/BK
9
8
7
6
5
4
3
2
1 FF
RESET
P
NO
C
W
BK/
W
BK/
BK/
W
W
W
STATUS
BK
11
O
4
W
5 S1
GY
~~~
~~~
LoGas
3
BK
BURNER
GROUND
FACTORY
O/BK FLOW
SWITCH
C NO
3 4
T T/W
T
NC
NO
O/BK
1 2
C
P
AUX.
HI-LIMIT
HiGas
LoGas
2
LOW FIRE VALVE(S) Y
Y
R
R
Y
LOW
Y
R
R/BK
PR
6
6
PR/BK
ARMING RELAY
5
5
PR
ARM
Y
PR/
BK
Y
NO
BL
4
4
BL
R
3
3
R
BL
T
O
2
2
O
1
1
Y
TD
BL/W
C
NC
RUN
RUN
C
Y
TIME
DELAY
Y
Y
P
P
1
2
PR
2 PR
SILENCING
ALARM
SWITCH
BELL
+
Y
BL
1
+
PR
PR
C
NC
NO
Y
H/L
HIGH/LOW FIRE RELAY
PR/BK
+
+
ALARM
CONTACTS
RUN-TIME
CONTACTS
LBL20332 REV C
71
Installation & Service Manual
Notes
72
Installation & Service Manual
Notes
73
Installation & Service Manual
Notes
74
Installation & Service Manual
12
Warranty
LIMITED WARRANTY
A. O. Smith Corporation, the warrantor, extends the following LIMITED WARRANTY to the owner of this hot water supply boiler:
1.
If within FIVE years after initial installation of the hot water supply boiler, a heat exchanger or gas burner shall prove upon examination by the warrantor to be
defective in material or workmanship, the warrantor, at his option will exchange or repair such part or portion.
a. This warranty is extended to the owner for all other parts or portion during the FIRST year following initial installation of this hot water supply boiler.
b. The warranty on the repair or replacement of the part or portion will be limited to the unexpired term of the original warranty.
2. CONDITIONS AND EXCEPTIONS
This warranty shall apply only when the h o t water supply boiler is installed in accordance with local plumbing and building codes, ordinances and
regulations, the printed instructions provided with it and good industry practices. In addition, a pressure relief valve, certified by C.S.A. and approved
by the American Society of Mechanical Engineers, must have been installed and fresh water used for filling and make-up purposes.
a. This warranty shall apply only when the hot water supply boiler is used:
(1) with inlet water temperature 140°F (60°C) and above and outlet water temperatures not exceeding the maximum setting of its operative and/
or high limit control;
(2) at water pressure not exceeding the working pressure shown on the hot water supply boiler;
(3) when filled with water, free to circulate at all times and with the heat exchanger free of damaging scale deposits;
(4) in a non-corrosive and non-contaminated atmosphere;
(5) in the United States, its territories or possessions, and Canada;
(6) at a water velocity flow rate not exceeding or below the hot water supply boiler’s designed rates;
b. Any accident to the hot water supply boiler, any misuse, abuse (including freezing) or alteration of it, any operation of it in a modified form, or any attempt
to repair leaks in the heat exchanger will void this warranty.
3. SERVICE AND REPAIR EXPENSE
Under this limited warranty the warrantor will provide only a replacement part. The owner is responsible for all other costs. Such costs may include but are
not limited to:
a. Labor charges for service, removal, repair, or reinstallation of the component part;
b. Shipping, delivery, handling, and administrative charges for forwarding the replacement part from the nearest distributor and returning the claimed defective
part to such distributor.
c. All cost necessary or incidental for any material and/or permits required for installation of the replacement.
4. LIMITATIONS ON IMPLIED WARRANTIES
Implied warranties, including any warranty of merchantability imposed on the sale of this hot water supply boiler under state or provincial law are limited to one
(1) year duration for the hot water supply boiler or any of its parts. Some states and provinces do not allow limitations on how long an implied warranty lasts,
so the above limitation may not apply to you.
5. CLAIM PROCEDURE
Any claim under this warranty should be initiated with the dealer who sold the hot water supply boiler, or with any other dealer handling the warrantor’s
products. If this is not practicable, the owner should contact:
U.S. Customers
Canadian Customers
A. O. Smith Corporation
A. O. Smith Enterprises Ltd.
P. O. Box, 310 - 768 Erie Street
500Tennessee Waltz Parkway
Ashland City, TN
Stratford, Ontario N5A 6T3
Telephone: 800 527-1953
Telephone: 800-265-8520
a. The warrantor will only honor replacement with identical or similar parts thereof which are manufactured or distributed by the warrantor.
b. Dealer replacements are made subject to in-warranty validation by warrantor.
6. DISCLAIMERS
NO OTHER EXPRESS WARRANTY HAS BEEN OR WILL BE MADE ON BEHALF OF THE WARRANTOR WITH RESPECT TO THE MERCHANTABILITY OF
THE HOT WATER SUPPLY BOILER OR THE INSTALLATION, OPERATION, REPAIR OR REPLACEMENT OF THE HOT WATER SUPPLY BOILER. THE
WARRANTOR SHALL NOT BE RESPONSIBLE FOR WATER DAMAGE, LOSS OF USE OF THE UNIT, INCONVENIENCE, LOSS OR DAMAGE TO PERSONAL
PROPERTY, OR OTHER CONSEQUENTIAL DAMAGE. THE WARRANTOR SHALL NOT BE LIABLE BY VIRTUE OF THIS WARRANTY OR OTHERWISE
FOR DAMAGE TO ANY PERSONS OR PROPERTY, WHETHER DIRECT OR INDIRECT, AND WHETHER ARISING IN CONTRACT OR TORT.
a. Some states and provinces do not allow the exclusion or limitation of the incidental or consequential damage, so the above limitations or exclusions may
not apply to you.
b. This warranty gives you specific legal rights, and you may also have other rights which vary from state to state or province to province.
Fill in the following for your own reference. Keep it. Registration is not a condition of warranty. The model and serial number are found on the hot water supply boiler’s rating plate.
Owner
Installation Address
City and State
Date Installed
Dealer’s Name
Zip Code
Model No.
Serial No.
Phone No.
Dealer’s Address
FILL IN WARRANTY AND KEEP FOR FUTURE REFERENCE
75
Revision Notes: Revision A (ECO #C12846) initial release.
Revision B (ECO #C13498) edits made to the setpoint default on page
47, edits made to FIG. 7-6 and 7-7 on page 48 along with the addition
of new revisions of LBL20331 and LBL20332.
Revision C (C# 500001030) reflects the update of Table 4B on page 37,
as well as the addition of the factory startup label on the manual cover.
Revision D (PCP# 3000006580 / CN# 500006678) reflects a change
from all instances of “water heater” to “hot water supply boiler,” and
references to ANSI Z21.13. SAP material numbers have been updated.
GNS-I-S_MM# 100161041_DIR# 2000005371_Rev D
02/17