940 ESO
For Outdoor Installations Only
Temperature Modulated with Electronic Ignition
Suitable for heating potable water and space heating
(Intended for variable flow applications)
6720644956-00.1V
940 ESO - Natural Gas
940 ESO - Liquefied Petroleum (LP) Gas
6 720 644 956 (2010/09) US
Warning: If the information in this manual 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.
Improper installation, adjustment, 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.
In the Commonwealth of Massachusetts this
product must be installed by a licensed plumber or
gas fitter.
Upon completion of the installation, these
instructions should be handed to the user of the
appliance for future reference.
What to do if you smell gas
• Close gas valve. Open windows.
• 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.
• Installation and service must be performed by a
qualified installer, service agency or the gas supplier.
Index
Index
1
Warning
3
2
2.1
2.2
2.3
2.4
2.5
Appliance details
Features
Specifications (Technical data)
Unpacking the heater
General rules to follow for safe operation
Dimensions and Min. installation clearances
5
5
5
6
7
8
3
3.1
3.2
3.3
Installation requirements
Specialized tools
Introduction
Proper location for installing your heater
4
4.1
4.2
4.3
4.4
Installation using Outdoor Kit (BTOK)
Warnings
Installing outdoor vent cap on the appliance
Selecting heater location
Mounting instructions
10
10
10
12
13
5
5.1
Installation using the Recess
Box (7 736 500 043)
Heater placement and clearances
14
14
6
6.1
6.2
6.3
6.4
6.5
6.6
Installation instructions
Gas piping & connections
Water connections
Water quality
Domestic hot water recirculation
Space heating applications
Measuring gas pressure
17
17
20
20
21
22
24
7
7.1
7.2
Electrical connections
Electrical power supply
Position of the fuses in control unit
25
25
25
Operation instructions
Description of LCD display
For your safety read before operating
your water heater
8.3 Power
8.4 Temperature selection
8.5 Use of optional remote control accessory
(part no. TSTAT2)
8.6 Operation
8.7 Reset button
8.8 Fan speed
8.9 Program button
8.10 Locked condition
26
26
8
8.1
8.2
2
9
9
9
9
9
9.1
9.2
9.3
9.4
9.5
9.6
Maintenance and service
Annual maintenance
Winterizing for seasonal use
Mineral scale build-up
Adjusting CO2
Program values
Control board diagnostics
31
31
32
32
33
35
36
10
Troubleshooting
10.1 Introduction
10.2 Burner does not ignite when hot
water is turned ON
10.3 Water is too hot
10.4 Water is not hot enough
10.5 Low water flow/pressure
10.6 Hot water temperature fluctuates
or goes cold at tap
10.7 Noisy burner/heater during operation
37
37
38
38
11
Problem solving
11.1 Error code diagnostics
39
39
12
Electrical diagram
43
13
Sensor resistance charts
44
14
GWH 940 ESO Functional scheme
46
37
37
37
38
15
Interior components diagram
and parts list
15.1 Interior components
15.2 Components diagram
47
47
49
16
17
55
56
Protecting the environment
Limited Warranty
27
27
27
28
28
28
29
31
31
6 720 644 956
Warning
1
Warning
For your safety
Do not store or use gasoline or other flammable,
combustible or corrosive vapors and liquids in the
vicinity of this or any other appliance.
Warning: Carefully plan where you
install the heater. Correct installation
location and proper combustion air
supply air supply are very important. If a
gas appliance is not installed correctly,
fatal accidents can result, such as
carbon monoxide poisoning or fire.
Warning: Exhaust gas must be vented
to outside.
Warning: Field wiring connections and
electrical grounding must comply with
local codes, or in the absence of local
codes, with the latest edition of the
National Electric Code, ANSI/NFPA 70,
or in Canada, all electrical wiring must
comply with the local codes and the
Canadian Electrical Code, CSA C22.1
Part 1.
Warning: Shock hazard: line voltage is
present. Before servicing the water
heater, unplug power supply cord from
outlet. Failure to do so could result in
severe personal injury or death.
Warning: The heater must be
disconnected from the gas supply
piping system during any pressure
testing of that system at test pressures
equal to or more than 0.5 psig.
Warning: The appliance should be
located in an area where leakage of the
heater or connections will not result in
damage to the area adjacent to the
appliance. When such locations cannot
be avoided, it is recommended that a
suitable drain pan, adequately drained,
be installed under the appliance. The
pan must not restrict combustion air
flow.
Warning: The maximum inlet gas
pressure must not exceed the value
specified by the manufacturer and the
minimum value listed is for the purpose
of input adjustment.
Warning: If a water heater is installed in
a closed water supply system, such as
one having a backflow preventer in the
cold water supply line, means shall be
provided to control thermal expansion.
Contact the water supplier or local
plumbing inspector on how to control
this situation.
Warning: Keep appliance area clear
and free from combustible materials,
gasoline and other flammable vapors
and liquids.
Warning: Do not obstruct the flow of
combustion and ventilation air.
Warning: Precautions must be taken
prior to manually operating the relief
valve to avoid contact with hot water
coming out of the relief valve and to
prevent water damage.
Caution: Label all wires prior to
disconnection when servicing controls.
Wiring errors can result in improper and
dangerous operation.
Verify proper operation after servicing.
Warning: If a relief valve discharges
periodically, this may be due to thermal
expansion in a closed water supply
system. Contact the water supplier or
local plumbing inspector on how to
correct this situation. Do not plug the
relief valve.
Warning: If the water heater is used in
a space heating application, all piping
and components connected to the
water heater must be suitable for use
with potable water.
Warning: Toxic chemicals, such as
those used for boiler treatment, shall not
be introduced into the potable water
used for space heating.
6 720 644 956
3
Warning
Warning: A water heater which will be
used to supply potable water shall not
be connected to any heating system or
component(s) previously used with a
nonpotable water heating appliance.
FCC:
This device complies with Part 15 of the FCC rules.
Operation is subject to the following two conditions: (1)
This device may not cause harmful interference, and (2)
this device must accept any interference received,
including interference that may cause undesired operation.
DANGER
HOT
BURN
Water temperature over 125°F can
cause severe burns instantly or
death from scalds.
Children, disabled and elderly are
at highest risk of being scalded.
See instruction manual before
setting temperature at water
heater.
Feel water before bathing or
showering.
6720608643-16.1AL
Fig. 1
4
6 720 644 956
Appliance details
2
Appliance details
2.2
Specifications (Technical data)
Approved in US/Canada
2.1
Features
Capacity
Maximum flow rate: 7.15 GPM (27 l/min) at a 45°F
(25°C) rise.
Parts
•
Key Pad interface control
• High power pre-mix compact burner with low NOx
emissions
• Modulating Gas Valve with constant gas:air ratio
control
• Modulating water valve for improved comfort and
temperature control.
High quality materials for long working life
• Copper heat exchanger
Maximum output
160,500 Btu/h (47.0 kW)
Maximum input
199,000 Btu/h (58.3 kW)
Efficiency in %
Thermal efficiency > 82%
Min. Input
• High efficiency Ceramat Burner
19,900 Btu/h (5.8 kW)
• Compact space saver: mounts on a wall with a
supplied bracket.
Temperature Control
Selection range: 100°F (38°C) - 140°F (60°C)
Features
• Real-time
diagnostics
informational purposes
for
troubleshooting/
Default temperature: 122°F (50°C)
Stability: +/- 2°F (+/- 1°C)
• LCD Display with backlight
Gas Requirement
• On/Off and Temperature control switches
Gas connection (inches) - ¾”
• Reset button
• Program button (Selectable temperature default)
Inlet gas pressure under operation (with a high hot
water flow rate)*
• Failure codes for easy diagnostics and repair
• Propane: 8” - 13” water column
• Easily removable one-piece cover
• Natural Gas: 3.5” - 10.5” water column.
• Built in freeze prevention1).
* To measure gas pressure, see Measuring Gas
Pressure, chapter 6.6, page 24.
Accessories (Bosch part #)
• Optional wireless remote control accessory to
operate with the appliance (TSTAT2)
• Cascading kit (7709003962)
• External water filter (8703305356)
• Gas conversion kit (8719002176)
• Pipe Cover (PTPCES)
• Recess box (7736500043)
• Pressure relief valve (FWL-2).
i
BOSCH is constantly improving its
products, therefore specifications are
subject to change without prior notice.
Water
• Hot water connection (inches) - ¾”
• Cold water connection (inches) - ¾”
• Water valve material: Polymer (PPS) (Polypropylene
Sulfid)
• Minimum water flow: 0.5 gallon/minute (1,9 l/m).
Note: Activation varies with inlet water temperatures
from 0.5 - 1.6 gallon/minute (1.9 - 6.1 l/m).
• Minimum recommended water pressure: 30 PSI
(2.07 bar).
• Minimum well pressure 40 psi, see page 20.
• Connections:
– Bottom of heater
Combustion
1) The freeze prevention kit is designed to provide
protection for the water heater down to approximately
5°F for short term conditions only. It will not protect the
appliance in areas where the temperature is routinely
expected to be below freezing.
- The freeze prevention kit will not protect plumbing
outside the appliance from freezing. Precautions should
be taken.
6 720 644 956
• NOx ≤ 40 Ng/J (Nanograms of NOx (calculated as NO2) per
Joule of heat output).
• CO ≤ 250 ppm (measured)
• CO2 level set from factory, see chapter 9.4, page 33.
5
Appliance details
Dimensions
2.3
• Depth (in): 11¼” (286 mm)
In order for proper installation, this water heater
must be installed with the outdoor kit (BTOK)
accessory.
Before installing the unit, be certain you have the
correct heater for your type of Gas: Propane or
Natural Gas. Identification labels are found on
the shipping box, and on the rating plate which is
located on the right side panel of the cover.
• Width (in): 17 7/8” (452 mm)
• Height (in): 30½” (775 mm)
• Weight: 67 pounds (30.5 kg).
Gas types
Natural Gas.
LP Gas.
Unpacking the heater
Voltage
120 V AC (60 Hz) nominal
Amperage
Idle - 40 mA
Operation - ≤ 2.5 A
Noise
45 - 65 db (A)
Safety devices
• Flame failure device (ionization flame rod sensor)
• Over heat prevention (temperature limiter)
Fig. 2
Rating plate
Serial number
Type of gas
• Inlet temperature sensor
A
B
• Outlet temperature sensor
The box includes:
• Back flow temperature sensor.
• 940 ESO
Water protection
• Bracket for wall hanging the heater
IP X4 (protection against water drops)
• Installation manual (manual can be downloaded at
www.boschpro.com)
i
If appliance is installed at elevations above
2000ft, refer to Section 8.8.1 Fan speed
adjustment.
• Product registration card
• Energy Guide label (in the front cover).
Please complete and return the enclosed product
registration card.
The 940 ESO is not approved or designed for:
• Manufactured (mobile) homes, boats or any
mobile installation. (Modular homes are
acceptable for installation).
• Use above 8000 ft A.S.L. altitude (see page 29).
• Outdoor installation without installation of
Outdoor kit (BTOK) or Recess Box (7 736 500
043).
• Applications where inlet water temperature is
higher than 140ºF (60°C). A 3-way valve or
mixing valve must be installed before the
appliance if inlet water temperature exceeds
this limit.
6
6 720 644 956
Appliance details
2.4
To remove front cover
B Loosen the two Phillips head screws located on
bottom rear of cover (see Fig. 3).
6720644956-02.1V
Fig. 3
Loosen the two screws
B Lift front cover panel upward and remove.
2
2
1
6720644956-13.1V
1
Fig. 4
Remove the front cover
To remove combustion cover (service only)
B Open the four clips and remove the combustion
cover see Fig. 5.
General rules to follow for safe
operation
B 1. You must follow these instructions when you install
your heater. In the United States: The installation must
conform with local codes or, in the absence of local
codes, the National Fuel Gas Code ANSI Z223.1/
NFPA 54.
In Canada: The Installation must conform with CGA
B149.(1,2) INSTALLATION CODES and /or local
installation codes.
B 2. Carefully plan where you install the heater. If not
installed correctly, fatal accidents can occur, such as
carbon monoxide poisoning or fire.
B 3. The water heater must be installed outdoors using
the outdoor kit and/or recess box accessory.
B 4. You must vent your heater so that the exhaust
gases discharge to the outdoors.
B 5. The appliance and its gas connection must be leak
tested before placing the appliance in operation.
The appliance must be isolated from the gas supply
piping system by closing its individual manual gas
shutoff valve (not supplied with heater) during any
pressure testing at pressures in excess of ½ Psig (3.5
kPa).
B 6. Keep water heater area clear and free from
combustibles and flammable liquids. Do not locate
the heater over any material which might burn.
B 7. Correct gas pressure is critical for the proper
operation of this heater. Gas piping must be sized to
provide the required pressure at the maximum output
of the heater, while all the other gas appliances are in
operation. Check with your local gas supplier, and
see the section on connecting the gas supply, see
chapter 6.1.
B 8. Should overheating occur or the gas supply fail to
shut off, turn off the gas supply at the manual gas shut
off valve, on the gas line. Note: manual gas shutoff
valve is not supplied with the heater but must be field
installed.
B 9. Do not use this appliance if any part has been
underwater. 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 underwater.
B 10. Failure to install heater correctly may lead to
unsafe operation and void the warranty.
6720644956-14.1V
Fig. 5
Remove the combustion cover
6 720 644 956
7
Appliance details
Dimensions and Minimum installation clearances
6 ½"
4 1 16" 5 ¼"
16"
2 1 16
7
8
"
11 ¼"
5 ¼"
30 ½"
17
16"
2 55 16
6 5 16"
2 ¾"
2.5
1
+
reset
6
P
3
4
7
5 ¼"
2
5
6720644956-01.1V
Fig. 6
1
2
3
4
5
6
7
8
Dimensions
On/Off button
Reset button
Program key
Power ON or stand-by LED
LCD display
Up button
Down button
6 720 644 956
Installation requirements
3
Installation requirements
3.1
Specialized tools
The following specialized tools may be required for
installation:
• Manometer
• Multi-meter
• Combustion Gas Analyzer.
3.2
Introduction
Please follow these instructions. Failure to follow
instructions may result in:
B Damage or injury.
B Improper operation.
B Loss of warranty.
If you are unable to perform the tasks required to install
this heater properly, please contact a locally licensed
plumber or gas technician.
3.3
Proper location for installing your
heater
Carefully select the location of the water heater. For
your safety and for proper heater operation, follow the
guidelines below:
B 1. Locate the heater where gas and plumbing
connections are feasible and convenient.
B 2. The hot water lines should be kept short and
insulated to save energy. Centrally locating the water
heater is recommended to keep hot water
distribution times even throughout the structure.
Warning: The water in this water
heater is cold and always remains cold
except for the times the burner is on. In
the event of power outage in
conjunction with freezing temperatures,
it is recommended that the heater be
drained.
See chapter 9.2, page 32 “Winterizing”
for draining instructions.
Warning:
Flammable
materials,
gasoline, pressurized containers, or any
other items or articles that are potential
fire hazards must NOT be placed on or
adjacent to the heater. The appliance
area must be kept free of all
combustible materials, gasoline and
other flammable vapors and liquids.
6 720 644 956
9
Installation using Outdoor Kit (BTOK)
4
Installation using Outdoor Kit (BTOK)
4.1
Warnings
Danger: the water in this appliance is
cold and always remains cold except for
the times when the burner is on. In the
event of power outage in conjunction
with freezing temperatures, it is
recommended that the heater be
drained.
Danger: The top of the outdoor kit will
get very hot during operation. Keep
away from children. Install heater in a
location where the top of the kit cannot
be reached by small children.
Danger: Flue gas will be released
through the outdoor kit. Flue gas is very
hot and contains carbon monoxide. The
outdoor kit cannot be installed on a
water heater mounted indoors. To
prevent risk of fire and carbon monoxide
poisoning, maintain all clearances
indicated in these instructions.
Warning: Damage to the appliance
from freezing is not covered under the
manufacturer's warranty.
Outdoor kit (BTOK) includes:
• Supports (2) with screws
• Sealing gasket
• Control panel shield
Danger: Do not place or store any
combustible material within 5 feet of the
appliance. Maintain specified clearance
to combustibles on the wall where the
appliance is installed and any adjacent
walls or overhang. Observe all
clearances required in this manual.
• Outdoor vent cap.
4.2
Installing outdoor vent cap on the
appliance
Replace the control panel shield
B Loosen the two Phillips head screws located on
bottom rear of cover (see Fig. 3).
Danger: Surface temperature of the kit
is less than 140°F, except highest top
surface which may reach 300°F.
Warning: Do not mount water heater
directly onto vinyl siding, see Fig. 14.
6720644956-02.1V
Danger: the freeze prevention kit on
the appliance is designed to provide
protection from temperatures down to
approximately 5°F for short term
conditions only. It will not protect the
appliance in areas where the
temperature is routinely expected
to be below freezing. The freeze
prevention kit will not protect plumbing
outside the appliance from freezing.
Precautions must be taken:
B Always drain the water heater if it will be
exposed to long term freezing conditions.
10
Fig. 7
Loosen the two screws
Warning: The control panel shield
must always remain closed, except
when making adjustments, to prevent
damage to heater from weather.
B 1. Attach the supports (A) to the appliance by fastening with the four provided screws, as shown in Fig. 8.
6 720 644 956
Installation using Outdoor Kit (BTOK)
A
A
6720644956-03.1V
Fig. 8
Before mounting the outdoor kit in the appliance:
B 3. Attach the gasket provided with the kit as shown
in Fig. 9.
6720645551-11.1V
Fig. 10
B Attach the outdoor vent cap to the appliance by fastening the two provided screws and washers, see
Fig. 11.
6720645551-15.1V
Fig. 9
B Position the outdoor vent cap on the top of the
appliance, as shown in Fig. 10.
6720645551-12.1V
Fig. 11
i
6 720 644 956
NOTE: Once this kit is installed, the
outdoor vent cap will need to be removed
before removing the front cover.
11
Installation using Outdoor Kit (BTOK)
4.3
Selecting heater location
Before proceeding, read the water heater installation
manual. If the information in that manual is not followed
exactly, a fire, explosion or poisoning by carbon monoxide may result causing property damage, personal injury
or death.
B Choose an outside wall for the installation.
Installation on a wall protected by an overhang above
is recommended.
i
Best practice note: The clearances in
Fig. 12 and table 1 are the minimum
allowed by the standard.
When possible consider maximizing the
clearances A, B, C, D and E to allow for
the effects of wind and frequently used
door and window openings.
B Size the water and gas connections according to the
instructions in the water heater installation manual.
Use unions when connecting both water lines and
gas supply line to the heater.
Minimum clearances
If the appliance is installed under an overhang, there
must be a 36” clearance from the top of the appliance
and the mounting area must be open in front and on the
sides of the appliance.
D
E
B
A
G
C
F
6720645551-10.1V
Fig. 12
Ref.
Description
Min.
distances
A
≥ 1 ft
C
Directly below or adjacent to
an opening; operable
windows, doors and any fresh
air openings
D
From any adjacent wall
≥ 1 ft
E
Below a gutter, sanitary
pipework, eaves or overhang
≥ 3 ft
F
Above ground
≥ 1 ft
B
From a gas meter or gas
regulator
Table 1 Clearances
G
12
≥ 3 ft
6 720 644 956
Installation using Outdoor Kit (BTOK)
4.4
Mounting instructions
B The water heater is approved for installation directly
on an outside wall. Secure the wall mounting bracket
provided with the water heater to a wall surface. See
Fig. 13.
B The installation method of the mounting bracket will
depend on the type of mounting surface. Due to the
varieties of building siding or surfacing, the installer
must decide on how best to support and level the
heater on an outside wall. It is recommended that
horizontal or vertical support boards or plywood
sheathing (1/2” minimum) first be attached to the
wall surface. The heater must also be kept level on
the wall surface.
3½’
Vinyl siding
³1
2”
³12”
³1
2”
4’
Wood or
non-plastic
material
Plywood (½" minimum)
or other solid wood
material(s) to anchor the
wall support bracket and
keep the heater level
against wall surface
Fig. 14 Installation on vinyl siding
Wood
siding
6 7
2 0
6 0
8 5
4 7
-0 8
.1 J
S
Fig. 13 Installation on wood siding
Warning: Do not mount heater directly
to vinyl siding. With vinyl siding, a 3½' x
4' area of the siding must first be
removed and then replaced with wood
or other non-plastic material. See
Fig. 14.
6 720 644 956
13
Installation using the Recess Box (7 736 500 043)
5
Installation using the Recess
Warning: Improper installation!
This recess box has been designed to be
mounted in a wall cavity with exhaust vent
discharging to the outdoors. Do not install
the recess box in another configuration.
Damages resulting from an improper installation will not be covered by Bosch limited
warranty.
Box (7 736 500 043)
Heater placement and clearances
Warning: The water heater with recess
box accessory is intended for an outdoor installation only.
The water heater is approved for installation on a
combustible wall (see chapter 4.4 Mounting
installation) provided the floor covering below
the heater is noncombustible. For installations in an
alcove or closet, maintain the minimum clearances to
combustible and non-combustible materials. See
chapter 2.5, page 8.
5.1.1
Wall cavity
Dimensions of Recess Box
When building the wall cavity for the recess box, make
preparations for the water and gas lines and electrical
wires as well.
(540)
(293)
5.1
Do not install the Recess box:
• Under a deck or patio.
• Side of the building with prevailing winter winds.
(303)
• Close to plants or trees.
• In areas where people or animals can accidentally
touch louvered exhaust openings.
1
(1197)
(1170)
4
The Recess box should be installed so the discharge
vent maintains the minimum allowable clearances as
required by the local authority. Where no local requirement exists, maintain the following minimum suggested
clearances from builing openings as shown in Fig. 15.
4
• Maintain a clean area in front of the appliance of 4
feet (1,2m).
(564)
(303)
1
(293)
1
6720644960-02.1V
3
Fig. 16 Recess box dimensions in inches (mm)
12
6720644960-01.1V
Fig. 15 Discharge vent clearances
i
14
Top, front, and side clearances noted on
the front cover of the water heater are not
applicable when installed in a Recess box.
6 720 644 956
Installation using the Recess Box (7 736 500 043)
1
4
2
5
6
3
6720644960-03.1V
Fig. 17 Recess box plumbing/electrical openings
1
2
3
4
5
6
Hot water opening
Pressure relief valve opening
Electrical opening
Cold water opening
Gas opening
Condensing opening1)
B Secure the wall mounting bracket provided with the
heater to the wall surface. The heater must be kept
level on the wall surface, see Fig. 19, page 15.
6720644956-05.1V
Fig. 19 Leveling the mounting bracket and screwing
the recess box on the studs
6720644956-04.1V
Fig. 18 Support boards
B Hang water heater on wall mounting bracket. Ensure
heater is level.
Caution: Ensure the outdoor kit
(BTOK) accessory has been installed on the water heater prior to
operating -see section 4.2.
6720644956-06.1V
Fig. 20 Mounting the heater inside recess box
1) Not used with this appliance.
6 720 644 956
15
Installation using the Recess Box (7 736 500 043)
6720644956-08.1V
Fig. 21 Close the recess box cover with Padlock
Warning: Appliance must be installed
vertically.
16
6 720 644 956
Installation instructions
6
Installation instructions
6.1
Gas piping & connections
Before connecting the gas supply, check the rating
plate on the right side of the heater to be sure that the
heater is rated for the same gas to which it will be connected.
In the United States: The installation must conform with
local codes or, in the absence of local codes, the
National Fuel Gas Code ANSI Z223.1/NFPA 54.
In Canada: The Installation must conform to CSA B149
INSTALLATION CODES and/or local installation
codes.
Warning: DO NOT connect to an
unregulated or high pressure propane
line or to a high pressure commercial
natural gas line.
Warning: The heater must be isolated
from the gas supply piping system
during any pressure testing of that
system at test pressures equal to or
more than 0.5 psig. If overpressure has
occurred, such as through improper
testing of the gas lines or malfunction of
the supply system, the gas valve must
be checked for safe operation.
Minimum
3”
Gas supply
Cap
Fig. 22 Gas connection (drip leg)
Once connections are made, check for gas leaks at all
joints. Apply some gas leak detection solution to all gas
fittings. Bubbles are a sign of a leak. A combustible gas
detector may also be used to detect for leaks.
Danger: If you have a leak, shut off the
gas. Tighten appropriate fittings to stop
leak. Turn the gas on and check again
with a gas leak detection solution.
Never test for gas leaks using a match
or flame.
GAS CONNECTIONS
B Install a manual gas shut off valve on the gas supply
line within easy reach of the appliance.
B Install a union when connecting gas supply.
B The minimum internal diameter required for
any appliance connector is ¾”, see Fig. 24 for
more details on pipe sizing.
B Undersized flexible appliance connector not permitted.
B National Fuel Gas Code requires that a sediment
trap (drip leg) be installed on gas appliances not so
equipped. The drip leg must be accessible and not
subject to freezing conditions. Install in accordance
with the recommendations of the serving gas
supplier, see Fig. 22.
6 720 644 956
17
Installation instructions
GAS LINE SIZING
The gas supply piping for a single heater should be
sized for a maximum draw of 199,000 BTUH. Measure
the length of gas supply line and use the tables in
Fig. 24, page 19 or the gas line manufacturer’s sizing
tables to determine the pipe diameter necessary to
accommodate the 199,000 BTU demand of the heater.
If there are more gas appliances on the line, size the gas
line according to the total maximum amount of BTU
input rating for all appliances.
Note: Undersizing the gas line may result in diminished
hot water flow rate and temperature. See chapter 6.6,
page 24 for the procedure to confirm gas pressure.
Proper gas pressure must be confirmed at time of
installation.
Gas piping
Inlet gas particle screen
(included)
Fig. 23
18
6 720 644 956
Installation instructions
FOR NATURAL GAS
Maximum Capacity of pipe in Cubic Feet of Gas per Hour for Gas Pressure of 0.5 Psig or less and a Pressure drop
of 0.3” in Water Column (0.75mbar).(Based on a 0.60 Specific Gravity Gas) Btu numbers given in thousands.
Follow boxed numbers for piping just one 940 ESO (example: ¾” B.I. Natural Gas pipe for 10 ft (3.0m). will
handle 278,000 btu’s (81.5 kWh). For multiple appliances combine the total maximum btu input load and then
refer to applicable chart below.
Nominal
Length of Black iron Pipe , Feet
Iron
Pipe
Internal
Size,
Diameter
inches
inches
10
20
30
40
50
60
70
80
90
100
125
150
175
200
1/4
0.364
32
22
18
15
14
12
11
11
10
9
8
8
7
6
3/8
0.493
72
49
40
34
30
27
25
23
22
21
18
17
15
14
1/2
0.622
132
92
73
63
56
50
46
43
40
38
34
31
28
26
3/4
0.824
278
190
152
130
115
105
96
90
84
79
72
64
59
55
1
1.049
520
350
285
245
215
195
180
170
160
150
130
120
110
100
1 1/4
1.380
1050
730
590
500
440
400
370
350
320
305
275
250
225
210
1 1/2
1.610
1600
1100
890
760
670
610
560
530
490
460
410
380
350
320
2
2.067
3050
2100
1270 1150 1050
990
930
870
780
710
650
610
1650 1450
Length of Flexible Corrugated Stainless Steel Tubing (CSST), Feet
Tube
size,
inches
EHD*
10
20
30
40
50
60
1/2
18 EHD 82
58
47
41
37
34
3/4
23 EHD 161
116
96
83
75
68
1
30 EHD 330
231
188
162
144
131
1 1/4
37 EHD 639
456
374
325
292
267
* EHD = Equivalent Hydraulic Diameter. The greater the
value of EHD, the greater the gas capacity of the tubing.
FOR LP GAS
Maximum Capacity of Pipe in Thousands of BTU per Hour of Undiluted Petroleum Gases (at 11 inches Water Column Inlet
Pressure) (Based on a Pressure Drop of 0.5 Inch Water Column).
* EHD = Equivalent Hydraulic Diameter. The greater the
value of EHD, the greater the gas capacity of the tubing.
Lengt h of Flexible Corrugat ed St ainless St eel Tubing (CSST), Feet
Nominal
Black Iron Pipe
iron
Length of Pipe, Feet
pipe
10
20
30
40
50
60
80
100
125
150
200
1/2
291
200
160
137
122
110
94
84
74
67
58
3/4
608
418
336
287
255
231
197
175
155
140
120
1145 787
632
541
480
434
372
330
292
265
227
Inches
1
Maximum
Capacity
of
Semi-Rigid
(flexible,
Tube
size
inches
EHD*
10
20
30
40
50
1/2
18 EHD 129
91
74
64
58
3/4
23 EHD 254
183
151
131
118
1
30 EHD 521
365
297
256
227
non
corrugated) Tubing in Thousands of BTU per Hour of
Undiluted Liquefied Petroleum Gases (at 11 inches
Copper
Length of Tubing, Feet
Outside
diameter
Inch
10
20
30
40
50
60
70
80
Water Column Inlet Pressure).
3/8
39
26
21
19
_
_
_
_
90 100
_
_
(Based on a Pressure Drop of 0.5 Inch Water Column)
1/2
92
62
50
41
37
35
31
29
27
26
* Source National Fuel Gas Code NFPA 54, ANSI
Z223.1 - No Additional Allowance is necessary for an
ordinary number of fittings
5/8
199 131
107
90
79
72
67
62
59
55
3/4
329 216
181 145
131
121 112 104
95
90
Fig. 24
6 720 644 956
19
Installation instructions
6.2
Water connections
Warning: This heater is not approved
for preheated water applications above
140°F (60°C). See chapter 6.4 for
approved recirculating application.
Warning:
In applications where inlet water
temperature can exceed 140°F (60ºC), a
3-way valve or mixing valve must be
installed before the appliance to prevent
water exceeding 140°F (60°C) from
entering the appliance.
B When facing the heater, the ¾” cold connection is on
the bottom right and the hot connection is on the bottom left. Centrally locating the water heater is recommended to keep hot water distribution times even
throughout the structure.
B Plastic or PEX type plumbing line materials are not
suitable for connecting directly to the water heater.
B Although water piping throughout the building may
be other than copper, we recommend that copper or
suitably rated stainless steel flex line piping be used
for the water connections for 1.5’ on either side of
the water heater (follow local codes if more
stringent).
B Never sweat any piping directly to or beneath
the water connections, as damage can occur to
the internal water valve from heating of the
pipe.
B Keep water inlet and outlet pipes to no less
than ¾" (19.05mm) diameter to allow the full
flow capacity.
B If the cold and hot connections to the heater are
reversed, the heater will not function. Be certain there
are no loose particles or dirt in the piping. Blow out
or flush the lines before connecting to the water
heater.
B Full port shutoff valves should be installed on both
the cold water supply and hot water outlet lines to
facilitate servicing the heater (see Fig. 27).
B For installation on a private well system with the use
of a pressure tank, the lowest pressure range setting
recommended is 40-60 psi (2.75 and 4.15 bar).
6.3
COLD
HOT
Fig. 25
Water quality
Water quality can have an impact on appliance
longevity and may not be covered under the
manufacturer's warranty.
For water analysis data call your local water department,
or if on a well, have well water analyzed periodically. If
water quality exceeds one or more of the values
specified below, Bosch recommends consulting a local
water treatment professional for water softening/
conditioning options.
Description
pH
6.5 - 8.5
TDS (total Dissolved
mg/l or ppm
500
Total hardness
mg/l or ppm
100
Aluminum
mg/l or ppm
2.0
Chlorides
mg/l or ppm
250
Copper
mg/l or ppm
1.0
Iron
mg/l or ppm
0.3
Manganese
mg/l or ppm
0.05
Zinc
mg/l or ppm
5.0
pH
Fig. 26 Water filter
1
2
Water valve with engine
Water filter
B The use of unions when connecting both water
pipes to the inlet and outlet connections is
required. This will facilitate any necessary
servicing.
20
Max. Levels
Table 2
6 720 644 956
Installation instructions
Connecting the pressure relief valve (PRV)
6.4
A listed pressure relief valve must be installed at the
time of installation. No valve is to be placed between
the PRV and the heater. No reducing coupling or
other restriction may be installed in the discharge line.
The discharge line must be a minimum of 4” above a
drain and installed such that it allows complete drainage
of both the PRV and the line. The discharge line must be
placed where it will not cause any damage.
The location of the PRV must be readily accessible for
servicing or replacement, and be mounted as close to
the water heater as possible. See Fig. 27. To install the
PRV, a suitable fitting connected to an extension on a
“T” fitting can be sweated to the hot water line.
Support all piping.
Although recirculation directly through the tankless
water heater is allowed, temperature stability is
improved by recirculating through a mini-tank as shown
in Fig. 28. By using the design in Fig. 28, there is no
recirculation of hot water through the tankless water
heater and therefore, does not affect the heat
exchanger warranty. Direct recirculation through the
tankless water heater is permissible, however, the heat
exchanger warranty is reduced; contact Bosch
Thermotechnology for further installation requirements.
The following drawing is provided to outline one
possible recirculation design using the water heater in
conjunction with an Ariston mini tank water heater. This
schematic is for illustration only and must not be used
for actual installation without appropriate engineering
and technical advice from a properly licensed
professional in the locality where the installation is
made.
Domestic hot water recirculation
940
ESO
5
2
4
1
3
Fig. 27 Plumbing Connections (with shutoff valves)
and Pressure Relief Valve
6720608158-77.1AL
Ariston Minitank
Fig. 28 Recirculation application
1
2
3
4
5
Full port isolation valve
Circulator (pump on timer)
Check valve
PRV
Expansion tank
The use of a small electric mini-tank water heater (4-6
gallon size) should be used for this application and
designed so the pump will circulate the water through
the mini-tank and the building's hot water return loop
only. Timed or thermostatically controlled operation of
the pump is commonly done. Contact Bosch
Thermotechnology if further information is needed.
6 720 644 956
21
Installation instructions
6.5
Space heating applications
Warning: If the set point temperature is
above 120 F means should be undertaken to protect users of potable water
from scalding.
Warning: ensure the primary pump is
sized to provide adequate flow for the
system heat load.
i
Warning: Propylene glycol may be
used for freeze prevention ONLY on the
space heating side of the heat exchanger. Do not use ethylene glycol (automotive antifreeze).
Warning: The use of a flow switch may
be used to ensure DHW priority and to
prevent “cold-blow” situations when the
Bosch tankless water heater is used
with an air-handling system. The flow
switch should be used to disable the
blower on the air-handling system when
domestic water is used.
For Pump sizing please refer to the
pressure drop curves, Fig. 29. Also
remember to account for system piping
pressure loss. Recommendation for
primary pump size for adequate flow
through the water heater (minimum of 1.7
GPM).
Bosch tankless water heaters are allowed to be used in
combination DHW and space heating applications
(open-loop setup). It is not allowed to use Bosch
tankless water heater in a space heating only
application (closed-loop setup). Bosch supports
combination DHW and space heating in an open loop
configuration if plumbed similar to Fig. 30. Use of a
Bosch tankless water heater in a combination DHW
and space heating application will result in the product
warranty being reduced to 3 years.
940ESO
70
60
Pressure (Feet of Head)
50
40
30
20
10
0
0.0
1.0
2.0
3.0
Flow (GPM)
4.0
5.0
6720644956-15.1V
Fig. 29 Pressure drop curve
22
6 720 644 956
Installation instructions
8
18
13
17
T
5
7
12
22
16 15
1
11
21
14
9
5
20
9
10
2
3
6
9
5
4
6720644887-02.1V
19
Fig. 30 Space heating diagram
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Hot water outlet
Cold water inlet
Pressure relief valve
Gas supply
Shut off gas valve
Thermal expansion tank (as required)
Atmospheric vacuum breaker
Cold inlet
Check valve
Pump
Thermostatic mixing valve
Thermometer (optional)
DHW outlet
Water to water heat exchanger
Backflow preventer
Automatic water feed
Thermostat
Space heating zone
Zone controller
Space heating pump
Expansion tank
Pressure relief valve
6 720 644 956
23
Installation instructions
6.6
Measuring gas pressure
B Record lowest operating gas pressure reading in
table 4.
Confirm gas pressure upon installation.
Connecting manometer
B Shut off gas supply at installer supplied shutoff valve
for this water heater.
B Remove front cover and locate inlet gas pressure
measuring point (see Fig. 32).
B Loosen screw inside left test point fitting (do not
remove) and connect manometer tube to test point.
Remove screw completely if correct size tapping is
available.
Static Pressure Test
B Turn gas supply back on.
B Record static gas pressure reading in table 4.
Gas pressures lower than 3.5" W.C. for Natural Gas or
8" W.C. for LPG will result in insufficient degree rise to
the hot water being used, reduced hot water volume,
possible error code faults and must be corrected. See
Gas Connections, chapter 6.1, page 17.
P1 fan speed:
Factory default: NG: 48, LP: 46
Lowering P1 fan speed reduces the maximum BTU
input.
As a temporary measure if the gas pressure in P1 is
below specification, lower P1 fan speed incrementally
until minimum inlet gas pressure reaches specified
range (table 3). After upgrading gas line, reset
appliance to P1 factory default setting (NG: 48, LP: 46)
or setting from Section 8.8.1.
Operating Pressure Test
B Press ON/OFF button to turn off the appliance.
B Press and hold "Program" (P) button and press ON/
OFF button to turn appliance ON.
Fig. 32 Gas pressure test port (left tapping)
Static Gas Pressure Reading (see Chapter 6.6)
Fig. 31
B As soon as '188' is displayed, release "Program"
, button and the display should read P2.
B Press
or
enter here: ___________________ Date: ___________
Operating Gas Pressure Reading (see Chapter 6.6)
until P1 appears.
Note: While in this mode the appliance will run
constantly at maximum power and allow
maximum water flow.
enter here: ___________________ Date: ___________
Table 4
For inlet gas pressure adjustment consider the
following table:
Gas type
NG
LPG
pin
3.5” WC
8” WC
Table 3
Minimum inlet gas pressure under full operation
B Turn on high volume of hot water flow (at least 6
gpm) and heater will ignite. If heater display reverts to
P2, open more hot water fixtures to allow sufficient
flow. Press
until P1 reappears on display.
B Operate all other gas appliances (except this heater)
on same gas piping system at maximum output.
24
6 720 644 956
Electrical connections
7
Electrical connections
7.1
Electrical power supply
7.2
Warning:
For
safety
reasons,
disconnect the power supply cord to
the heater before any service or testing
is performed.
Warning: This heater must be
electrically grounded in accordance
with the most recent edition of the
National Electrical Code. NFPA 70. In
Canada, all electrical wiring to the
heater should be in accordance with
local codes and the Canadian Electrical
Code, CSA C22.1 Part 1. Do not rely
on the gas or water piping to ground the
metal parts of the heater.
The water heater requires an electrical power supply
from a 120VAC / 60Hz properly rated receptacle and
must be properly grounded.
The heater is wired as shown in the wiring diagram
(chapter 12, Fig. 60).
Position of the fuses in control unit
To check fuses, proceed as follows:
B Remove the front cover, see Fig. 4, page 7.
B Remove the three screws on front of the control unit.
Fig. 34
B Pull control unit free to access and remove the six
screws from the back cover of the control unit, see
Fig. 35, pos. 2.
B Check the fuses in the printed circuit board, see Fig.
35, pos. 3.
1
6720608643-15.1AL
1
Fig. 33
Note: Outlet appliance is plugged in to should be clear
from possible water damage.
2
3
6720608158-78.1AL
Fig. 35 Location of fuses
B After verifying the fuses mount all parts in reverse
order.
6 720 644 956
25
Operation instructions
8
Operation instructions
Fig. 36
1
2
3
4
5
6
7
8.1
On/Off button
Reset button
Program Key
LCD display
Up button
Down button
LED - Power On indicator or Stand-by
Description of LCD display
Warning: Do not use any cleaning or
corrosive agent to clean the window.
Fig. 40 Lock indicator (only with remote control)
Fig. 41 Flame indicator
Fig. 37 Power bar indicator (input)
Fig. 42 Solar mode indicator (see chapter 8.4, page
27)
Fig. 38 Temperature indicator
Fig. 43 Remote control indicator
Fig. 39 Error indicator
26
6 720 644 956
Operation instructions
8.2
For your safety read before
operating your water heater
Warning: If you do not follow these
instructions exactly, a fire or explosion
may result causing property damage,
personal injury or loss of life.
8.4
Temperature selection
To select output water temperature:
B Press buttons
temperature.
or
in order to reach desired
A. This appliance is equipped with electronic ignition for
lighting the main burner. When turning the heater on,
follow these instructions exactly.
B. Before operating the unit, press the On/Off button.
WHAT TO DO IF YOU SMELL GAS
B Do not try to light any appliance.
B Do not touch any electric switch; do not use any
phone in your building.
Fig. 45
B Immediately call your gas supplier from a neighbors
phone. Follow the gas supplier’s instructions.
Setting the water temperature
B If you cannot reach your gas supplier, call the fire
department.
C. Use only your hand to press the on/off control switch.
Never use tools. Follow these instructions exactly. If
control switch is jammed, close the gas supply and call
a qualified service technician. Attempted forceful 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.
8.3
Power
The desired temperature of the hot water can be
adjusted on the front control panel of the heater.
The water heater has an electronically controlled gas
valve that modulates the burner input in response to
both varying hot water flow rates and/or changes in any
incoming and outgoing water temperatures.
Saving water resources:
B Make sure you close all the taps after any use. Avoid
leaving the taps dripping. Repair any leaking tap.
B Define the temperature you want, in the appliance or
with the remote control. This way you have the
precise water flow needed (mixing cold water to
regulate temperature will increase the water flow with
consequent waste of water)
On
B To start the appliance press the On/Off button.
Fig. 44
Off
B To shut down the appliance press the On/Off button
again.
6 720 644 956
27
Operation instructions
Solar mode
The water heater will not ignite if inlet water temperature
exceeds the set temperature on the appliance. In this
condition, the solar mode indicator will show on the
LCD display. See Fig. 42, page 26.
Warning:
In applications where inlet water
temperature can exceed 140°F (60ºC), a
thermostatic or mixing valve must be
installed before the appliance to prevent
water exceeding 140°F (60°C) from
entering the appliance.
control unit (Fig. 72, component 16) is required when
programming the remote control with this heater.
i
8.6
NOTE: up to 6 remote controls can be
programmed for one single water heater,
each with a range distance of 98 ft (30 m).
Operation
B When a hot water tap is opened, main burner ignites
and LCD displays the symbol
.
DANGER
Fig. 48
B LCD blinks until selected temperature is reached.
HOT
8.7
BURN
Water temperature over 125°F can
cause severe burns instantly or
death from scalds.
Reset button
If the LCD shows the error symbol
do not shut off
power or unplug the heater.
See the error code on LCD and consult
“Troubleshooting” section.
Children, disabled and elderly are
at highest risk of being scalded.
See instruction manual before
setting temperature at water
heater.
Feel water before bathing or
showering.
Fig. 49
6720608643-16.1AL
After
following
instructions
“Troubleshooting” section.
Fig. 46
8.5
Use of optional remote control
accessory (part no. TSTAT2)
indicated
in
B press reset firmly in order to return heater to normal
operation.
Fig. 50 Reset button
If the problem persists, contact your installer.
Fig. 47 Remote control
The wireless remote control accessory (Fig. 72,
component 13) and the temperature selector buttons
on the front of the water heater operate identically.
Contact your distributor to order the remote control
accessory. Modification of the water heaters interior
28
6 720 644 956
Operation instructions
8.8
Fan speed
8.8.1
Fan speed adjustment
IMPORTANT! Installation adjustment:
After installing the water heater, the fan speed values for
minimum power (P2) and maximum power (P1) may
need adjustment due to variations in altitude.
Failure to make necessary adjustments to fan speed
values may result in improper operation of the
appliance.
Use the equivalent vent length value to determine the
appropriate fan speed value found in the Table 5. Refer
to page 29 on how to adjust the fan speeds if an
adjustment is necessary. After changing fan speed
values, proceed to section 9.4 to confirm CO2 values
are within specified ranges.
Fan speed adjustment
Natural Gas
Altitude
(above sea
Liquid propane
Minimum power Maximum power fan Maximum power fan
fan speed (P2)
speed (P1)
speed (P1)
No
No
0 - 2000 ft
7
modification required
modification required
(0 - 610 m)
For operation at elevations above 2,000
ft (610 m) the equipment ratings shall
2000 - 4500 ft
8*
48*
47*
be reduced at the rate of 4% for each
(610 - 1372 m)
1,000 ft (305 m) above sea level
4500 - 8000 ft
48*
9*
49*
(1372 - 2439 m)
* Above 2000 ft, CO2 levels must be checked with a combustion gas analyzer, see section 9.4 for instructions.
Table 5
Fan speed adjustment
Adjusting minimum power fan speed (P2)
Adjusting maximum power fan speed (P1)
To select fan speed:
To select fan speed:
B Press ON/OFF button into OFF.
B Press ON/OFF button into OFF.
B Press and hold "Program" button
ON/OFF button to turn appliance ON.
and press
B Press and hold "Program" button
and press
ON/OFF button to turn appliance ON.
Fig. 51
Fig. 52
B As soon as '188' is displayed, release "Program"
button
, and the display should read P2.
B As soon as '188' is displayed, release "Program" button
, and the display reads P2.
B Press
or
to choose the fan speed suitable
with your installation, see Table 5.
B Press the minus button
B Press and hold (± 5 sec.) “Program” button
until
the display flashes, then the selected value is memorized.
i
Do not set P2 to greater then 9.
B Press
or
to choose the fan speed suitable
with your installation, see Table 5.
B Press and hold (± 5 sec.) “Program” button
until
the display flashes, then the selected value is memorized.
i
6 720 644 956
to display P1.
B Press “Program” button
to enter P1 adjustment.
The current setting will appear on the display.
Proceed directly to Section 9.4 to confirm
CO2 values are within range.
29
Operation instructions
Attention residents of the Commonwealth of
Massachusetts:
signage installed in accordance with the provisions of
248 CMR 5.08(2)(a)1 through 4.
In the Commonwealth of Massachusetts the following
regulation went into effect on 12/30/2005:
(b) EXEMPTIONS: The following equipment is exempt
from 248 CMR 5.08(2)(a)1 through 4:
(a) For all side wall horizontally vented gas fueled
equipment installed in every dwelling, building or
structure used in whole or in part for residential
purposes, including those owned or operated by the
Commonwealth and where the side wall exhaust vent
termination is less than seven (7) feet above finished
grade in the area of the venting, including but not limited
to decks and porches, the following requirements shall
be satisfied:
1. The equipment listed in Chapter 10 entitled
"Equipment Not Required To Be Vented" in the most
current edition of NFPA 54 as adopted by the Board;
and
1. INSTALLATION OF CARBON MONOXIDE
DETECTORS. At the time of installation of the side wall
horizontal vented gas fueled equipment, the installing
plumber or gasfitter shall observe that a hard wired
carbon monoxide detector with an alarm and battery
back-up is installed on the floor level where the gas
equipment is to be installed. In addition, the installing
plumber or gasfitter shall observe that a battery
operated or hard wired carbon monoxide detector with
an alarm is installed on each additional level of the
dwelling, building or structure served by the side wall
horizontal vented gas fueled equipment. It shall be the
responsibility of the property owner to secure the
services of qualified licensed professionals for the
installation of hard wired carbon monoxide detectors.
a. In the event that the side wall horizontally vented gas
fueled equipment is installed in a crawl space or an at
tic, the hard wired carbon monoxide detector with alarm
and battery back-up may be installed on the next
adjacent floor level.
b. In the event that the requirements of this subdivision
can not be met at the time of completion of installation,
the owner shall have a period of thirty (30) days to
comply with the above requirements; provided,
however, that during said thirty (30) day period, a
battery operated carbon monoxide detector with an
alarm shall be installed.
2. APPROVED CARBON MONOXIDE DETECTORS.
Each carbon monoxide detector as required in
accordance with the above provisions shall comply with
NFPA 720 and be ANSI/UL 2034 listed and IAS
certified.
2. Product approved side wall horizontally vented gas
fueled equipment installed in a room or structure
separate from the dwelling, building or structure used in
whole or in part for residential purposes.
(c) MANUFACTURERS REQUIREMENTS - GAS
EQUIPMENT VENTING SYSTEM REQUIRED. When
the manufacturer of Product Approved side wall
horizontally mounted gas equipment provides a venting
system design or venting system components with the
equipment, the instructions provided by the
manufacturer for the installation of the equipment and
the venting shall include:
1. Detailed instructions for the installation of the venting
system or the venting system components: and
2. A complete parts list for the venting system design or
venting system.
(d)MANUFACTURER REQUIREMENTS - GAS
EQUIPMENT VENTING SYSTEM NOT PROVIDED.
When the manufacturer of a product approved side wall
horizontally vented gas fueled equipment does not
provide the parts for the venting of flue gases, but
identifies "special venting systems," the following
requirements shall be satisfied by the manufacturer:
1. The referenced "special venting system" instructions
shall be included with the appliance or equipment
installation instructions; and
2. The "special venting systems" shall be product
approved by the Board, and the instructions for that
system shall include a parts list and detailed installation
instructions.
(e) A copy of all installation instructions for all products
approved side wall horizontally vented gas fueled
equipment, all venting instructions, all parts lists for
venting instructions, and/or all venting design
instructions shall remain with the appliance or
equipment at the completion of the installation.
3. SIGNAGE. A metal or plastic identification plate shall
be permanently mounted to the exterior of the building
at a minimum height of eight (8) feet above grade
directly in line with the exhaust vent terminal for the
horizontally vented gas fueled heating appliance or
equipment. The sign shall read, in print size no less than
one half (1/2) inch in size, "GAS VENT DIRECTLY
BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS".
4. INSPECTION. The state or local gas inspector of the
side wall horizontally vented gas fueled equipment shall
not approve the installation unless, upon inspection, the
inspector observes carbon monoxide detectors and
30
6 720 644 956
Maintenance and service
8.9
Program button
Caution:
Program button can be used on the appliance and in the
remote control.
B Check and clean the complete water
heating system once a year.
Programming “Program” function
Programming actions are similar for both controls
(appliance control pad and wireless remote control).
B Carry out a maintenance overhaul if
necessary. Immediately repair defects to
avoid damage to the system.
Annual maintenance table
Every year
1. Inspect venting system
X
2. Inspect Combustion chamber
X
Fig. 53 “Program” key
3. Inspect burner
X
Memorizing selected temperature
4. Inspect water filter
X
B Press buttons
memorized.
or
to select temperature to be
B Hold “Program” button for 3 seconds to save
temperature.
When LCD stops blinking, temperature is saved in
memory.
Using “Program” function
In order to select memorized temperature
B Press “Program” key.
LCD shows pre-memorized temperature, which is now
the hot water selected temperature.
8.10 Locked condition
This condition is only valid for appliances with one or
more remote controls installed.
Fig. 54 Locked condition
Whenever LCD shows
the temperature setting
cannot be adjusted because the appliance is in use by
a user which already selected a different temperature.
Appliance will be automatically unlocked after closing
the hot water tap.
9
Maintenance and service
Warning: Always turn off the electrical
power supply, turn off the manual gas
shut off valve and turn off the water shut
off valves whenever servicing.
6 720 644 956
Table 6
Annual maintenance
The unit should be checked once a year by a gas
technician. If repairs are needed, the repairs should be
done by a gas technician.
9.1
Annual maintenance
(To remove front cover, see page 7.)
Venting System
• Venting system - remove outdoor vent cap and
inspect inside of flue pipe for any blockage or
restriction. Observe burner flames during heater
operation. Inspect the combustion air opening for
blockage or debris. Inspect outdoor vent cap louvers
for blockage or debris.
Combustion chamber
• Inspect burner observation window (Fig. 65, #10) for
cracks or spillage of flue gases. Observe burner
flames during heater operation. Flames should be
steady and blue with no signs of yellowing. Yellow
burner flames are an indication of improper
combustion. Refer to Section 3.3 of this manual to
ensure that exhaust system and combustion air
supply meets manufacturer's specifications.
Pressure relief valve
• Manually open the pressure relief valve to ensure
proper operation.
Inlet water filter
• Verify the inlet filter screen is clean and undamaged.
The inlet water filter is located above the ¾" cold
water inlet on the right side of the appliance (See
Fig. 26, page 20). Close installer supplied cold water
shutoff and supplied water shutoffs, carefully remove
inlet and outlet clips on watervalve. Remove water
valve to access filter. Clean or replace if damaged.
31
Maintenance and service
Descaling
• In areas where the water supply has a high mineral
content (see Table 2, page 20), the heat exchanger
should be periodically flushed with a descaling
solution. Scale build up will shorten the life of the
water heater and damage resulting from scale is not
covered under warranty. Refer to section 9.3 for
detailed instructions on descaling the heat
exchanger.
Fin coils
• Inspect heat exchanger fincoil for soot build-up or
blockage. To access fincoil outdoor vent cap must
be removed. With cap removed and inspect fincoil
below with a flashlight. If there is evidence of soot
build-up or blockage, the heat exchanger should be
removed by a professsional and cleaned thoroughly.
To remove the heat exchanger, consult service
bulletin at www.boschpro.com.
9.2
Winterizing for seasonal use
Installation instructions state that the water heater must
not be installed in a location where it may be exposed to
freezing temperatures. If the heater must be left in a
space which is likely to experience freezing
temperatures, all water must be drained from the heater.
If precautions are not taken, resulting damage will not
be covered under the warranty. NOTE: Use of agents
such as anti-freeze is not permitted as they may cause
damage to the water heater's internal components.
1. Press ON/OFF switch on the water heater to turn
OFF the heater and unplug power supply cord. The
display should be blank.
2. Shut off gas supply to heater.
3. Shut off the water supply to the water heater using
installer supplied shutoff valve.
4. Open hot water taps to drain the plumbing system. If
water continues to flow after 5 minutes, a plumbing
crossover is present and must be corrected before
proceeding.
5. Open service valves (if available) or disconnect inlet
and outlet water pipes from the water heater. Place a
small bucket underneath the water heater to catch
residual water remaining inside the water heater.
A7 and E9 and boiling sounds (knocking and banging)
in the heat exchanger.
Descaling using a pump
1. Disconnect electrical supply from the water heater.
2. Shut off the water supply to the water heater using
(installer supplied) shutoff valve.
3. Open hot water taps to drain and relieve pressure
from the plumbing system.
4. Drain water from the unit's heat exchanger by
disconnecting inlet and outlet water connections
from the heater.
5. Connect a line (A) from the outlet of the circulating
pump (installer supplied) to the inlet water fitting on
the water heater (see Fig. 55).
6. Using another line (B), connect to the water outlet
fitting on the water heater. Route the other end of this
line into a descaling reservoir.
7. Using a 3rd line (C) from the descaling reservoir,
connect to the inlet side of circulating pump. Install a
filter on the end of this line in the descaling reservoir.
8. Make sure all connections are "water tight.".
9. Fill tank with descaling solution so both lines inside
are submersed. We recommend straight white
vinegar. If using a commercial descalant, refer to
manufacturer's instructions on dilution with water.
10.Operate the circulating pump.
11.Make sure there are no leaks and the solution is
flowing from the descaling reservoir through the
heater and returning to the reservoir.
12.Run solution through the heater until the solution
returning to the descaling reservoir comes out clear.
(Changing to a fresh solution may be necessary
during this process).
13.Disconnect all lines and drain all solution from heat
exchanger. Properly discard of solution.
14.Position a container below the hot water outlet and
connect cold water supply. Open cold water supply
isolation valve and flush heat exchanger with clean
water.
15.Shut cold water shutoff valve and reconnect hot
water supply to the water heater.
6. Using an air compressor, blow short bursts of air
(100psi max) through the outlet water connection
until there is no water present coming through the
inlet water connection of the heater.
7. Reconnect water fittings and return heater to service
when danger of freezing has passed.
9.3
Mineral scale build-up
Periodic descaling may be necessary in areas with high
mineral content in the water. Scale buildup in the heat
exchanger may result in lower flow rates, error codes of
32
6 720 644 956
Maintenance and service
16.Reconnect electrical supply to unit, open water
shutoff valves, and return the unit to service.
B To access measuring port, remove two screws on
either side of the louvered grill.
B Pull louvered grill free from vent cap.
B Insert CO2 analyzer probe into the measuring port.
The tip of the probe should be in the center of the flue
pipe (approx 1.5" inserted). Avoid air gaps between
probe and measuring port as they can alter readings.
Warning: Outdoor vent cap will get
very hot during operation.
B Ensure the vent cap is cool before
performing the procedure below.
B When measuring is complete, replace louvered grill
with screws.
Fig. 55
9.4
Adjusting CO2
The CO2 can only be adjusted by a certified gas
technician with a calibrated CO2 analyzer.
i
CO2 adjustment is required in Natural
Gas installations where energy content
is less than 900 BTU/cuft, and in
installations with repeated unresolved
EA and EC errors (ref. to page 39
“Problem solving”).
Fig. 56
1
Measuring port
B While holding the Program (P) button in, press the
ON/OFF button to turn ON the heater (see Fig. 57).
As soon as ‘188’ flashes on the display, release the
Program button. The display should now read P2.
Press ‘
’ button until “P1” appears on display.
Caution: One factor that may affect
CO2 levels is improper gas pressure.
Please see Chapter 6.6 for the
procedure to measure gas pressure
and record your findings below:
Static Gas Pressure:
P1 Operating Pressure:
“ WC
“ WC
The P1 minimum operating gas pressure is 3.5" WC for
Natural Gas and 8" WC for Propane. Do not proceed in
adjusting CO2 until pressure is at or above these levels,
but not to exceed 10.5" WC for Natural Gas and 13"
WC for Propane.
Fig. 57
B. Measuring CO2 (combustion cover must be
installed):
A. Once Gas Pressure is adequate
B Open all hot water taps to achieve a flow rate of at
least 6 gallons per minute. (1 tub and 2 sinks should
be sufficient). If heater display reverts back to P2,
open more hot water fixtures to allow sufficient flow.
B Press ON/OFF button to turn off the heater.
B Press ‘
B To measure CO2 on this appliance, a measuring port
is available under the louvered grill on the front of the
outdoor vent cap.
B Record the CO2 reading in P1 below. (Analyzer
reading may take several minutes to stabilize).
6 720 644 956
’ until P1 reappears on display.
33
Maintenance and service
B Press the ‘
’ button until P2 appears. Unit will
ramp down to low fire and the flow should decrease.
B Record the CO2 reading in P1 and P2 below.
P2 CO2 Reading:
% CO2
P1 CO2 Reading:
% CO2
Note: When making adjustments,
combustion cover is installed.
CO2 range (%)
make
sure
3. Verify both P1 and P2 CO2 readings are within the
ranges specified in table 7. Repeat steps 1 and 2 as
necesssary until CO2 values are within the specified
ranges.
4. Once CO2 values are within the specified ranges,
verify the CO readings on P1 and P2 do not exceed
values shown in table 7. If values exceed this limit,
inspect vent system and fin coils (chapter 9.1, page 31)
for blockage.
D. Returning to Service:
Max. CO
level
(measured)
Nat. Gas
max. input
P1
7.5 % - 8.1 %
< 250 ppm
min. input
P2
2.3 % - 2.6 %
< 60 ppm
1. Return slotted screw cover to original position and
tighten Phillips screw.
2. Reinstall Torx cover.
3. Remove CO2 analyzer probe and reinstall flathead
screw with gasket in exhaust collar.
4. Press ON/OFF button to turn OFF the heater and
then turn ON the heater.
5. Heater is ready for normal operation.
LP Gas
max. input
P1
8.7 % - 9.3 %
< 250 ppm
min. input
P2
2.7 % - 3.0 %
< 60 ppm
* Values above are for climate controlled conditions.
Inputs such as gas pressure, heating value of the gas,
humidity and temperature of combustion air all impact CO
and CO2 values. Changes in these inputs can result in
different CO and CO2 values on the same appliance.
Table 7
Final Readings
P2 CO2 Reading:
% CO2
P1 CO2 Reading:
% CO2
CO2 & CO target numbers
C. Adjusting CO2:
Note: P1 adjustment will change the P2 reading.
Confirm the P1 value BEFORE adjusting the P2 level.
1. If P1 CO2 level is off:
B Loosen yellow painted Phillips screw (1) and cover
should rotate down (2) revealing a recessed brass
slotted screw. Fig. 58.
B Turning the slotted screw counter clockwise will
raise P1 CO2 levels and clockwise will lower P1
CO2 levels. Adjustments to the slotted screw will
also change P2 CO2 levels.
Fig. 58 Adjusting P1 CO2 level
B After bringing the P1 CO2 readings in proper range,
press the ‘
’ button to enter the P2 mode. Verify
CO2 readings in P2 mode.
2. If P2 CO2 level is off:
B Remove yellow painted #40 Torx cover from the front
of the gas valve. (Fig. 59) A plastic #40 Torx screw
will be revealed.
B Turning the plastic #40 Torx screw counter
clockwise will lower P2 CO2 levels and clockwise
will raise P2 CO2 levels.
6720608158-38.1AL
Note: This screw adjustment is very sensitive and
should be made in small increments. It may take several
minutes for readings to stabilize.
34
Fig. 59 Adjusting P2 CO2 level
6 720 644 956
Maintenance and service
9.5
Program values
This section describes details on programming the
appliance. For most applications, the factory default
values will provide robust and stable operation. Only
adjust the factory settings if the installation requires
changes as indicated in the appropriate section of this
manual.
Refer to chapter 9.6 Control board diagnostics (page
36) regarding how to access these P-modes.
Caution: Misadjusted program
values can lead to appliance
malfunction, errors, and service
calls.
Program
Description
Factory Default
MIN
MAX
Comment
P1
Maximum Power
NG:48,
LP:46
21
NG:50,
LP:49
see chapter 6.6, page 24.
note: reducing P1 values below
maximum will reduce maximum
power of the appliance.
P2
Minimum Power
7
7
20
see chapter 8.8.1, page 29
P3
Remote Controls installed
_0
_0
6
see chapter 8.5, page 28
P4
Access to Diagnostic Mode
E
0d
10f
see chapter 9.6, page 36
P5
Cascade Mode
NO
NO
CC
contact Bosch for details
P6
Temperature
Unit
°F
°F
°C
P7
Appliance Type
NO
Cd
NO
Condensing / Non-condensing*
P8
Back light
dE
dE
ON
dE turns back light off after 60
seconds from last button pushed,
ON
turns
backlight
on
permanently
P9
Fan Purge
PH
Cascading type
IC
IC
SC
PC
Master/Slave
mode
CS
CS
CM
Table 8
runs secondary and primary fan
when P9 is selected by
depressing the “P” - button
This menu is only available when
cascade mode is select CC.
Contact Bosch Water Heating for
details.
Program values, factory default settings and ranges.
* Incorrect setting causes errors.
6 720 644 956
35
Maintenance and service
9.6
Control board diagnostics
1. Turn on/off switch on water heater to off (O) position.
B Press and hold the program '
' button while
pushing the on/off button to the on (I) position. The
display will cycle through a startup procedure
including the software version.
B Release the '
' button when '188' appears on the
display. The display should read 'P2' when the
program button is released. If not, repeat process.
B Press and release the '
' button on the control
panel until the display reads 'P4'. You are now in the
diagnostic mode of the control board.
B When the display reads 'P4', press and release the
'
' button once again and the display should read
'E'.
B Use the '
to cycle
available.
' and '
through
' button on the control board
different diagnostic modes
B Once in the selected diagnostic mode of your
choice, press and release the '
' button to display
the diagnostic information.
B EXAMPLE: to read the flow rate in gallons per minute
while the unit is flowing water, cycle to the '3d' mode
and press the '
' button. A reading of 25 on the
display would indicate the heater is reading a flow
rate of 2.5 gallons/minute.
B Once the information is obtained, press the '
'
button again to return to the diagnostic mode menu
and scroll to addition diagnostic information.
B To exit the diagnostic mode of the heater, use the
'
' or '
' button until the display reads 'E'.
1F
Most recent error/failure
2F
2nd most recent error
3F
3rd most recent error
4F
4th most recent error
5F
5th most recent error
6F
6th most recent error
7F
7th most recent error
8F
8th most recent error
9F
9th most recent error
10F
10th most recent error
H0
Numbers of hours - mode 0
H1
Numbers of hours - mode 1
H2
Numbers of hours - mode 2
Table 9
9.6.1
Working hours
To see how many hours the appliance has worked,
please enter the “Diagnostic menu” (chapter 9.6);
B Select the sub-mode “H0”.
Write the number that shows in the display.
B Select the sub-mode “H1”.
Write the number that shows in the display.
B Select the sub-mode “H2”.
Write the number that shows in the display.
After checking the sub-modes H0, H1 and H2, introduce the values in the table below;
Working hours
B Press the '
' button once again and the display
should read P4.
Number in H0
______
_______ +
2. Press the on/off button off (O) and back on (I) again
to return heater to normal function.
Number in H1
______ (X 100) =
_______ +
Number in H2
______ (X 10 000) =
_______ +
(H0 + H1 + H2) = Total of hours
Diagnostic menu
_________
Table 10
E
Entry/Exit into sub-modes
Example:
0d
Set-point temperature
Calculation of number of working hours,
1d
Inlet water temperature (°F)
2d
Outlet water temperature (°F)
3d
Water flow (gallons/min)
4d
Gas type (LP or NG)
5d
Fan speed (Hz)
6d
Burner power (%)
7d
Maximum power (kW)
8d
Back flow temperature (°C)
9d
Not used, setting 00
Working hours
Number in H0
60
60
Number in H1
5
Number in H2
0 (X 10 000) =
(X 100) =
(H0 + H1 + H2) = Total of hours
+
500 +
0 +
560
Table 11
Table 9
36
6 720 644 956
Troubleshooting
10
Troubleshooting
Warning: If you are unable to perform
the tasks listed below, or need
additional assistance please contact
your original installer or licensed gas
technician.
i
Inside the heater it is normal to find
unplugged wire connectors. These
connections are for adding accessories
such as cascading or freeze prevention.
10.1 Introduction
Many of the questions customers ask regarding operation
of this unit can be answered by following the
troubleshooting steps as outlined below. Visit our web site
at www.boschpro.com for more detailed troubleshooting
and service bulletins. For best results, perform each step
before proceeding to the next. The suggested solutions
may require that the cover be taken off. (See Page 7. Fig.
3).
10.2 Burner does not ignite when hot
water is turned ON
1. If the display is blank, verify power to outlet. (120VAC/
60Hz properly grounded circuit required). Verify that
the heater ON/OFF button is turned ON.
2. Verify the fuses in the control board are good. See
Section 7.2, page 25 of the installation manual for fuse
locations.
3. Make sure cold water inlet connection is plumbed to
the right side of heater when facing unit. See Fig. 25,
page 20.
4. A minimum of 0.5 gallons per minute (GPM) (1.9 l/m) is
required to activate the heater. A quart container
should fill in 25 seconds or less to activate heater. In
areas of warm inlet water temperatures, the heater may
increase activation rate to as high as 1.6 gallons per
minute (GPM) to prevent overshooting of set
temperature.
5. Clean inlet filter screen per chapter 9.2, page 32.
6. Inspect the water path for obstructions. Make sure all
showerheads, faucet aerators and whole house filters
are clear of debris.
7. The heater activates when the water flow through the
unit is at or above the required minimum of 0.5 GPM
(1.9 l/m). A crossover in the plumbing creates back
pressure on the water flowing through the heater.
Therefore, a higher flow rate than normal is needed to
force the heater to activate. To check for a plumbing
crossover, shut off the cold water supply to the water
heater. Then open all of the hot water taps served by
the heater. Wait 10 minutes and check for water flow
at taps. There should be no water flowing. Any
continuous flow of water, small or large, indicates a
6 720 644 956
crossover is present and must be corrected. Consult a
professional plumber for help in correcting a crossover.
Failing single lever faucets and mixing valves are
common causes of plumbing crossovers.
8. With the ON/OFF switch turned to OFF (O) position
and the power supply cord unplugged, remove the
unit's front cover (See Page 7. Fig 3). Check wire
connections between the water valve, control unit and
electrode set. See chapter 15.2, page 49 for location
of these parts.
9. Water heater in solar mode. If inlet water temperatures
exceed the water heater's set temperature, the burners
will not ignite and the solar mode indicator will show on
the display. See Fig. 42, page 26.
10.3 Water is too hot
1. Selected temperature on the unit is set too high. To
lower output temperature, see chapter 8.4, page 27.
2. Clean inlet filter screen per chapter 9.1, page 31.
3. Inspect the water path for obstructions. Make sure all
showerheads, faucet aerators and whole house filters
are clear of debris.
4. Confirm the heater's gas type coincides with the type
of gas being supplied. See Fig. 2, page 6 for location
of rating plate.
5. Avoid restrictive outlets. Clean all showerheads and
faucet aerators. It may be necessary to upgrade to
higher flow rate shower heads if allowable by local
code.
6. In areas where the water has a high mineral content,
periodic descaling may necessary. See chapter 9.3,
page 32 for directions.
7. Ensure the outlet temperature sensor is making contact
and firmly mounted on the hot water pipe.
10.4 Water is not hot enough
1. Selected temperature on the unit is too low. To raise
output temperature, see chapter 8.4, page 27.
2. Clean inlet filter screen. See chapter 9.1, page 31.
3. Inspect the water path for obstructions. Make sure all
showerheads, faucet aerators and whole house filters
are clear of debris.
4. Confirm the heater's gas type coincides with the type of
gas being supplied. See Fig. 2, page 6 for location of
rating plate.
5. Check inlet gas particle screen for blockage at gas inlet
connection on bottom of unit.
6. Verify gas pressure is in accordance with specifications
in chapter 6.6, page 24. A gas pressure reading is
needed to proceed further. Contact your original
installer or a local certified gas technician to obtain this
reading.
7. Cold water is mixing into the hot water lines (plumbing
crossover). A plumbing crossover can unintentionally
37
Troubleshooting
mix cold water with the hot water leaving the heater. The
end result is a cooler water temperature than desired.
To check for a plumbing crossover, shut off the cold
water supply to the water heater. Then open all of the
hot water taps served by the heater. Wait 10 minutes
and check all taps for water flow. There should be no
water flowing. Any continuous flow of water, small or
large, indicates a crossover and must be corrected.
Consult a professional plumber for help in correcting a
crossover. Failing single lever faucets and mixing valves
are common causes of plumbing crossovers.
8. Ensure the outlet temperature sensor is making contact
and firmly mounted on the hot water pipe.
10.5 Low water flow/pressure
1. Too many hot water applications are being used
simultaneously or too much flow is demanded. The
water heater will effectively support two 2.0-2.5 GPM
shower heads simultaneously or multiple sink
applications. Greater draws will result in a water
pressure drop and reduced flow at taps.
2. Ensure that gas pressure is in accordance with
specifications in chapter 6.6, page 24. A gas pressure
reading is needed to proceed further. Contact your
original installer or a local certified gas technician to
obtain this reading. If gas pressure is inadequate, the
water heater will close its motorized water valve,
reducing the hot water flow rate in an attempt to reach
the selected output temperature.
3. If selected temperature on the unit is set too high for the
demanded flow rate, the water heater will close its
motorized water valve, reducing the hot water flow rate
in an attempt to reach the selected output temperature.
Lowering the selected temperature will allow the
motorized water valve to open up for increased water
flow rate.
4. Clean inlet filter screen per chapter 9.1, page 31.
5. Inspect the water path for obstructions. Make sure all
showerheads, faucet aerators and whole house filters
are clear of debris.
10.6 Hot water temperature fluctuates
or goes cold at tap
1. Hot water is very hot out of the tap, requiring mixing of
cold water in order to attain a useable hot water
temperature. The addition of too much cold water will
overpower the hot water flow from the tankless water
heater.
This slows the flow within the tankless water heater,
decreasing it below activation point, which shuts off the
burners. The end result is nothing but cold water
coming out of the outlet.
Consult www.boschpro.com for a detailed service
bulletin on overcoming temperature fluctuations.
2. Unbalanced pressure in water lines. Any restriction in
the water heater, such as a clogged inlet filter screen,
can result in unequal pressures between the cold and
38
hot water lines. In such cases, when mixing in the higher
pressure cold water at the tap, the lower pressure hot
water can be overpowered. This will shut down the
burners because the hot water flow rate fell below the
minimum flow rate required for activation. Verify inlet
filter screen is clean and clear of debris. See
chapter 9.1, page 31 for inlet filter cleaning
instructions.
3. Heater deactivated by temperature balancing valves. If
the outlet water temperature is set too high, the heater
can produce temperatures that are too hot. A
temperature balance shower valve will automatically mix
in cold water to reduce the hot water temperature. In the
event of any temperature instability at a fixture using a
temperature balancing valve, refer to the valve
manufacturer for instructions on internal adjustment
setting. An adjustment should be made to minimize the
amount of cold water the valve is adding. Additionally,
the temperature setting on the heater can be lowered to
prevent the temperature balance valve from mixing in
too much cold water.
4. Inlet water pressure is erratic due to fluctuating supply
water pressure. For installation on a private well system
with the use of a pressure tank, the lowest pressure
range setting recommended is 40-60 psi (2.75 - 4.15
bar). Consult your installer or local plumber for effective
ways to maintain constant water pressure to the water
heater when on a well system.
10.7 Noisy burner/heater during
operation
1. Sealed combustion leak. Make sure combustion cover
is securely fastened. Ensure the outdoor cap is properly
sealed with supplied gasket. Leaky seals create
improper combustion resulting in noise.
2. Blocked venting. Ensure exhaust gases are properly
discharging to the outdoors via the louvered openings
on the outdoor cap and/or recess box.
3. Lack of adequate combustion air. Lack of combustion
air will result in unstable burner flames and noise.
Ensure adequate combustion air is provided to the unit
in accordance with specifications in Section 5.1, page
14, Combustion Air Requirements.
4. Lack of adequate gas pressure. Inadequate gas
pressure will cause the fuel-to-air mixture (CO2) to be
out of adjustment. This will result in unstable burner
flames and noise. Ensure gas pressure is in accordance
with specifications in section 6.6, page 24 Measuring
Gas Pressure. A gas pressure reading is needed to
proceed further. Contact your original installer or a local
certified gas technician to obtain this reading.
5. Verify proper CO2 readings per chapter 9.4, page 33.
CO2 adjustments must be done by a certified gas
technician with a calibrated combustion gas analyzer.
6 720 644 956
Problem solving
11
Problem solving
11.1 Error code diagnostics
i
To remove error code from the
display, press the reset button.
Display
Cause
Solution
Fault in the flue gas limiter.
Temperature
above
230°F
(110°C) inside the cabinet.
1. Check continuity of the flue gas limiter (see Fig. 65, page 47).
Go to steps two and three to determine air box temperature
sensor fault and replace it.
2. Check for flue gas leakage around the top and bottom seals of
heat exchanger use mirror to check around the rear as well as the
viewing window.
3. Check that flue gas limiter connector and spade connections
are secure.
4. Unplug heater and check the wiring harness connections inside
the control board.
Appliance selection on “P7” mode
is not correct.
1. Check “P7” mode: the water heater requires setting “NC”.
2. Check jumper and connection on sensor at upper right hand
corner of heat exchanger.
3. Measure jumper resistance, must be 115-125 ohms.
Backflow temperature sensor
defect - happens if sensor is
disconnected or short circuit.
1. Check blackflow temperature sensor connection. See Fig. 65,
page 47.
2. Replace backflow temperature sensor.
3. Check sensor (ref. page 45, chapter 13).
Outlet temperature sensor fault
(Temperature below 36°F or above
210°F).
1. Check red wire connections at hot water temperature sensor.
Clean terminals with an eraser. If badly corroded, replace sensor
and wire harness. See Fig. 65, page 47.
2. Sensor may trip if water temperature drops below 36°F to
protect heater from freezing conditions. Any damage due to
freezing conditions is not covered under warranty.
3. In areas where water has a high mineral content, periodic
descaling may be necessary.
4. Check sensor (ref. page 44, chapter 13).
Table 12
* By installer or service technician only.
6 720 644 956
39
Problem solving
Display
(Flashing)
(Flashing)
Cause
Solution
Outlet temperature sensor not
sensing
expected
output
temperature.
(Status message, not an error).
1. Check that the sensor is firmly attached to the hot water pipe
(see Fig. 71, page 53).
2. Ensure that outlet temperature sensor is not placed on any
bends in the hot water pipe or misreading may occur.
3. Check gas pressure. Low gas pressure may prevent the heater
from reaching desired output temperature.
4. Check supply voltage. It must be 120VAC and properly
grounded.
5. Possible defective control unit call Bosch Water Heating for
further instructions.
Primary fan rotation too low on
operation.
1. Disconnect power supply cord and check wire connection on
back side of primary fan and the connectors on the control board
(see Fig. 72, page 54).
2. Check supply voltage. It must be 120VAC and properly
grounded.
3. Check vent openings. A blockage may cause this failure.
4. Check gas pressure. Low gas pressure may cause the fan to
change its speed to meet desired temperature.
5. Possible defective control unit call Bosch Water Heating for
further instructions.
No rotational speed sensor signal
from primary fan.
1. Disconnect power supply cord and check wire connections on
back side of primary fan and the two connectors on the control
board (see Fig. 72, page 54).
2. Check supply voltage. It must be 120VAC and properly
grounded.
3. Possible defective component in fan or defective control unit
call Bosch Water Heating for further instructions.
Water flow signal over specified
maximum value.
Water flow > 10 gallon/min.
(Status message, not an error).
1. Disconnect power supply cord and check wire connections on
water valve and the two connectors on the control board (see
Fig. 72, page 54).
2. Excessive water pressure and flow. Ensure water pressure is
less than 150psi and flow rate is below 10 gallons per minute.
Over-temperature detected by
outlet temperature sensor on hot
water pipe.
Temperature > 185°F
1. Check that the sensor is firmly attached to the vertical section of
the hot water pipe (see Fig. 71, page 53).
2. Check red wire connections at outlet temperature sensor.
Clean terminals with an eraser. If badly corroded, replace sensor
and wire harness.
3. In areas where water has a high mineral content, periodic
descaling may be necessary. See chapter 9.3, page 32 for
directions.
4. Check sensor (ref. page 44, chapter 13).
Table 12
* By installer or service technician only.
40
6 720 644 956
Problem solving
Display
Cause
Solution
Cold water temperature sensor
fault.
1. Check connector on wires coming from top of watervalve for a
secure connection. See Fig. 65, page 47.
2. Sensor may trip if water temperature drops below 36°F to
protect heater from freezing conditions Any damage due to
freezing conditions is not covered under warranty.
3. Check sensor (ref. page 44, chapter 13).
Backflow temperature sensor over
309°F.
The appliance will close the burner
and lock.
1. Check combustion air and exhaust vent piping for blockage.
2. Check if secondary fan connections are disconnected.
3. Check vent openings. A blockage may cause this failure.
4. Call Bosch Water Heating for further instruction.
Overheat sensor (ECO) open
circuit (resets when cooler
temperatures are detected 220 °F/
104 °C).
1. Disconnect power supply cord and check wire connections on
overheat sensor (top right of heat exchanger) and the two
connectors on the control board. See Fig. 65, page 47.
2. Check white wire connections at overheat sensor. Clean
terminals with an eraser. If badly corroded, replace sensor and
wire harness.
3. Check vent openings. A blockage may cause this failure.
4. In areas where water has a high mineral content, periodic
descaling may necessary, see chapter 9.3.
5. Unplug power supply cord to the water heater. Open a hot
water tap for several minutes to allow cold water to pass through
heat exchanger. Close hot water tap and disconnect lead wires to
overheat sensor. Using a multimeter, check continuity through
overheat sensor contacts. Replace sensor if open.
No flame ionization detected with
water flow.
1. Verify that all manual gas shut off valves are open.
2. Check gas type, see Fig. 2, page 6.
3. Reset error code and open a water tap to cycle the heater in an
effort to purge air on new installations. Cycling hot water tap on
and off multiple times may be necessary. If heater still faults with
EA error code, have a licensed gas technician properly purge air
out of the gas line leading to the water heater.
4. Check three wire connections to ignition group on the lower
front of the heat exchanger are secure.
5. Check gas pressure, see chapter 6.6, page 24.
6. Check vent openings for blockage. Improper venting may cause
premature failure of the flame sensor rod.
7. Check that the minimum power fan speed has been adjusted to
the proper value. See page 29.
8. Observe inside the viewing window of the heat exchanger when
a hot water tap is opened. Sparking should be followed by a
steady blue flame. If flame is unstable or yellow with proper gas
pressure, confirm CO2 readings per section 9.4.
Table 12
* By installer or service technician only.
6 720 644 956
41
Problem solving
Display
Cause
Solution
Ionization failure during operation.
1. Check gas type, see Fig. 2, page 6.
2. Check three wire connections to ignition group on the lower
front of the heat exchanger are secure.
3. Check vent openings for blockage. Improper venting may cause
unstable burner flames and loss of flame ionization.
4. Check that the minimum power fan speed has been adjusted to
the proper value. See page 29.
5. Check gas pressure, see section 6.6, page 24.
6. Check and adjust CO2 readings, see section 9.4, page 33.
Internal hardware/software failure.
1. Disconnect power supply cord and check the two wire and
ground connections on control board as well as ground connection
on heater chassis.
2. Pushing the wrong combination of buttons on the control unit
can create confusion among the microprocessors inside. In this
case, the error code should not happen more than once or twice.
Turn off the water heater. Turn water heater back on and try
resetting error code. Use the reset button (
) to reset any error
codes.
3. Possible defective control unit. Call Bosch Water Heating for
further instructions.
Ionization error at standby.
1. Loose connection to the flame ionization rod. Verify that the
thinner wire leading from the control unit is securely connected to
the flame sensor located on the lower front of the heat exchanger.
See Fig. 65, page 47.
2. Flame ionization rod or control unit may be damaged. Contact
Bosch Water Heating for further instruction.
Gas leakage error, gas valve circuit
not closing properly.
1. Disconnect power supply cord and check wire connections on
gas valve and the two connectors on the control board.
2. Flow water out of a hot water tap above the minimum activation
point of 0.5 GPM. Measure voltage at the gas valve wire plug
connection. The voltage should measure 24VDC between the left
pair of wires and 24VDC between the right pair of wires when the
unit is operating. If voltage is not proper, contact Bosch Water
Heating for further instruction.
3. Gas valve may be defective, contact Bosch Water Heating for
further instrucation.
Table 12
* By installer or service technician only.
42
6 720 644 956
Electrical diagram
12
Electrical diagram
16
20
15
13
M
M
12
M
E
PS
11
10
19
T=104°C
T=220°F
18
9
T=110°C
T=230°F
8
FS
7
6
Casc.
5
input
Casc.
4
output
Back flow
3
2
1
17
16
...
1 20
...
1
21
14
JP2
JP7
JP5
JP8
JP6
22
6720608158-92.1AL
Fig. 60 Electrical scheme
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Intlet water temperature sensor
Outlet water temperature sensor
Backflow temperature sensor
Cascading output connection
Cascading input connection
Ionization sensor
Water flow sensor
Flue gas limiter
Heat exchanger overheat sensor (ECO)
Gas valve
Jumper resistance
Water valve
Primary fan
ON/OFF switch
Secondary fan
AC plug
Main connection
Ignition electrodes
Ground post
Antifreeze kit connection
Fuse
Fuse
6 720 644 956
43
Sensor resistance charts
13
Sensor resistance charts
110
222
2 17
2 12
207
202
19 7
19 2
18 7
18 2
177
172
16 7
16 2
157
152
14 7
14 2
13 7
13 2
12 7
12 2
117
112
10 7
10 2
97
92
87
82
77
72
67
62
57
52
47
42
37
32
10 5
10 0
95
90
85
80
75
70
65
60
55
50
Temp ºC
Temp ºF
Outlet NTC characteristics
45
40
35
30
25
20
15
10
5
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21 22
23
24
25 26
27 28
29
30
31 32
33
34
35 36
37
Resistance (Kohm)
Fig. 61
12 0
247
242
237
232
227
222
2 17
2 12
207
202
19 7
19 2
18 7
18 2
177
172
16 7
16 2
157
152
14 7
14 2
13 7
13 2
12 7
12 2
117
112
10 7
10 2
97
92
87
82
77
72
67
62
57
52
47
42
37
32
115
110
10 5
10 0
95
90
85
80
75
70
65
60
55
50
Temp ºC
Temp ºF
Inlet NTC characteristics
45
40
35
30
25
20
15
10
5
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Resistance (Kohm)
Fig. 62
44
6 720 644 956
Sensor resistance charts
155
302
297
292
287
282
277
272
267
262
257
252
247
242
237
232
227
222
2 17
2 12
207
202
19 7
19 2
18 7
18 2
17 7
17 2
16 7
16 2
15 7
15 2
14 7
14 2
13 7
13 2
12 7
12 2
117
112
10 7
10 2
97
92
87
82
77
72
67
62
57
52
47
42
37
32
150
14 5
14 0
13 5
13 0
12 5
12 0
115
110
10 5
10 0
95
90
85
80
75
70
Temp ºC
Temp ºF
Back Flow characteristics
65
60
55
50
45
40
35
30
25
20
15
10
5
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
Resistance (Kohm)
Fig. 63
6 720 644 956
45
GWH 940 ESO Functional scheme
14
GWH 940 ESO Functional scheme
IDLE
Water flow
> 0.5 gpm
(> 1.9 l/min)
(see WF calc.)
water tap
open?
See error code table
NO
YES
Fan speed = correct
Ionization = off
Temp. limiter = closed
Temp. sensors = ok
Over heat protection = ok
Appliance
ready to start?
YES
Fan speed
OK?
NO
NO
NO
waiting
time of 10s
passed?
YES
YES
Start sparking
Open the gas
valve
INPUTS:
- FANSPEED
- WATER TEMP.
- WATERFLOW
Ionization
detected?
OUTPUTS:
- FANSPEED
- WATERFLOW
NO
NO
NO
1st
Safety time
of 5s passed?
NO
2nd
Safety time of
5s passed?
YES
YES
3rd
Safety time
of 5s passed?
YES
YES
Hot water
delivered at
selected temp.
YES
safety
devices
OK?
See error
code table
NO
YES
water tap
closed
<0.5 gpm?
Post purge of
fan for 7 sec.
NO
YES
close one gas
valve
NO
waiting
time of
1s passed?
flame off?
Stay blocked
till RESET
YES
close second
gas valve
Water flow
Calculus
NO
YES
Post purge of
fan for 7 sec.
WF =
Minimum Power
(Set point - Inlet)
NO
6720608158-65.2V
0.5 GPM < WF < 1.6 GPM
(2 l/min < WF <6 l/min)
NO
WF > 1.6 GPM
(WF > 6 l/min)
YES
YES
Burner ON
Burner ON
Burner shutdown at:
Set point +9°F (5°C)
WF < 0.45 gpm ± 0.05 gpm
(WF < 1.7 l/min ± 0.2 l/min)
Burner shutdown at:
Set point +14°F (8°C)
WF < 0.45 gpm ± 0.05 gpm
(WF < 1.7 l/min ± 0.2 l/min)
Water flow procedure
Fig. 64 Functional scheme
46
6 720 644 956
Interior components diagram and parts list
15
Interior components diagram and parts list
15.1 Interior components
Fig. 65 Components
1
2
3
4
5
6
7
8
9
10
11
Flue gas collector
Heat exchanger
Flame sensor
Primary fan (Mixer)
Outlet temperature sensor
LCD display
On/Off button
Reset button
Program key
Flue gas limiter
Heat exchanger overheat sensor
6 720 644 956
12
13
14
15
16
17
18
19
20
21
Ignition electrodes
Observation window
Backflow temperature sensor
Secondary air fan
Gas valve
Water valve with engine and temperature sensor
Control unit
Up button
Down button
LED
47
Interior components diagram and parts list
Fig. 66 Appliance overview
48
6 720 644 956
Interior components diagram and parts list
15.2 Components diagram
15.2.1 Group 1
12
10
5
6
8
9
7
3
11
4
2
1
6720644956-07.1V
Fig. 67 Components Diagram
Reference
Item
Description
Reference
Front cover
8 705 431 408
10
Combustion cover clip
8 701 201 032
Cover shield
8 705 506 907
11
Grommet set
8 710 203 039
12
Mounting bracket
8 701 309 164
Item
Description
1
2
3
Trade mark badge
8 701 103 140
4
Cover screw
8 703 401 170
5
Combustion cover
8 700 506 300
6
Combustion cover gasket
8 704 701 084
7
Observation window
8 705 600 003
8
Holding bracket
8 708 104 103
9
Screw
8 703 403 012
Table 13
Table 13
6 720 644 956
49
Interior components diagram and parts list
15.2.2 Group 2
3
2
1
5
4
8
9
6
7
6720902974.AA JF
Fig. 68 Components Diagram
Item
Description
Reference
Item
Description
Reference
1
Heat exchanger
8 705 406 422
6
Site window
8 701 000 401
Ignition group
8 701 302 249
2
Heat exchanger top gasket
8 704 701 052
7
3
Flue gas collector
8 705 700 153
8
Heat exchanger O-ring
8 700 205 147
9
Rubber grommet
8 710 303 027
4
Overheat sensor (ECO)
8 707 206 204
5
Heat exchanger bottom gasket
8 704 701 054
Table 14
Table 14
50
6 720 644 956
Interior components diagram and parts list
15.2.3 Group 3
5
1
2
4
3
6
9
16
13
12
8
11
7
15
14
17
6720902975.AA JF
Fig. 69 Components Diagram
Item
Description
Reference
Item
Description
Reference
Gas / Air Mixer
8 705 700 170
8 700 205 149
1
Main burner
8 708 120 699
9
2
Burner gasket
8 704 701 087
10
Air duct O-ring
3
Primary fan
8 707 204 071
11
Venturi
8 700 306 226
4
Backflow temperature sensor
8 707 206 459
12
O-ring
8 700 205 224
5
Washer
8 704 701 097
13
Mixer / Fan gasket
8 704 701 059
Screw
2 910 642 150
8 701 004 049
6
Fan mount nut
2 915 011 006
14
7
Secondary fan - NG
8 707 204 094
15
Plate gasket
7
Secondary fan - LPG
8 707 204 072
16
Air supply duct
8 705 700 155
8
Screw
8 703 403 012
17
Screw
2 910 952 122
Table 15
6 720 644 956
Table 15
51
Interior components diagram and parts list
15.2.4 Group 4
14
11
10
13
12
11
6
7
9
1
8
2
5
3
4
6720608158-73.1AL
Fig. 70 Components Diagram
Item
Description
Reference
Item
Description
Reference
Gas filter
8 700 507 002
1
Gas valve
8 707 021 019
8
2
Pressure tapping
8 703 404 219
9
Gasket
8 704 701 085
3
Washer
8 700 203 041
10
Gas / Fan connector
8 705 202 140
4
Pressure balance tube
8 700 703 136
11
Washer
8 704 701 062
Regulation screw
8 703 404 220
5
Pressure balance nut
8 703 300 041
12
6
Gas supply pipe
8 700 715 389
13
O-ring
8 700 205 009
7
Gas valve washer
8 700 103 014
14
Screw
2 910 149 181
Table 16
52
Table 16
6 720 644 956
Interior components diagram and parts list
15.2.5 Group 5
4
3
12
4
1
5
6
2
8
13
7
11
12
9
10
9
11
15
16
17
14
6720902977.AA JF
Fig. 71 Components Diagram
Item
Description
Reference
Item
Description
Reference
Inlet fitting
8 703 305 348
1
Water valve with engine
8 708 505 024
10
2
O-ring
8 700 205 147
11
O-ring
8 700 205 157
3
Cold water pipe
8 700 715 394
12
Watervalve clip
8 716 102 607
8 701 201 028
13
Water filter
8 700 507 001
Inlet fitting with filter (optional)
8 703 305 356
8 700 103 764
4
Pipe connection clip
5
Hot water pipe
8 700 715 469
14
6
Temperature sensor
8 700 400 015
15
Washer (optional)
7
Outlet fitting
8 703 305 349
16
Water filter (optional)
8 700 507 059
8
Inlet / Outlet washer
8 710 103 045
17
O-ring (optional)
8 700 205 231
9
Wireform spring
8 701 300 025
Table 17
Table 17
6 720 644 956
53
Interior components diagram and parts list
15.2.6 Group 6
4
8
5
6
7
9
10
3
2
11
1
14
15
16
12
13
6720644956-09.1V
Fig. 72 Components Diagram
Item
Description
Reference
Item
Description
Reference
1
Control unit
8 707 207 368
9
Electrode cables
8 704 401 346
1 904 521 342
10
Flue gas limiter
8 700 400 032
Kit intelligent cascading (optional)
7 709 003 962
7 709 003 665
2
Fuse T2.5A
3
Fuse T1.6A
8 700 609 008
11
4
Power supply cables
8 704 401 371
12
Freeze prevention kit (optional)
5
Power supply cord
8 704 401 378
13
Remote control (optional)
TSTAT2
6
Fan cables
8 704 401 347
14
Shaped seal (optional)
8 700 201 012
7
Wire harness
8 704 401 348
15
Screw (optional)
8 703 401 109
8 704 401 376
16
Printed circuit transceiver (optional)
8 708 300 123
8
Table 18
54
Jumper
Table 18
6 720 644 956
Protecting the en vironment
16
Protecting the environment
Packing
The packing box may be fully recycled as confirmed by
the recycling symbol
.
Components
Many parts in the heater can be fully recycled in the end
of the product life. Contact your city authorities for
information about the disposal of recyclable products.
Saving water resources:
B Make sure you close all the taps after any use. Avoid
leaving the taps dripping. Repair any leaking tap.
B Define the temperature you want, in the appliance or
with the remote control. This way you have the
precise water flow needed (mixing cold water to
regulate temperature will increase the water flow with
consequent waste of water).
6 720 644 956
55
Limited Warranty
17
Limited Warranty
General
Service Labor Costs
BOSCH PRO tankless water heaters are warranted by
the
Manufacturer
(BOSCH)
through
Bosch
Thermotechnology Corp.
Bosch Thermotechnology Corp. will furnish a
replacement heat exchanger and will furnish a
replacement of any other part which fails in normal use
and service within the applicable periods specified
below, in accordance with the terms of this warranty.
The Bosch Thermotechnology Corp. replacement will
be warranted for the unexpired portion of the original
warranty. This warranty will be valid only for water
heaters in possession of the original purchaser as
recorded on the warranty card.
This warranty does not cover any labor costs
associated with service, removal or re-installation of
part(s). All such costs must be borne by the Purchaser.
Additionally, this warranty does not cover any labor
costs associated with service, removal, installation or
re-installation of the original water heater or a replaced
water heater.
The Heat Exchanger
How to Make a Claim
If the heat exchanger fails within Fifteen (15) years after
the original installation and operation, Bosch
Thermotechnology Corp. will furnish a replacement
heat exchanger. However, if the water heater is used
within an approved hot water recirculation and supplied
with circulated water, this heat exchanger warranty is
limited to three (3) years from date of original installation
and operation. If the water heater is installed in other
than a single family dwelling, this heat exchanger
warranty is limited to two (2) years from date of original
installation and operation.
Any claim for warranty parts should be made to your
local dealer or distributor:
Exceptions
This warranty will not apply:
• 1. to defects or malfunctions resulting from failure to
properly install, operate or maintain the unit in
accordance with the printed instructions provided;
• 2. to damage or abuse, accident, neglect or freezing
and other acts of nature;
• 3. to damage resulting from operation with either the
flame sensor rod or overheat sensor removed;
• 4. to failure of the heat exchanger resulting from the
operation of the water heater in a corrosive
atmosphere or at water temperatures exceeding the
maximum rating, or if the water heater is not supplied
with potable water;
• 5. to defects or damage cause by any attachment
or modification, including any energy-saving device;
• 6. to damage resulting from scale deposits and/or
highly mineralized / unsoftened water supply.
All Other Parts
If any other part fails within five (5) years after original
installation and operation, Bosch Thermotechnology
Corp. will furnish a replacement part free of charge.
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NOTE: the water heater must be free of
damaging scale deposits and not subject
to gas pressures greater than those
shown on the rating plate, which must not
be altered, defaced or removed.
BOSCH THERMOTECHNOLOGY CORP.
50 Wentworth Avenue
Londonderry, NH 03053
Tel. 866-330-2730
www.boschpro.com
In most cases, the dealer or distributor will be able to
promptly honor your claim and subsequently notify
Bosch Thermotechnology Corp.. However, all
replacements are made subject to validation by Bosch
Thermotechnology Corp. of in-warranty coverage. The
damaged or defective item must be made available in
exchange for the replacement.
Miscellaneous
No one is authorized to make any other warranties on
behalf of Bosch Thermotechnology Corp.. It is
expressly understood that the replacement warranty of
Bosch Thermotechnology Corp. shall be in lieu of any
and all other warranties, express or implied, including
warranties of merchantability or fitness for a particular
use or purpose, and further that Bosch
Thermotechnology Corp. shall not be liable for any loss
or damage directly or indirectly arising from the use of
the hot water heater, or for any consequential damages
arising from such use (including damages from water
leakage). Bosch Thermotechnology Corp. sole liability
with respect to any defect shall be for the replacement
of the defective part(s). Some states do not allow such
limitations and exclusions, so the above may not apply
to you.
This warranty gives specific legal rights. You may also
have other rights which vary from state to state.
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Limited Warranty
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Installer Checklist to be completed by installer upon installation
Serial Number
___ ___ ___ ___ ___ ___ ___ ___
(8 digit serial number is located on rating plate on right side panel)
Gas Pressure Reading*
Static__________
Operating__________
Building Water Pressure
__________
Range if on Well system __________
Installing Company
_____________________________________________
Installer name
_____________________________________________
Address
_____________________________________________
Phone
_____________________________________________
* See Chapter 6.6, page 24 and gas pressure table (to be filled out by installer)
Installation manual should be left with the owner after the installation is tested and completed
Replacement Parts available from:
BOSCH THERMOTECHNOLOGY
CORP.
50 Wentworth Avenue
Londonderry, NH 03053
Tel. 866-330-2730
www.boschpro.com
Bosch Termotecnologia SA
Estrada de Cacia
3800 - 533 Cacia - PORTUGAL
© 2010 Bosch Thermotechnology Corp.,
Londonderry, NH