C 950 ES
INDOOR MODEL
Temperature Modulated with Electronic Ignition
Suitable for heating potable water and space heating
(Intended for variable flow applications)
C 950 ES - Natural Gas
C 950 ES - Liquefied Petroleum (LP) Gas
6 720 646 812 (2011/05) 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 minimum
installation clearances
5
5
5
6
8
3
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
3.10
3.11
3.12
3.13
3.14
Installation instructions
Specialized tools
Introduction
Venting
Combustion air requirements
Proper location for installing your heater
Heater placement and clearances
Mounting installation
Gas piping & connections
Water connections
Water quality
Filling the condensate trap
Domestic hot water recirculation
Space heating applications
Measuring gas pressure
10
10
10
10
24
25
25
25
26
29
29
31
32
33
35
Electrical connections
Electrical power supply
Position of the fuses in control unit
36
36
36
5
5.1
5.2
Operation instructions
Description LCD Display
For your safety read before operating
your water heater
Power
Temperature selection
Use of optional remote control accessory
(part no. TSTAT2)
Operation
Reset button
Program button
Locked condition
37
37
5.6
5.7
5.8
5.9
Maintenance and service
Annual maintenance
Winterizing for seasonal use
Mineral scale build-up
Condensing heat exchanger unit
Adjusting CO2
Program values
Control board diagnostics
41
41
41
42
42
43
45
46
7
7.1
7.2
47
47
7.3
7.4
7.5
7.6
7.7
Troubleshooting
Introduction
Burner does not ignite when hot
water is turned ON
Water is too hot
Water is not hot enough
Low water flow/pressure
Hot water temperature fluctuates at tap
Noisy burner/heater during operation
47
47
47
48
48
48
8
8.1
Problem solving
Error code diagnostics
49
49
9
Electrical diagram
53
10
Sensor resistance charts
54
11
Functional scheme
56
9
4
4.1
4.2
5.3
5.4
5.5
6
6.1
6.2
6.3
6.4
6.5
6.6
6.7
38
38
38
39
39
39
40
40
12
Interior components diagram
and parts list
12.1 Interior components
12.2 Components diagram
57
57
59
13
Protecting the environment
66
14
LIFETIME LIMITED WARRANTY
FOR BOSCH PRO TANKLESS
WATER HEATERS
67
Notes
69
15
2
6 720 646 812
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 combustion
air supply and flue pipe installation 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 using approved vent material
See table 2, page 10 (For Canada use
only ULCS636 approved material).
Vent and combustion air connector
piping must be sealed gas-tight to
prevent possibility of flue gas spillage,
carbon monoxide emissions and risk of
fire, resulting in severe personal injury
or death. Approved vent terminators
must be used when penetrating to the
outside.
Warning: Place the heater in a location
where water leaks will do NO DAMAGE
to adjacent areas or lower floors.
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.
6 720 646 812
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 or to lower floors of the
structure. 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: Keeping 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.
3
Warning
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.
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
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 such
as those used for boiler treatment, shall
not be introduced into the potable water
used for space heating.
HOT
BURN
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.
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
6 720 646 812
Appliance details
2
Appliance details
2.1
Features
Parts
• Key Pad interface control
• High power pre-mix compact burner with low NOx
emissions
i
2.2
BOSCH is constantly improving its
products, therefore specifications are
subject to change without prior notice.
Specifications (Technical data)
Approved in US/Canada
Capacity
• Modulating Gas Valve with constant gas:air ratio
control
Maximum flow rate: 7.15 GPM (27 l/min) at a 45°F
(25°C) rise.
• Modulating water valve for improved comfort and
temperature control.
Maximum output
157,700 Btu/h (46.2 kW)
High quality materials for long working life
• Copper heat exchanger
• High efficiency Ceramat Burner
Maximum input
175,000 Btu/h (51.2 kW)
• Compact space saver: mounts on a wall with a
supplied bracket.
Efficiency in %
Features
Minimum Input
• Easily removable one-piece cover
19,900 Btu/h (5.8 kW)
• On/Off and Temperature control switches
• Reset button
• Program button (Selectable temperature default)
Thermal efficiency > 92%
Temperature Control
Selection range: 100°F (38°C) - 140°F (60°C)
Default temperature: 122°F (50°C)
• Failure codes for easy diagnostics and repair
Stability: +/- 2°F (+/- 1°C)
• Real-time diagnostics for troubleshooting/informational purposes
Gas Requirement
• Built in freeze prevention.
Note: 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.
Gas connection (inches) - ¾”
Inlet gas pressure under operation (with a high hot
water flow rate)*
• Propane: 8” - 13” water column
• Natural Gas: 3.5” - 10.5” water column.
* To measure Gas Pressure, see Measuring Gas
Pressure, chapter 3.14, page 35.
Water
Accessories (Bosch part #)
• Hot water connection (inches) - ¾”
• Optional wireless remote control to operate with the
appliance (TSTAT2)
• Cold water connection (inches) - ¾”
• Cascading kit (77090003962)
• Outdoor kit (BTOK)
• External water filter (part # 8 703 305 356)
• Concentric termination kit (196016)
• 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).
• Exhaust/Intake bird screen (L2594)
• Minimum recommended water pressure: 30 PSI
(2.07 bar)
• Condensate drain tee (196061) [included with Concentric termination kit]
• Minimum well pressure 40 psi, see page 29.
• Pipe Cover (PTPCES)
• High temperature kit (7736500074)
• Recess box kit (7736500043)
• Pressure relief valve (FWL-2).
6 720 646 812
• Connections:
– Bottom of heater
Combustion
• NOx ≤ 14 Ng/J (Nanograms of NOx (calculated as NO2) per
Joule of heat output).
5
Appliance details
• CO ≤ 290 ppm (measured)
2.3
• CO2 level set from factory, see chapter 6.5, page 43.
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.
Dimensions
• Depth (in): 11¼” (286 mm)
• Width (in): 17 7/8” (452 mm)
Unpacking the heater
• Height (in): 30½” (775 mm)
• Weight: 74 pounds (33.5 kg).
Gas types
Natural Gas.
LP Gas.
Voltage
120 V AC (60 Hz) nominal
Amperage
Idle - 40 mA
Operation - ≤ 2.5 A
Fig. 2
Noise
A
B
Rating plate
Serial number
Type of gas
45 - 65 db (A)
The box includes:
Safety devices
• C 950 ES
• Flame failure device (ionization flame rod sensor)
• Bracket for wall hanging the heater
• Overheat prevention (temperature limiter)
• Exhaust vent adaptor (with 4 screws and gasket
provided)
• Inlet temperature sensor
• Outlet temperature sensor
• Back flow temperature sensor
• Combustion air inlet adaptor (with 3 screws and gasket provided)
• Exhaust gas temperature sensor.
• Installation manual (manual can be downloaded at
www.bosch-climate.us)
Water protection
• Product registration card
IP X4 (protection against water drops)
• Energy Guide label.
i
If appliance is installed at elevations above
2000ft, refer to Section 3.3.7 Fan speed
adjustment.
Please complete and return the enclosed product
registration card.
The C 950 ES 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 21).
• Outdoor installation without installation of
Outdoor kit (BTOK).
• Applications where inlet water temperature is
higher than 140 °F (60°C). A 3-way valve or
mixing valve must be installed before the
appliance if inlet water temperature exceeds
this limit.
6
6 720 646 812
Appliance details
To remove front cover
B Loosen the two Phillips head screws located on
bottom rear of cover (see Fig. 3).
6720644956-11.1V
Fig. 3
Loosen the two screws
Fig. 5
Remove the combustion cover
B Lift front cover panel upward and remove.
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).
6 720 646 812
7
Appliance details
2.4
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 CSA
B149.(1,2) INSTALLATION CODES and /or local
installation codes.
B 2. Carefully plan where you install the heater. Correct
combustion air supply and vent pipe installation are
very important. If not installed correctly, fatal
accidents can occur, such as carbon monoxide
poisoning or fire.
B 3. When the unit is installed indoors and ROOM
SEALED (twin pipe) it is permitted to be located in
bathrooms, bedrooms and occupied rooms that are
normally kept closed. See chapter 3.3 (page 10). If
the unit will be installed indoors and use indoor
combustion air, the place where you install the heater
must have enough ventilation. The National Fuel
Gas Codes do not allow UNSEALED gas fired
water heater installations in bathrooms,
bedrooms or any occupied rooms normally
kept closed. See chapter 3.4 (page 24).
B 4. You must correctly vent your heater. See
chapter 3.3 (page 10) on VENTING.
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 3.8 (page 26).
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.
8
6 720 646 812
Appliance details
Dimensions and minimum installation clearances
6
2.5
4
6720608000-03.2AL
Fig. 6
1
2
3
4
5
6
7
Dimensions
On/Off button
Reset button
Program key
Power ON or stand-by LED
LCD display
Up button
Down button
Model C 950 ES
TOP (A)
12”
FRONT (B)
1”
BACK
0”
SIDES
1”
FLOOR (C)
12”
Table 1 Minimum clearances
Fig. 7
Minimum clearances
Note: For servicing access, a 2ft clearance is
recommended to the front cover.
6 720 646 812
9
Installation instructions
3
Installation instructions
3.1
Specialized tools
Warning: In areas where outside
temperatures routinely come close to
freezing, sealed combustion operation
is required. Concentric termination or
separate terminations for combustion
and vent, must be installed on the same
wall or roof surface; however, never
facing the direction of prevailing winds.
Failure to do so may result in heat
exchanger freezing and bursting. This
failure is not covered under the
manufacturer's warranty.
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:
Warning: Protect the exhaust and inlet
from leaves and debris by installing a
screen on the end of the terminator.
¼" mesh minimum opening
recommended on screen.
B Damage or injury.
B Improper operation.
B Loss of warranty.
Warning: The water heater must be
installed by a qualified installer in
accordance with these instructions. If
improperly installed, a hazardous condition
such as explosion or carbon monoxide
poisoning
could
result.
Bosch
Thermotechnology
Corp.
is
not
responsible for improperly installed
appliances.
i
3.3
Common installation practice is to
first
determine
the
venting/
combustion air point of termination,
then design the piping layout back to
the heater.
Venting
3.3.1
All combustion air and vent pipe materials and fittings
must comply with the following:
Item
Vent or
air pipe
and
fitting
or
B Do not common vent with any other
vented appliance or stove.
B Do not use Type-B vent as the actual
exhaust vent system for the appliance.
Warning: Failure to vent the exhaust
gases to the outside (see Table 2 for
proper material) may result in
dangerous flue gases filling the
structure in which it is installed.
10
Material
United States
PVC schedule 40
ANSI/ASTM D1785
PVC-DWV
ANSI/ASTM D2665
CPVC schedule 40
ANSI/ASTM F441
ABS-DWV schedule 40 ANSI/ASTM D2661
PVC
Pipe
cement / CPVC
primer
ABS
Canada
CSA or ULC
certified only
(ULC-S636)
ANSI/ASTM D2564
ANSI/ASTM F493
ANSI/ASTM D2235
Table 2 Approved vent material
For specific questions concerning vent material,
specifications, usage or installation, please
contact the vent manufacturer directly.
Warning:
B Do not reduce the exhaust
combustion air vent pipe sizes.
Vent material
i
Do not use cellular foam core pipe.
All vent connections must be glued, except for the
exhaust accessory (see section 3.3.4) which is
screwed into place on the top of the appliance. Slide
the vent pipe into the exhaust accessory. The exhaust
pipe must be properly supported and must be pitched
a minimum of a ¼ inch per foot back to the appliance.
This allows the condensate to drain properly.
An optional concentric vent/air intake termination can
be used for the installation of a vertical or horizontal
venting system. (see Fig. 8).
The concentric vent/air intake body can be ordered
from your local wholesaler. (Part# 196016).
The appliance can also be installed with separate air
intake and exhaust piping (see Fig. 11, Fig. 18 and Fig.
19, page 18).
6 720 646 812
Installation instructions
Description
Kit part no.
and quantity
Length
Venting specifications
Diam.
Aproved terminals
196016
3- In. Rain Cap
4- In. Diameter SDR-26
Pipe
N/A
1
24 In. long
1
3- In. Y
Concentric Fitting
N/A
1
37-1/8 in.
long
1
3- In. Condensate drain
Tee
N/A
1
3 or 4 inches
PVC Flue Cap*
(ECAP321)
Vertical terminations only
3" diameter only
Concentric
“T” terminal
N/A
I
n
t
a
k
e
1
Table 3 Concentric vent part breakdown
MAINTAIN 12 IN. (18 IN. FOR CANADA)
MINIMUM CLEARANCE ABOVE
HIGHEST ANTICIPATED SNOW LEVEL.
MAXIMUM OF 24 IN. ABOVE ROOF.
90° elbow
(196016)
2- ½ In. Diameter SDR26 Pipe
1.5- In. Condensate drain
bushing
“T” terminal
E
x
h
a
u
s
t
90° elbow
3 or 4 inches
PVC Flue Cap*
(ECAP321)
Vertical & horizontal terminations approved
3" diameter only
Concentric
(196016)
EXHAUST
Table 4 Venting specifications for intake and exhaust
COMBUSTION
AIR
ROOF BOOT/
FLASHING (FIELD
SUPPLIED
CONCENTRIC
VENT KIT
(196016)
*
ULC S636-95, UL1738 certified
Condensate drain requirements
An external condensate drain (not supplied with the
heater) must be installed under the following
conditions:
• All vertical terminating vent installations.
• Horizontal terminating vent installations where the
total linear vent length is greater than 6 feet (1.8 m).
INTAKE
EXHAUST
3" (76mm)
3" (76mm)
DRAIN TEE
(196278)
• Vent installations where any section of the exhaust
vent pipe passes through an unconditioned space.
Minimum combustion air and exhaust pipe
length
The minimum exhaust pipe length is 1 foot (0.3m) of
straight vent pipe. The minimum combustion air pipe
length is one 90° elbow.
6720608836-27.2V
Fig. 8
Concentric vent kit example
3.3.2
Vent specifications
Establish vent clearances that comply with the vent
manufacturer's specifications and all applicable
national/local codes.
6 720 646 812
11
Installation instructions
Maximum combustion air and exhaust pipe
length
Use of elbows
The following tables display the maximum allowable
straight pipe lengths for combustion air and exhaust
piping with consideration to the number of elbows
used. Reduce the equivalent length for each elbow
used from the maximum allowable length depending on
the system used. Refer to table 5 if using 3" diameter
venting. Refer to table 6 if using 4" diameter venting.
3"
Venting
Maximum
allowable
Exhaust
pipe length
Maximum
allowable
Combustion
air pipe
length
Elbow
Equivalency
90°
45°
Twin pipe
system
31ft
31ft
5 ft
3 ft
Concentric system
23ft
23ft
5 ft
3 ft
Table 5 Maximum Allowable Exhaust and Combustion
Air Lengths for 3" venting
4"
Venting
Maximum
allowable
Exhaust
pipe length
Maximum
allowable
Combustion
air pipe
length
It is recommended to limit the amount of elbows used in
the exhaust and combustion air piping to reduce friction
in the air flow. The following lists the maximum amount
of 90° elbows allowed in either the exhaust or combustion air piping:
Max. number of 90°
elbows
3"
venting
4"
venting
Twin pipe system
5
7
Concentric system
4
7
Table 7
i
Two 45° elbows are equal to one 90°
elbow. Any combination of 45° and
90° elbows may be used in the vent
system as long as the combination
does not exceed the maximum listed
in table 7 above.
Elbow
Equivalency
90°
45°
Twin pipe
system
63ft
63ft
2.5ft
1.5ft
Concentric system
43ft
43ft
2.5ft
1.5ft
Table 6 Maximum Allowable Exhaust and Combustion
Air Lengths for 4" venting
12
6 720 646 812
Installation instructions
Calculation example for 3" venting:
Calculation example for 4" venting:
Exhaust
Exhaust
System used
Concentric
System used
Twin pipe
Number of 90° elbows needed:
1
Number of 90° elbows needed:
1
Number of 45° elbows needed:
2
Number of 45° elbows needed:
2
Table 8
Table 12
Calculation of example
Calculation of example
Max. length
23’
Max. length
90° elbow reduction
- 5’
90° elbow reduction
sub-total =
45° elbow reduction
18’
- 6’
Total =
- 2.5’
sub-total =
45° elbow reduction
61.5’
- 3’
12’
Table 9
i
63’
Total =
58.5’
Table 13
For this example, the maximum allowable
exhaust pipe length is 12 feet.
Combustion air
i
For this example, the maximum allowable
exhaust pipe length is 58.5 feet.
Combustion air
System used
Concentric
System used
Twin pipe
Number of 90° elbows needed:
2
Number of 90° elbows needed:
2
Number of 45° elbows needed:
1
Number of 45° elbows needed:
2
Table 10
Table 14
Calculation of example
Calculation of example
Max. length
23’
Max. length
63’
90° elbow reduction
- 10’
90° elbow reduction
- 5’
sub-total =
45° elbow reduction
13’
- 3’
Total =
45° elbow reduction
10’
Table 11
i
sub-total =
58’
- 3’
Total =
55’
Table 15
For this example, the maximum allowable
combustion air pipe length is 10 feet.
6 720 646 812
i
For this example, the maximum allowable
combustion air pipe length is 55 feet.
13
Installation instructions
Required direct vent terminal clearances (twin pipe / concentric penetration)
6720608836-23.1Av
Fig. 9
Canadian installations1)
U.S. installations2)
A
Clearance above grade, veranda, porch, deck or balcony
12 in.
12 in.
B
Clearance to window or door that may be opened
36 in.
12 in.
C
Clearance to permanently closed window
*
*
D
Vertical clearance to ventilated soffit located above the vent
terminator within a horizontal distance of 2 feet (61cm) from the
center line of the terminator
*
*
E
Clearance to unventilated soffit
*
*
F
Clearance to outside corner
*
*
G
Clearance to inside corner
*
*
H
Clearance to each side of center line extended above meter/
regulator assembly
36 in. within a height 15 feet above
meter/ regulator assembly
*
I
Clearance to service regulator vent outlet
36 in.
*
J
Clearance to non-mechanical air supply inlet to building or the
combustion air inlet to any other application
36 in.
12 in.
K
Clearance to mechanical air supply inlet
72 in.
36 in. above if within 10 feet
horizontally
L
Clearance above paved sidewalk or paved driveway located on
public property
84 in. 3)
*
M
Clearance under veranda, porch deck or balcony
12 in. 4)
*
Table 16
1)
2)
In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code
In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code
3)
4)
A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.
Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the floor.
*
For clearances not specified in ANSI Z223.1 / NFPA 54 or CSA-B149.1, one of the following shall be indicated:
a) A minimum clearance value determined by testing in accordance with section 2.20, or;
b) A reference to the following footnote:
“Clearance in accordance with local installation codes and the requirements of the gas supplier.”
14
6 720 646 812
Installation instructions
Required other than direct vent terminal clearances (single pipe penetration)
6720608836-23.1Av
Fig. 10
Canadian installations1)
U.S. installations2)
A
Clearance above grade, veranda, porch, deck or balcony
12 in.
12 in.
B
Clearance to window or door that may be opened
36 in.
4 feet below or to side of opening;
1 foot above opening
C
Clearance to permanently closed window
*
*
D
Vertical clearance to ventilated soffit located above the vent
terminator within a horizontal distance of 2 feet (61cm) from the
center line of the terminator
*
*
E
Clearance to unventilated soffit
*
*
F
Clearance to outside corner
*
*
G
Clearance to inside corner
*
*
H
Clearance to each side of center line extended above meter/
regulator assembly
36 in. within a height 15 feet above
meter/ regulator assembly
*
I
Clearance to service regulator vent outlet
36 in.
*
J
Clearance to non-mechanical air supply inlet to building or the
combustion air inlet to any other application
36 in.
4 feet below or to side of opening;
1 foot above opening
K
Clearance to mechanical air supply inlet
72 in.
36 in. above if within 10 feet
horizontally
L
Clearance above paved sidewalk or paved driveway located on
public property
84 in. 3)
84 in.
M
Clearance under veranda, porch deck or balcony
12 in. 4)
*
Table 17
1)
2)
In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code
In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code
3)
4)
A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.
Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the floor.
*
For clearances not specified in ANSI Z223.1 / NFPA 54 or CSA-B149.1, one of the following shall be indicated:
a) A minimum clearance value determined by testing in accordance with section 2.20, or;
b) A reference to the following footnote:
“Clearance in accordance with local installation codes and the requirements of the gas supplier.”
6 720 646 812
15
Installation instructions
3.3.3
Vent configuration examples
MINIMUM
1”
Below are approved examples of vertical and horizontal
venting installations.
MAINTAIN 12 IN. (18 IN. FOR CANADA)
MINIMUM CLEARANCE ABOVE
HIGHEST ANTICIPATED SNOW LEVEL.
MAXIMUM OF 24 IN. ABOVE ROOF.
3" (80mm)
3" (80mm)
INTAKE
EXHAUST
EXHAUST
DRAIN TEE
COMBUSTION
AIR
EXHAUST
3" (80mm)
INTAKE
6720608643-11.2V
DRAIN TEE
Fig. 13 Horizontal venting system (concentric vent)
6720608836-24.2V
Fig. 11 Vertical venting system (single pipe penetration)
4"
Fig. 14 Horizontal parallel venting system (twin pipe
direct vent)
HORIZONTAL RUN
DOWN TO
TERMINATOR.
NOTE:
MINIMUM 1FT OF
STRAIGHT VENT PIPE
REQUIRED
6720608836-25.1Av
SIDE
OF
WATER
HEATER
6720608542-10.1V
Fig. 12 Horizontal venting installation (combustion air
piping not shown)
Warning: Single pipe penetration should be used in
non-freezing climates only!
16
6 720 646 812
Installation instructions
3" (80mm)
EXHAUST
INTAKE
4” Min.
DRAIN TEE
Fig. 16 Exhaust connection
6720608643-12.2V
B Attach the combustion air inlet accessory to the top
of the unit Fig. 17 (position 2) using the 3 screws and
gasket provided, and install 3" air intake pipe over the
accessory.
Fig. 15 Horizontal venting system (single pipe penetration)
*Warning: Single pipe penetration should be
used in non-freezing climates only!
3.3.4
Vent connections
Attaching the exhaust and air inlet connection
adaptors to the top of the heater
B Attach the flue gas exhaust accessory to the top of
the unit Fig. 16 (position 1) using the 4 screws and
gasket provided, and fully insert vent pipe into the
accessory. If using 4" venting, a 3" to 4" increaser
should be installed directly after this accessory.
i
NOTE: Vent pipe must be completely
vertical when inserting or blue gasket
inside exhaust accessory can become
displaced. Exhaust accessory can be
removed with vent pipe attached to check
gasket position.
Fig. 17 Inlet connection
i
3.3.5
NOTE: The combustion air accessory can
be installed on the top right or on the top
left side of the heater. The combustion air
inlet that is not used must be kept sealed.
Connecting the condensate water drain
Warning:
B Failure to properly install condensate
drain can damage the appliance and will
void the warranty.
Warning:
B Do not install condensate drain tubing in
areas where it may freeze.
6 720 646 812
17
Installation instructions
i
i
The condensate must be disposed of in
accordance with local codes.
See chapter 3.11 “Filling the condensate
trap”.
Use materials approved by the authority
having jurisdiction. In the absence of other
authority, PVC, and CPVC pipe must
comply with ASTM D1785, F441 or
D2665. Cement and primer must comply
with ASTM D2564 or F493. For Canada,
use CSA or ULC certified PVC or CPVC
pipe, fittings and cement, see table 2.
External condensate drain installation
If an external condensate drain (installer supplied) must
be installed (Section 3.3.2), the following is
recommended:
• 1. Install condensate drain on a horizontal section of
the exhaust pipe as close to the heater as possible.
• 2. The condensate must be disposed of according to
local codes.
• 3. To install condensate drain in vent system, use
PVC 3" X 3" X 1.5" tee (part# 196278) and reduce
for drain connection.
Appliance condensate drain installation
The appliance comes equipped with an internal
condensate drain and siphon. This drains condensation
formed in the secondary heat exchanger. Piping must
be installed under the condensate drain outlet on the
water heater and piped for disposal in accordance with
local codes.
4” Min.
Condensate drain
Dispose of condensate in
accordance with local codes
6720608643-17.2V
Leave min. ¼" air gap
1 ½" x ½" PVC Reducer
Trap required
Fig. 18 Appliance drain installation
Fig. 19 External condensate drain installation
3.3.6
Freeze prevention
In cold climates, components of a tankless water heater
can freeze and burst from negative draft. A leading
cause of negative draft is combustion appliances in the
building not being supplied with sufficient combustion
air. A wood stove or furnace can pull its combustion air
from the water heater‘s vent pipe, allowing the cold
incoming air to freeze the cold water in the heat
exchanger. Supplying more combustion air for all combustion appliances is the solution. A HVAC specialist
should be consulted to design solutions for providing
more combustion air.
Listed below is an additional measure designed to further limit backdraft in extreme conditions assuming all
other possible causes have been addressed.
18
6 720 646 812
Installation instructions
Backdraft reducer
The Heat Fab backdraft reducer (9301BFP) is the preferred option for limiting backdraft (see Fig. 20).
Note: The following solution is available only for
3" diameter venting.
6720608643-18.1V
Fig. 20 Part nr 9301BFP
6720608542-06.2V
Fig. 22
Installation
For this solution to be effective, the internal flapper must
be 100% closed when the water heater is not running.
Refer to Figures 22 and 23 for preferred installation
positions in the vent system.
Preferred damper position for vertical terminations
Installation considerations:
• Install damper per the supplied manufacturer‘s
instructions.
Unconditioned
space. Do not
install damper.
• The damper is only to be used in the exhaust vent
piping.
• Ensure directional arrow on damper label faces in the
same direction as exhaust flow.
Enclosed vent
pipe. Do not
install damper.
• If installed horizontally, the axis must be horizontal or
slightly pitched up towards termination to ensure
damper closes 100% when heater is not running.
• To allow accessibility, damper must not be installed
in an enclosed section of vent pipe.
• Do not install damper in unconditioned spaces (e.g.
attics) Condensation can build up while the heater is
running which can later freeze and potentially block
the flapper.
6720608836-30.2V
6720608643-19.1V
Fig. 21 Blackflow reducer (9301BFP) installed
6 720 646 812
Fig. 23
19
Installation instructions
3.3.7
Fan speed adjustment
! IMPORTANT INFORMATION:
Natural gas heaters with installation altitudes
below 2,000 ft above sea level disregard this
section.
Installation adjustment:
After installing the tankless water heater, the fan speed
values for minimum power (P2) and maximum power
(P1) may need adjustment due to variations in altitude
and vent pipe length. Failure to make necessary
adjustments to fan speed values may result in improper
operation of the appliance.
First calculate the total equivalent vent length. This is
the straight pipe length of both exhaust and combustion
air plus the number of elbows used. To determine the
length equivalency of each elbow refer to tables 5 and
6.
Use the equivalent vent length value to determine the
appropriate fan speed values found in table 18 and 19.
Refer to page 22 on how to adjust the fan speeds if an
adjustment is necessary. After changing fan speed values, proceed to section 6.5 to confirm CO2 values are
within specified ranges.
20
6 720 646 812
Installation instructions
Natural
Gas
Altitude
(above sea
level)
0 - 2000 ft
(0 - 610 m)
Liquid
propane
Maximum Maximum
Vent
Total equivalent Minimum power power fan power fan
terminal vent length1)
fan speed (P2) speed (P1) speed (P1)
Concentric
Twin
system
2000 - 4500 ft Concentric
(610 - 1372 m)
Twin
system
4500 - 8000 ft Concentric
(1372 - 2439 m)
Twin
system
6 - 25 ft
13
26 - 46 ft
13
6 - 37 ft
13
38 - 62 ft
13
No
modification
required
No
modification
required
6 - 25 ft
14*
47*
47*
26 - 46 ft
14*
48*
48*
6 - 37 ft
13*
47*
47*
38 - 62 ft
14*
48*
48*
6 - 25 ft
14*
48*
48*
26 - 46 ft
16*
48*
48*
6 - 37 ft
14*
48*
48*
38 - 62 ft
15*
48*
48*
For operation at elevations above 2,000 ft
(610 m) the equipment ratings shall be
reduced at the rate of
4% for each 1,000 ft
(305 m) above sea
level
* Above 2000 ft, CO2 levels must be checked with a combustion gas analyzer, see section 6.5 for instructions.
Table 18 Fan speed adjustment for 3" piping
1)
Full equivalent length (inlet + outlet piping + fittings)
Natural
Gas
Altitude
(above sea
level)
Maximum Maximum
Vent
Total equivalent Minimum power power fan power fan
terminal vent length1)
fan speed (P2) speed (P1) speed (P1)
Concentric
0 - 2000 ft
(0 - 610 m)
Twin
system
Concentric
2000 - 4500 ft
(610 - 1372 m)
Twin
system
Concentric
4500 - 8000 ft
(1372 - 2439 m)
Liquid
propane
Twin
system
3.5 - 39 ft
13
40 - 86 ft
13
3.5 - 59 ft
13
60 - 126 ft
13
3.5 - 39 ft
No
modification
required
No
modification
required
14*
47*
47*
40 - 86 ft
14*
48*
48*
3.5 - 59 ft
13*
47*
47*
60 - 126 ft
14*
48*
48*
3.5 - 39 ft
14*
48*
48*
40 - 86 ft
16*
48*
48*
3.5 - 59 ft
14*
48*
48*
60 - 126 ft
15*
48*
48*
For operation at elevations above 2,000 ft
(610 m) the equipment ratings shall be
reduced at the rate of
4% for each 1,000 ft
(305 m) above sea
level
* Above 2000 ft, CO2 levels must be checked with a combustion gas analyzer, see section 6.5 for instructions.
Table 19
1)
Fan speed adjustment for 4" piping
Full equivalent length (inlet + outlet piping + fittings)
6 720 646 812
21
Installation instructions
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 and press
ON/OFF button
to turn appliance ON.
B Press and hold "Program" button
and press
ON/OFF button to turn appliance ON.
Fig. 24
Fig. 25
B As soon as '188' is displayed, release "Program"
button
, and the display reads P2.
B As soon as '188' is displayed, release "Program" button
, and the display reads P2.
B Press the minus button
to display P1.
B Press
to enter P2 adjustment. The current setting will appear on the display (factory default: 12).
B Press “Program” button
to enter P1 adjustment.
The current setting will appear on the display.
B Press
or
to choose the fan speed suitable
with your installation, see table 18 and table 19.
B Press
or
to choose the fan speed suitable
with your installation, see table 18 and table 19.
B Press and hold (± 5 sec.) “Program” button
until
the display flashes, then the selected value is
memorized.
B Press and hold (± 5 sec.) “Program” button
until
the display flashes, then the selected value is memorized.
i
22
Proceed directly to Section 6.5 to confirm
CO2 values are within range.
i
Proceed directly to Section 6.5 to confirm
CO2 values are within range.
6 720 646 812
Installation instructions
Attention residents of the Commonwealth of Massachusetts:
In the Commonwealth of Massachusetts the following
regulation went into effect on 12/30/2005:
signage installed in accordance with the provisions of
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:
(b)EXEMPTIONS: The following equipment is exempt
from 248 CMR 5.08(2)(a)1 through 4:
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.
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".
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
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.
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
6 720 646 812
23
Installation instructions
3.4
Combustion air requirements
Warning: In areas where outside
temperatures routinely come close to
freezing, sealed combustion operation
is required. Use a concentric
termination or separate terminations for
combustion and vent, which must be
installed on the same wall or roof
surface, however never facing the
direction of prevailing winds. Failure to
do so may result in heat exchanger
freezing up and bursting. This failure is
not covered under the manufacturer's
warranty.
Warning: When installed in an
environment where corrosive chemicals
or dirty air (e.g. hair salons, car washes)
are present the twin pipe system is
required.
Twin pipe and Concentric pipe
The water heater is designed as a sealed combustion
appliance. It is recommended that the combustion air
be provided by a dedicated 3” or 4” pipe from the
outside (twin pipe) or by connecting to the Concentric
vent kit (see Fig. 8). The combustion air pipe may be
PVC or any other rigid sealed 3" or 4" pipe. The
combustion air piping must pitch down 1/4 inch per
foot towards termination to prevent rain water from
entering the appliance. In twin pipe penetrations, the
combustion air inlet, whether terminating vertically or
horizontally, must be located in such a manner as
to provide a minimum 3 foot clearance from the
exhaust vent terminator. See Fig. 9 and 10 Letter I,
page 14.
For the maximum length of the combustion air
pipe, see Tables 5 & 6.
Warning: Terminations must prevent
rain and debris from entering the
combustion air and exhaust vent piping.
below for providing adequate combustion air for the
water heater as well as any other appliances that may
consume air in the same space. Always follow local
codes if they are more stringent and regulations.
• Appliances located in unconfined spaces:
– a) An unconfined space is one whose volume is
greater than 50 cubic feet (1.42 cubic meter) per
1000 Btu per hour (292.81 Watts) of the
combined rating of all appliances installed in the
space. That would be 9950 cubic feet (281.8
cubic meters) for the water heater alone.
– b) In unconfined spaces in buildings of
conventional
frame,
masonry,
or
metal
construction, infiltration air is normally adequate to
provide air for combustion.
• Appliances located in confined spaces:
The confined space must be provided with two permanent openings, one commencing within 12 inches
(304.8mm) of the top and one commencing within
12 inches (304.8mm) of the bottom of the enclosure.
Each opening must have a minimum free area of one
square inch per:
– 1000 Btu/hr (292.81 Watts) if all air is taken from
inside the building
– 2000 Btu/hr (585.62 Watts) if all air is taken from
the outside by horizontal ducts
– 4000 Btu/hr (1171.24 Watts)if all air is taken from
the outside by direct openings or vertical ducts
Or the confined space must be provided with one
permanent opening or duct that is within 12 inches
(304.8mm) of the ceiling of the enclosure. This opening
must have a minimum free area of one square inch per:
– 3000 Btu/hr (878.43 Watts) if all air is taken from
the outside by a direct opening or vertical duct.
Louvers, grills and screens have a blocking effect, when
used, increase the sizes of your openings by 300% for
wood louvers (as wood type will reduce the free air by
75%) and 43% for metal louvers (as metal will reduce
the free air by 30%). Refer to the National Fuel Gas
Code for complete information. In buildings of tight
construction all air should be taken from outside.
Single pipe
Note: This appliance requires 9950 cubic feet of
available combustion air, or a minimum of 1243
square feet of space with an 8 foot ceiling to
operate. If the large amount of air space, which
equates to about half of most average sized
homes, is not available, the appliance must pull
air from the outside (see twin pipe above).
Although it is permissible to draw combustion air from
the inside, it is not the manufacturer’s recommended
installation method. Always install a 3 inch 90° elbow on
the top of the combustion air inlet adaptor to prevent
foreign objects from falling into the unit.
If a single pipe installation is utilized, follow guidelines
24
6 720 646 812
Installation instructions
3.5
Proper location for installing your
heater
Carefully select the location of the water heater. For
your safety and for proper heater operation, you must
provide combustion air to the heater and a proper
exhaust vent system.
Follow the guidelines below:
B 1. Locate the heater where venting, 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 6.2, page 41 “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.
3.6
Warning: Do not install this appliance
on a carpeted wall. The heater must be
mounted on a wall using appropriate
anchoring materials.
Warning: In areas where outside
temperature is routinely below 32°F and
the heater is to be installed on the inside
of an exterior wall, a minimum 2" air gap
or rigid insulation between the heater
back and the wall is recommended.
If wall is sheathed with plaster or drywall, it is recommended that two support boards, either 1”x4” or 1/2"
(minimum) plywood first be attached across a pair of
studs, see Fig. 26, page 26.
B Secure the wall mounting bracket provided with the
heater to a wall surface. The heater must be kept
level on the wall surface, see Fig. 27, page 26.
B Hang the appliance on the bracket, see Fig. 28, page
27.
Heater placement and clearances
The water heater design is approved for
installation on a combustible wall (see chapter 3.7
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 noncombustible materials. See Fig. 7, page 9.
3.7
i
Front cover should be removed (see
instructions on page 7) in order to inspect
components visually.
Studs 16"
(406mm) on
center
Mounting installation
Warning: before mounting appliance:
Fig. 26 Distance between support boards
B Check that there are no loose or
damaged parts inside the appliance
B Confirm that the gas type of the
heater matches the gas supply you
will be connecting the heater, See
Fig. 2, page 6.
6 720 646 812
25
Installation instructions
3.8
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 CGA 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.
6720608158-64.1AL
Fig. 27 Leveling wall mounting bracket
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.
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. 31 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. 2.
6720608158-05.1AL
Fig. 28 Mounting the heater
Warning: Appliance must be installed
vertically.
26
6 720 646 812
Installation instructions
Minimum
3”
Gas supply
Cap
Fig. 29 Gas connection
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.
Inlet gas particle screen
(included)
Gas piping
Fig. 30
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 LINE SIZING
The gas supply piping for a single heater should be
sized for a maximum draw of 175,000 BTUH. Measure
the length of gas supply line from the building's gas
main to the heater and use the tables in Fig. 31, page
28 or the gas line manufacturer’s sizing tables to
determine the pipe diameter necessary. If there are
more gas drawing appliances on the line, size the gas
line according to the total maximum amount of BTU
draw input rating of for all appliances combined.
Note: Undersizing the gas line may result in diminished
hot water flow rate and temperature. See chapter 3.14,
page 35 for the procedure to measure gas pressure.
Proper gas pressure must be confirmed at time of
installation.
6 720 646 812
27
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 C 950 ES (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
1650
1450 1270 1150 1050
990
930
870
780
710
650
610
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.
Nominal
Length of Flexible Corrugated Stainless Steel Tubing (CSST), Feet
Tube
size
inches
Black Iron Pipe
iron
Lenght of Pipe, Feet
pipe
10
inches
1/2
20
30
40
50
60
80
291 200 160 137 122 110
94
100
125
84
74
150
67
EHD*
10
20
30
40
50
60
58
1/2
18 EHD 129
91
74
64
58
53
200
3/4
608 418 336 287 255 231 197
175
155
140
120
3/4
23 EHD 254
183
151
131
118
107
1
1145 787 632 541 480 434 372
330
292
265
227
1
30 EHD 521
365
297
256
227
207
Maximum
Capacity
of
Semi-Rigid
(flexible,
non
corrugated) Tubing in Thousands of BTU per Hour of
Undiluted Liquefied Petroleum Gases (at 11 inches
Water Column Inlet Pressure).
Copper
Length of Tubing, Feet
Outside
diameter
Inch
10
20
30
40
50
60
70
80
90 100
3/8
39
26
21
19
_
_
_
_
_
_
(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. 31
28
6 720 646 812
Installation instructions
3.9
Water connections
Warning: This heater is not approved
for preheated water applications
exceeding 140°F (60°C).
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 will 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.
34).
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 - 4.15bar).
3.10 Water quality
HOT
COLD
Fig. 32
Water quality can have an impact on appliance
longevity and may void 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
Max. Levels
pH
TDS (total Dissolved Solids) mg/l or ppm
Fig. 33 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.
6 720 646 812
6.5 - 8.5
500
Total hardness
mg/l or ppm
100 (6
grains)
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
Table 20
29
Installation instructions
Connecting the pressure relief valve (PRV)
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. 34. 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.
Pressure
relief
valve
Fig. 34 Plumbing Connections (with shutoff valves)
and Pressure Relief Valve
30
6 720 646 812
Installation instructions
3.11 Filling the condensate trap
The condensate trap can be filled before or after
connecting the vent pipe.
B Fill the condensate trap by pouring approx.14 oz.
(400ml) of water into the top of the drain tube. To
avoid damage to the appliance use a funnel in this
operation, see Fig. 37, page 31.
Filling the condensate trap before vent pipe
installation
Danger: Prior to initial start up, and
after appliance has been out of use for a
long time or after cleaning the sifon,
make sure that you fill the condensate
trap with water. This is to prevent
dangerous exhaust gases from entering
the building.
B Fill the condensate trap by pouring approx.14 oz.
(400ml) of water into the exhaust accessory on the
top of the appliance, see Fig. 35.
Fig. 37 Filling the condensate trap after installation
B Loosen the three screws of the control unit.
Fig. 35 Filling the condensate trap at start up
Filling the condensate trap after vent pipe
installation
After appliance has been out of use for a long time or
after cleaning siphon, refill the condensate trap with
water.
Please proceed as follows:
Fig. 38
B Put the control unit in service position by engaging its
tabs with the holes in the bottom horizontal sheet
metal, see Fig. 39.
B Check water level in the condensate trap.
B Remove front cover, see Fig. 4, page 7.
B Open the four clips and remove the combustion
cover, see Fig. 5, page 7.
B Remove the clip and disconnect the drain tube, see
Fig. 36.
Fig. 39 Water level in condensate trap
B After filling reassemble all parts in reverse order.
Fig. 36 Disconnect drain tube
6 720 646 812
31
Installation instructions
3.12 Domestic hot water recirculation
Although recirculation directly through the tankless
water heater is allowed, temperature stability is
improved by recirculating through a mini-tank as shown
in Fig. 40. By using the design in Fig. 40, 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.
C 950
ES
5
2
4
1
3
6720608158-77.1AL
Ariston Minitank
Fig. 40 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 after 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.
32
6 720 646 812
Installation instructions
3.13 Space heating applications
Warning: If the set point temperature is
above 120°F, precautions should be
taken to protect users of potable water
from scalding.
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 is
recommended 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.
Warning: Ensure the primary pump is
properly sized to provide adequate flow
for the system heat load.
i
For Pump sizing please refer to the
pressure drop curves, Fig. 41. Also
remember to account for system piping
pressure loss. A minimum of 1.7 GPM is
recommended to provide adequate flow
through the water heater when
determining the size of the primary pump.
Bosch tankless water heaters are approved for use in
combination DHW and space heating applications
(open-loop setup). These water heaters are not
approved for use in space heating only applications
(closed-loop setup). Bosch supports applications of
combination DHW and space heating in an open loop
configuration if plumbed similar to Fig. 42. 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.
Fig. 41 Pressure drop curve
6 720 646 812
33
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. 42 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
34
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
6 720 646 812
Installation instructions
3.14 Measuring gas pressure
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 3.8, page 26.
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 test
port (see Fig. 44).
B Loosen screw inside left test point fitting (do not
remove) and connect manometer tube to test point.
Static Pressure Test
B Turn gas supply back on.
B Record static gas pressure reading in table 22.
P1 fan speed:
Factory default: NG: 46, 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 21). After upgrading gas line, reset
appliance to P1 factory default setting (NG: 46, LP: 46)
or setting from Section 3.3.7.
Operating Pressure Test
B Press ON/OFF button
to turn off the appliance.
B Press and hold "Program"
button and press
ON/OFF button
to turn appliance ON.
Fig. 44 Gas pressure test port (left tapping)
Static Gas Pressure Reading (see Chapter 3.14)
Fig. 43
B As soon as '188' is displayed, release "Program"
button
, and the display reads P2.
B Press
or
enter here: ___________________ Date: ___________
Operating Gas Pressure Reading (see Chapter 3.14)
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 22
For inlet gas pressure adjustment consider the following table:
Gas type
NG
LPG
pin
3.5” WC
8” WC
Table 21Minimum inlet gas pressure under full operation
B Operate all other gas appliances (except heater) on
same gas piping system at maximum output.
B Turn on high volume of hot water flow (at least 6
gpm) and burner will light. If heater display reverts to
P2, open more hot water fixtures to allow sufficient
flow. Press
until P1 reappears on the display.
B Record lowest operating gas pressure reading in
table 22.
6 720 646 812
35
Electrical connections
4
Electrical connections
4.1
Electrical power supply
4.2
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 must 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 9, Fig. 72).
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 from the control unit.
Fig. 46
B Remove the six screws from the back cover of the
control unit, see Fig. 47, pos. 2.
B Check the fuses in the printed circuit board, see Fig.
47, pos. 3.
1
6720608643-15.1AL
1
Fig. 45 Connecting power supply cord
1
2
Power cord length: 3ft.
Note: Outlet appliance is plugged in to should be
clear from possible water damage.
3
6720608158-78.1AL
Fig. 47 Fuses position
B After checking the fuses, reinstall all parts in reverse
order.
36
6 720 646 812
Operation instructions
5
Operation instructions
Fig. 48
1
2
3
4
5
6
7
5.1
On/Off button
Reset button
Program Key
LCD display
Up button
Down button
Power On or stand-by LED
Description LCD Display
Warning: Do not use any cleaning
agressive or corrosive agents to clean
the window.
Fig. 52 Locked condition indicator (only with remote
control)
Fig. 53 Flame indicator
Fig. 49 Power bar indicator (input)
Fig. 50 Temperature indicator
Fig. 51 Error indicator
6 720 646 812
Fig. 54 Solar mode indicator (see chapter 5.4, page
38)
Fig. 55 Remote control indicator
37
Operation instructions
5.2
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.
5.4
Temperature selection
To select hot 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.
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. 57
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.
B. 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.
C. 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.
5.3
Power
On
B To start the appliance press the On/Off button.
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.
Note: The water heater, running at minimum BTU, may
still achieve temperatures above the desired set
temperature. Low flowing fixtures are the leading cause
of this type of temperature overshoot. To combat this
symptom, clean fixtures or replace with higher flowing
ones if necessary.
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)
Fig. 56
Off
B To shut down the appliance press the On/Off button
again.
38
6 720 646 812
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. 54, page 37.
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. 84, component 16) is required when
installing the remote control with this heater.
i
5.6
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 indication
.
DANGER
Fig. 60
B LCD flashes until selected temperature is reached.
B Power bar indicates power percentage in use.
HOT
5.7
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.
Reset button
If the LCD shows the error symbol
do not shut off
power or unplug the heater. Follow instructions below
to reset error first.
Record the error code on LCD and consult “Problem
solving” section 8.1, page 49.
See instruction manual before
setting temperature at water
heater.
Feel water before bathing or
showering.
6720608643-16.1AL
Fig. 58
5.5
Use of optional remote control
accessory (part no. TSTAT2)
Fig. 61
After
following
instructions
“Troubleshooting” section,
indicated
in
B press reset button firmly in order to return heater to
normal operation.
Fig. 59 Remote control
The wireless remote control accessory (Fig. 84,
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
6 720 646 812
Fig. 62 Reset button
If the problem persists, contact your installer.
39
Operation instructions
5.8
Program button
Fig. 63 “Program” key
5.8.1
Memorizing selected temperature
B Press buttons
temperature.
or
to select desired
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.
5.9
Locked condition
This condition is only valid for appliances with one or
more remote controls installed.
Fig. 64 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 unlock 5 minutes after
closing hot water tap.
40
6 720 646 812
Maintenance and service
6
Maintenance and service
Warning: Always shut off the electrical
power supply, shut off the manual gas
valve and shut off the water valves
whenever servicing.
Caution:
B Check and clean the complete water
heating system once a year.
B Carry out a maintenance overhaul if
necessary. Immediately repair defects to
avoid damage to the system.
Annual maintenance table
Every year
Inlet Water Filter
• Verify the inlet filter screen is clean and undamaged.
The inlet water filter is located between the ¾" cold
water inlet fitting on the right side of the appliance,
and the water valve (See Fig. 33, page 29). Close
installer supplied water shutoff, carefully lift the water
valve, then rotate back. Remove filter, clean and or
replace if damaged.
Descaling
• In areas where the water supply has a high mineral
content, the heat exchanger should be 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 6.3
for detailed instructions on descaling the heat
exchanger.
Fin Coils
1. Inspect venting system
X
2. Inspect combustion chamber
X
3. Inspect burner
X
4. Inspect condensate trap
X
• Inspect heat exchanger fincoil for soot build-up or
blockage. To access fincoil, consult service bulletin
at www.bosch-climate.us. If there is evidence of soot
build-up or blockage, the heat exchanger should be
removed by a professsional and cleaned thoroughly.
5. Inspect water filter
X
Condensate trap
Table 23 Annual maintenance
• Check water level in the condensate trap, see Fig.
35.
6.1
• If appliance is out of service for more than 10 days,
fill as described on page 31.
Annual maintenance
(To remove front cover, see page 7.)
• Check for debris and clean if needed.
Venting System
• Venting system - inspect inside of flue pipe for any
blockage or restriction. Observe burner flames
during heater operation. (front cover must be
removed). Inspect the combustion air inlet pipe for
blockage or debris. Inspect combustion air and
exhaust terminations for blockage or debris.
Combustion Chamber
• Inspect burner observation window (Fig. 77, #14) 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 3.4, page 24,
chapter 3.3, page 10 of this manual to verify exhaust
system and combustion air supply meets
manufacturer's specifications.
Pressure Relief
• Manually open the pressure relief valve to ensure
proper operation.
6 720 646 812
6.2
Winterizing for seasonal use
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 and voids the warranty, 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 and relieve pressure
from the plumbing system. If water continues to flow
after 5 minutes, a crossover of the hot and cold water
pipes is present and must be corrected before
proceeding.
41
Maintenance and service
5. 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.
6. Using an air compressor, blow short bursts of air
(100psi max) through the inlet water connection until
there is no water present coming through the outlet
water connection of the heater.
7. Reconnect water fittings and return heater to service
when danger of freezing has passed.
6.3
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
shutoff valve and flush heat exchanger with clean
water.
15.Shut cold water shutoff valve and reconnect hot
water supply to the water heater.
16. Reconnect electrical supply to unit, open water
shutoff valves, and return the unit to service.
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
A7 and E9 and boiling sounds in the heat exchanger.
A water softener is required if the water hardness
exceeds 6 grains/gal (103 mg/l) calcium carbonate.
Damage to the water heater resulting from hard water/
scale deposits will not be covered under warranty.
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. 65.)
Fig. 65
6.4
Condensing heat exchanger unit
The condensing heat exchanger unit must be checked
once a year by a qualified and trained technician. If
repairs are needed, the repairs should be done by a certified Bosch technician.
6. Using another line (B), connect 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 the 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 a straight white
vinegar solution. If using a commercial descalant,
refer to manufacturer's instructions for proper
dilution ratio.
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).
42
Fig. 66 Condensing heat exchanger unit
Condensing heat exchanger unit maintenance;
B Shut off power. Disconnect power cord.
B Dismantle all inlet, outlet pipes and the condensate
tube from the condensing heat exchanger unit.
6 720 646 812
Maintenance and service
B Remove the condensing heat exchanger unit from
the appliance by pulling it towards you.
B Dismantle all parts for inspection and cleaning.
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.
A. Once Gas Pressure is adequate
B Press ON/OFF button to turn OFF the heater.
B Remove brass flat head screw on the exhaust collar
as seen in Fig. 68.
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.
Fig. 67 Condensing heat exchanger
B Check the condensing heat exchanger for any
obstruction.
B Flush the condensing heat exchanger unit with water.
Fig. 68 Measuring port
B Check all gasket and o-rings for damage and replace
if necessary.
B While holding the Program (P) button, press the ON/
OFF button to turn ON the heater (see Fig. 69). 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.
i
It is important to inspect and propely
replace the gaskets and o-rings.
B Assemble the condensate unit and all other parts in
reverse order of disassembly.
6.5
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 49
“Problem solving”).
Caution: One factor that may affect
CO2 levels is improper gas pressure.
Please see Chapter 3.14 for the
procedure to measure gas pressure
and record your findings below:
Static Gas Pressure:
P1 Operating Pressure:
6 720 646 812
“ WC
“ WC
Fig. 69
B. Measuring CO2 (Combustion cover Installed):
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.
Press + until P1 reappears on the display.
B Record the CO2 reading in P1 below. (Analyzer
reading may take several minutes to stabilize).
B Press the ‘+’ button until P2 appears. Unit will ramp
down to low fire and the water flow should decrease.
B Record the CO2 reading in P2 below.
P1 CO2 Reading:
% CO2
P2 CO2 Reading:
% CO2
43
Maintenance and service
D. Returning to Service:
Note: When making adjustments,
combustion cover is installed.
CO2 range (%)
make
sure
Max. CO level
(measured)
Nat. Gas
max. input
P1
7.2 % - 7.8 %
< 250 ppm
min. input
P2
1.5 % - 1.8 %
< 60 ppm
max. input
P1
8.8 % - 9.4 %
< 250 ppm
min. input
P2
1.9 % - 2.2 %
< 60 ppm
1. Return slotted screw cover to original position.
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
* 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 24 CO2 & CO target numbers
C. Adjusting CO2:
Note: P1 adjustment will change the P2 reading.
Confirm the P1 value BEFORE adjusting the P2
level.
Fig. 70 Adjusting P1 CO2 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. 70.
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.
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:
6720608158-38.1AL
Fig. 71 Adjusting P2 CO2 level
B Remove yellow painted #40 Torx cover from the front
of the gas valve. (Fig. 71) 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.
Note: This screw adjustment is very sensitive and
should be made in small increments. It may take several
minutes for readings to stabilize.
3. Verify both P1 and P2 CO2 readings are within the
ranges specified in table 24. Repeat steps 1 and 2 as
necesssary until CO2 values are within the specified
ranges.
Final Readings
P1 CO2 Reading:
% CO2
P2 CO2 Reading:
% CO2
44
6 720 646 812
Maintenance and service
6.6
Program values
Refer to 6.7 Control board diagnostics (page 35)
regarding how to access these P-modes.
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.
Caution: Misadjusted program
values can lead to appliance
malfunction, errors, and service
calls.
Program
Description
Factory Default
MIN
MAX
Comment
P1
Maximum Power
NG: 46,
LP: 46
21
NG: 48,
LP: 48
see chapter 3.14, page 35
note: reducing P1 values below
maximum will reduce maximum
power of the appliance.
P2
Minimum Power
13
12
20
see chapter 3.3.7, page 20
P3
Remote
Controls installed
_0
_0
6
see chapter 5.5, page 39
P4
Access to
Diagnostic Mode
E
0d
10f
see chapter 6.7, page 46
P5
Cascade Mode
NO
NO
CC
contact Bosch for details
P6
Temperature Unit
°F
°F
°C
P7
Appliance Type
Cd
Cd
NO
P9
Fan Purge
PH
Cascading type
IC
IC
SC
PC
Master/Slave
mode
CS
CS
CM
Table 25
Condensing / Non-condensing
note: incorrect setting will cause
errors.
runs secondary fan and primary
fan when P9 is selected by
depressing the “P” - button
This menu is only available when
cascade mode is selected CC.
Contact Bosch Water Heating
for details.
Program values, factory default settings and ranges.
6 720 646 812
45
Maintenance and service
6.7
Control board diagnostics
1. Press ON/OFF button to turn off the appliance.
2. Press and hold "Program"
button and press
ON/OFF button to turn appliance ON.
3. Release the
button when '188' appears on the
display. The display should read 'P2' when the
program button is released. If not, repeat process.
4. 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.
5. When the display reads 'P4', press and release the
button once again and the display should read
'E'.
6. Use the
and
button on the control board to
cycle through different diagnostic modes available.
7. Once in the selected diagnostic mode of your
choice, press and release the
button to display
the diagnostic information.
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.
8. Once the information is obtained, press the
button again to return to the diagnostic mode menu and
scroll to addition diagnostic information.
9. Press ON/OFF button to turn OFF the appliance and
back ON again to return heater to normal function.
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 26
6.7.1
Working hours
To see how many hours the appliance has worked,
please enter the “Diagnostic menu” (chapter 6.7);
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
Number in H0
______
_______ +
Number in H1
______ (X 100) =
_______ +
Number in H2
______ (X 10 000) =
_______ +
(H0 + H1 + H2) = Total of hours
_________
Table 27
Diagnostic menu
Example:
E
Entry/Exit into sub-modes
0d
Set-point temperature
1d
Inlet water temperature (°F)
Working hours
2d
Outlet water temperature (°F)
Number in H0
60
3d
Water flow (gallons/min)
Number in H1
5
4d
Gas type (LP or NG)
Number in H2
0 (X 10 000) =
5d
Fan speed (Hz)
6d
Burner power (%)
7d
Maximum power (kW)
8d
Back flow temperature (°C)
9d
Exhaust temperature (°C)
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
Calculation of number of working hours,
60
(X 100) =
(H0 + H1 + H2) = Total of hours
+
500 +
0 +
560
Table 28
Table 26
46
6 720 646 812
Troubleshooting
7
Troubleshooting
Warning: If you are unable to perform
the tasks listed below, or need
additional assistance please contact
your original installer or a licensed gas
technician.
7.1
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.
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).
7.2
Burner does not ignite when hot
water is turned ON
It is recommended to use “Control board diagnostics”
page 46, chapter 6.7 as a tool for problem solving.
1. If the display is blank, verify power to outlet. (120VAC/
60Hz properly grounded circuit required). Verify that the
heater power button is pressed ON.
2. Verify the fuses in the control board are good. To
access fuses, the control board must be removed. See
chapter 4.2, page 36.
3. Make sure cold water inlet connection is plumbed to the
right side of heater when facing unit. See Fig. 32, page
29.
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 23 seconds or less, from hot water tap only, to
activate heater.
5. Clean inlet filter screen per chapter 3.9, page 29.
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 hot and cold plumbing
pipes 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 each tap. There should be no
water flowing. Any continuous flow of water, small or
large, indicates a crossover is present and must be
corrected. Consult a professional plumber for help in
correcting a crossover. Failing single lever faucet mixing
valves are common causes of plumbing crossovers.
8. With the power button pressed switch turned to OFF
and the power supply cord unplugged, remove the
unit's front cover (See Page 7. Fig 3). Check wire
6 720 646 812
connections between the water valve, control unit and
electrode set. See chapter 12.2, page 59 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. 54, page 37.
7.3
Water is too hot
1. Selected temperature on the unit is too high. To lower
output temperature, see chapter 5.4, page 38.
2. Clean inlet filter screen per chapter 6.1, page 41 to
increase flow through the heater.
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 6.3,
page 42 for directions.
7. Ensure the temperature sensor is making contact and
firmly mounted on the hot water pipe.
7.4
Water is not hot enough
1. Selected temperature on the unit is too low. To raise
output temperature, see chapter 5.4, page 38.
2. Clean inlet filter screen. See chapter 6.1, page 41 to
increase flow through the heater.
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 3.14, page 35. 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
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
47
Troubleshooting
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 faucet mixing valves are
common causes of plumbing crossovers.
8. Ensure the temperature sensor is making contact and
firmly mounted on the hot water pipe.
7.5
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 3.14, page 35. 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 6.1, page 41.
5. Inspect the water path for obstructions. Make sure all
showerheads, faucet aerators and whole house filters
are clear of debris.
7.6
Hot water temperature fluctuates
at tap
1. Hot water is very hot out of the water heater, requiring
mixing in cold water in order to attain a useable hot
water temperature. The addition of too much cold will
overpower hot water flow from the tankless water
heater.
If this slows the flow through the tankless water heater
below its activation point, it will shut off the burners. The
end result is nothing but cold water coming out of the
outlet. Consult www.bosch-climate.us 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
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
48
chapter 6.1, page 41 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.
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
appliance when on a well system.
7.7
Noisy burner/heater during
operation
1. Sealed combustion leak. Make sure combustion cover
is securely fastened. Ensure the exhaust vent adaptor is
properly sealed with supplied gasket. Leaky seals
create improper combustion resulting in noise.
2. Improper venting. Venting that is unsealed, the wrong
material, too big in diameter or too long in run will result
in unstable burner flames and noise. Ensure venting is in
accordance with specifications in chapter 3.3, page
10.
3. Lack of adequate combustion air. Drawing combustion
air from a room area of inadequate size will result in
unstable burner flames and noise. Improper piping of
combustion air to the outside or insufficient space will
result in unstable burner flames and noise. Ensure
adequate combustion air is provided from the unit in
accordance with specifications in Section 3.4, page
24 Combustion Air Requirements.
4. Cross contamination. Ensure that intake and exhaust
terminations maintain required clearances as stated in
chapter 3.3, page 10. Cross contamination between
intake and exhaust may cause unstable burner flames
and noise.
5. Lack of 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 3.14, page 35 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.
6. Verify proper CO2 readings per chapter 6.5, page 43.
CO2 adjustments must be done by a certified gas
technician with a calibrated combustion gas analyzer.
6 720 646 812
Problem solving
8
Problem solving
8.1
Error code diagnostics
i
To remove error code from the
display, press the reset button.
Display
(Flashing)
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. 77, page 57).
Go to steps two and three to determine flue gas limiter fault and
repair 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 on the
control board.
Exhaust temperature sensor happens if sensor is disconnected
or in short circuit or appliance
selection on “P7” mode is not
correct.
1. Check exhaust temperature sensor connection. See Fig. 77,
#1, page 57.
2. Check sensor (ref. page 54, chapter 10).
3. Check “P7” mode: the water heater requires setting “Cd” for
condensing appliances.
Backflow temperature sensor
defect - happens if sensor is
disconnected or short circuit.
1. Check backflow temperature sensor connection. See Fig. 77,
#1, page 57.
2. Replace exhaust temperature sensor.
3. Check sensor (ref. page 54, chapter 10).
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. 72, page 53.
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 necessary.
4. Check sensor (ref. page 54, chapter 10).
Outlet temperature sensor not
sensing
expected
output
temperature.
(Status message, not an error).
1. Check that the sensor is firmly attached to the vertical section of
the hot water pipe, see Fig. 83, page 64.
2. Ensure that hot water 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.
Table 29
* By installer or service technician only.
6 720 646 812
49
Problem solving
Display
(Flashing)
Cause
Solution
Primary fan rotation too low in
operation.
1. Disconnect power supply cord and check wire connection on
back side of fan and the connectors on the control board, see Fig.
84, page 65.
2. Check supply voltage. It must be 120VAC and properly
grounded.
3. Check venting specifications are met. Long vent lengths,
venting with more than three elbows, blocked vent or combination
venting may cause this failure.
4. Ensure intake and exhaust terminations maintain the required
clearances stated in the manual. Cross contamination between
intake and exhaust may cause the fan to alter its rotational speed.
5. Check gas pressure. Low gas pressure may cause the fan to
change its speed to meet desired temperature.
6. 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 fan and the two connectors on the control board, see
Fig. 84, page 65.
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).
1. Disconnect power supply cord and check wire connections on
water valve and the two connectors on the control board, see Fig.
84, page 65.
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
outlet temperature sensor.
Temperature > 185°F
by
1. Check that the sensor is firmly attached to the horizontal section
of the hot water pipe, see Fig. 83, page 64.
2. Check red wire connections at hot water 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 6.3, page 42 for
directions.
4. Check sensor (ref. page 53, chapter 9).
Cold water temperature sensor
fault.
1. Check connector on wires coming from top of watervalve for a
secure connection. See Fig. 77, page 57.
2. Sensor may trip if water temperature drops below 36°F (2 °C).
Protect heater from freezing conditions as any damage due to
freezing conditions is not covered under warranty.
3. Check sensor (ref. page 54, chapter 10).
Table 29
* By installer or service technician only.
50
6 720 646 812
Problem solving
Display
Cause
Solution
Exhaust temperature sensor - the
appliance will close the burner and
lock if it gets over 194°F; (only
applied for condensing unit).
1. Clean and check heat exchanger.
2. Clean and check condensing heat exchanger.
3. Reduce maximum power (chapter 3.14, page 35).
4. Reduce water temperature.
Backflow temperature sensor over
309°F.
The appliance will close the burner
and lock (non-volatile).
1. Check inlet/outlet vent pipes.
2. Check if secondary fan connections are disconnected.
3. Check if venting specifications are met. Long vent lengths,
venting with more than three elbows, blocked vent or combination
venting may cause this failure. See chapter 3.3, page 10.
4. Call Bosch Water Heating for further instructions.
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
the overheat sensor (Fig. 77, page 57) and the two connectors
on the control board.
2. Check white wire connections at the overheat sensor. Clean
terminals with an eraser. If badly corroded, replace sensor and
wire harness.
3. Check that venting specifications are met. Long vent lengths,
venting with more than three elbows, blocked vent or combination
venting may cause this failure.
4. In areas where water has a high mineral content, periodic
descaling may necessary, see chapter 6.3, page 42.
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. 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 on the lower front of the heat
exchanger are secure.
5. Check gas pressure. See chapter 3.14, page 35.
6. Check venting specifications are met. Improper venting may
cause premature failure of the flame sensor rod. See chapter 3.3,
page 10.
7. Check that the minimum power fan speed has been adjusted to
the proper value. See page 20.
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/yellow with proper gas
pressure, confirm CO2 readings per chapter 6.5, page 43.
Table 29
* By installer or service technician only.
6 720 646 812
51
Problem solving
Display
Cause
Solution
Ionization failure during operation.
1. Check gas type, Fig. 2, page 6.
2. Check three wire connections to ignition group on the lower
front of the heat exchanger are secure.
3. Verify that venting specifications are met. Improper venting may
cause premature failure of the flame sensor rod. See chapter 3.3,
page 10.
4. Check gas pressure. See chapter 3.14, page 35.
5. Check and adjust CO2 readings. See chapter 6.5, page 43.
6. Check that the minimum power fan speed has been adjusted to
the proper value. See page 20.
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. Pressing 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 set of electrodes located on the lower front of the heat
exchanger.
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 29
* By installer or service technician only.
52
6 720 646 812
Electrical diagram
9
Electrical diagram
16
20
15
13
M
M
12
M
E
PS
T=90°C
T=194°F
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
6720608158-01.1AL
Fig. 72 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
Exhaust temperature sensor
Water valve
Primary fan
ON/OFF switch
Secondary fan
AC plug
Main connection
Ignition electrodes
Ground post
Antifreeze kit connection
Fuse
Fuse
6 720 646 812
53
Sensor resistance charts
10
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. 73
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. 74
54
6 720 646 812
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 and Exhaust NTC 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. 75
6 720 646 812
55
Functional scheme
11
Functional scheme
Fig. 76 Functional scheme
56
6 720 646 812
Interior components diagram and parts list
12
Interior components diagram and parts list
12.1 Interior components
Fig. 77 Components
1
2
3
4
5
6
7
8
9
10
11
12
Exhaust temperature sensor
Flue gas collector
Heat exchanger
Ionization sensor
Primary fan (Mixer)
Hot water temperature sensor
LCD display
On/Off button
Reset button
Program key
Flue gas limiter
Heat exchanger overheat sensor (ECO)
6 720 646 812
13
14
15
16
17
18
19
20
21
22
23
Ignition electrodes
Observation window
Backflow temperature sensor
Secondary air fan
Gas valve
Condensate trap
Water valve with flow sensor and cold water temperature
sensor
Control unit
Up button
Down button
LED
57
Interior components diagram and parts list
Fig. 78 Appliance overview
58
6 720 646 812
Interior components diagram and parts list
12.2 Components diagram
12.2.1 Group 1
9
16
9
15
12
9
17
13 15
14
10
5
6
8
9
7
3
2
11
4
1
6720902973.AB JF
Fig. 79 Components Diagram
Reference
Item
Description
Reference
Front cover
8 705 431 412
10
Combustion cover clip
8 701 201 032
Cover shield
8 705 506 906
11
Grommet set
8 710 203 039
8 701 103 140
12
Exhaust accessory
8 705 504 152
Gasket exhaust
8 700 103 710
8 708 006 022
Item
Description
1
2
3
Trade mark badge
4
Cover screw
8 703 401 170
13
5
Combustion cover
8 700 506 300
14
Inlet air cover
6
Combustion cover gasket
8 704 701 084
15
Inlet air gasket
8 700 103 166
7
Observation window
8 705 600 003
16
Inlet air accessory
8 705 504 154
8
Holding bracket
8 708 104 103
17
Mounting bracket
8 701 309 164
9
Screw
8 703 403 012
Table 30
Table 30
6 720 646 812
59
Interior components diagram and parts list
12.2.2 Group 2
15
28
29
28
13
17
12
30
16
21
20
26
31
18
16
22
25
13
17
23
12
24
14
8
19
13
13
28
27
35
10
2
3
34
8 11
11
33
8
1
5
32
4
8
6
9
7
6720902980.AA JF
Fig. 80 Components Diagram
60
6 720 646 812
Interior components diagram and parts list
Item
Description
Reference
1
Heat exchanger (LP Gas)
8 705 406 421
1
2
Heat exchanger (Natural Gas)
Heat exchanger top gasket
8 738 721 270
8 704 701 052
3
Condensing exchanger inlet
8 705 700 159
4
Overheat sensor (ECO)
8 707 206 204
5
Heat exchanger bottom gasket
8 704 701 054
6
Site window
8 701 000 401
7
Ignition group
8 701 302 249
8
Heat exchanger O-ring
8 700 205 147
9
Rubber grommet
8 710 303 027
10
Connecting pipe
8 700 715 403
11
Pipe connection clip
8 701 201 028
12
Condensing exchanger gasket
8 704 701 090
13
Condensing exchanger nut
8 703 301 157
14
Condensing heat exchanger
8 705 700 161
15
Condensing exchanger left side
8 705 700 162
16
Condensing exchanger side gasket
8 704 701 091
17
Allen screw
2 918 060 162
18
Condensing exchanger right side
8 705 700 163
19
Screw
2 910 611 496
20
Fincoil O-ring
8 700 205 226
21
Condensing fincoil
8 700 715 402
22
O-ring
8 700 205 228
23
Condensate drain connector
8 705 506 838
24
Condensate drain connector gasket
8 704 701 092
25
Exhaust temperature sensor
8 707 206 459
26
Washer
8 704 701 097
27
U-bend pipe
8 703 305 352
28
Condensing exchanger clip
8 701 300 023
29
Offset pipe
8 700 715 396
30
Flue gas collector
8 705 506 841
31
Cold water pipe upper
8 700 715 398
32
Siphon
8 705 202 141
33
Condensate drain pipe
8 700 703 177
34
Condensate drain pipe clip
8 716 102 607
35
Condensate drain pipe O-ring
8 704 701 094
Table 31
6 720 646 812
61
Interior components diagram and parts list
12.2.3 Group 3
5
1
2
4
3
6
9
16
13
12
8
11
7
15
14
17
6720902975.AA JF
Fig. 81 Components Diagram
Item
Description
Reference
Item
Description
Reference
1
Main burner (Natural Gas)
8 708 120 642
8
Screw
8 703 403 012
Gas / Air Mixer
8 705 700 170
8 700 306 226
1
2
Main burner (LP Gas)
Burner gasket
8 708 120 699
8 704 701 087
9
11
Venturi
3
Primary fan
8 707 204 071
12
O-ring
8 700 205 224
4
Backflow temperature sensor
8 707 206 459
13
Mixer / Fan gasket
8 704 701 059
5
Washer
8 704 701 097
14
Screw
2 910 642 150
Plate gasket
8 701 004 049
6
Fan mount nut
2 915 011 006
15
7
Secondary fan (LP Gas)
8 707 204 074
16
Air supply duct
8 705 700 155
7
Secondary fan (Natural Gas)
8 707 204 072
17
Screw
2 910 952 122
Table 32
62
Table 32
6 720 646 812
Interior components diagram and parts list
12.2.4 Group 4
14
11
10
13
12
11
6
7
9
1
8
2
5
3
4
6720902976.AA JF
Fig. 82 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 33
6 720 646 812
Table 33
63
Interior components diagram and parts list
12.2.5 Group 5
4
3
12
4
1
5
6
2
8
13
7
11
12
9
10
9
11
15
16
17
14 (optional)
6720902977.AA JF
Fig. 83 Components Diagram
Item
Description
Reference
Item
Description
Reference
10
Inlet fitting
8 703 305 348
1
Water valve with engine and
temperature sensor
8 708 505 024
11
O-ring
8 700 205 157
2
O-ring
8 700 205 147
12
Watervalve clip
8 716 102 607
3
Cold water pipe
8 700 715 394
13
Water filter
8 700 507 001
4
Pipe connection clip
8 701 201 028
14
Inlet fitting with filter (optional)
8 703 305 356
5
Hot water pipe
8 700 715 469
15
Washer (optional)
8 700 103 764
6
Temperature sensor
8 700 400 015
16
Water filter (optional)
8 700 507 059
7
Outlet fitting
8 703 305 349
17
O-ring (optional)
8 700 205 231
8
Inlet / Outlet washer
8 710 103 045
9
Wireform spring
8 701 300 025
Table 34
Table 34
64
6 720 646 812
Interior components diagram and parts list
12.2.6 Group 6
4
5
6
7
9
10
3
2
11
1
14
15
16
12
13
6720608158-75.2V
Fig. 84 Components Diagram
Item
Description
Reference
Item
Description
Reference
1
Control unit
8 707 207 366
10
Flue gas limiter
8 700 400 032
1 904 521 342
11
Kit Inteligent Cascading
7 709 003 962
Anti freeze kit
7 709 003 665
2
Fuse T2.5A
3
Fuse T1.6A
8 700 609 008
12
4
Power supply cables
8 704 401 371
13
Remote control (optional)
TSTAT2
5
Power supply cord
8 704 401 378
14
Shaped seal (optional)
8 700 201 012
6
Fan cables
8 704 401 347
15
Screw (optional)
8 703 401 109
16
Printed circuit transciever (optional)
8 708 300 123
7
Wire harness
8 704 401 348
9
Electrode cables
8 704 401 346
Table 35
Table 35
6 720 646 812
65
Protecting the environment
13
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).
66
6 720 646 812
LIFETIME LIMITED WARRANTY FOR BOSCH PRO TANKLESS WATER HEATERS
14
LIFETIME LIMITED WARRANTY
FOR BOSCH PRO TANKLESS WATER HEATERS
MODELS COVERED
ITEMS NOT COVERED
This limited warranty is provided by Bosch
Thermotechnology Corp. (BTC) and covers model C
950 ES (hereinafter referred to as "Water Heater"). This
warranty is provided as long as the Water Heater
remains in the possession of the original purchaser and
installed at its original place of installation.
This limited warranty does not cover the following circumstances:
WARRANTY COVERAGE
HEAT EXCHANGER -Limited Warranty
BTC warrants that the heat exchanger will remain free
of leaks for Fifteen (15) years from the date of original
installation provided that the heat exchanger is properly
maintained by a qualified heating contractor and the
other conditions of this warranty are met. If during this
time a leak occurs and BTC determines that this leak is
the result of a defect in workmanship or materials, BTC,
will replace the heat exchanger. However, if the Water
Heater is used within an approved hot water recirculation system and supplied with circulated water, the heat
exchanger warranty is limited to three (3) years from the
date of original installation. If the Water Heater is
installed in other than a single family dwelling, the heat
exchanger warranty is limited to five (5) years from date
of original installation.
OTHER WATER HEATER PARTS
If any other part fails with five (5) years after original
installation, BTC will furnish a replacement part fee of
charge.
The Water Heater may be delivered with components
not manufactured by BTC ("Other Components). Other
Components are warranted by their manufacturer. BTC
also will warrant the Other Components to be free from
defects in workmanship and material for one year from
the date of installation, provided they are installed and
properly maintained by a qualified heating contractor
and the other conditions of this warranty are met. If a
defect exists in the Other Components, BTC will repair
or replace them, if BTC determines that a defect in
workmanship or materials exists.
SERVICE LABOR COSTS
This warranty provides labor costs, at BTC approved
rates, for one (1) year from the date of original
installation, provided it is installed and properly
maintained by a qualified heating contractor and the
other conditions of this warranty are met.
6 720 646 812
1. Components or parts not provided by BTC.
2. Serviceable items and normal maintenance as
required per the Installation Manual.
3. The workmanship of any installer. BTC disclaims and
does not assume any liability of any nature for unsatisfactory performance caused by improper installation,
repair or maintenance.
4. Any labor or material costs for removal, reinstallation,
repair and replacement of the defective component or
part unless otherwise provided above.
5. Transportation to BTC, if necessary.
6. Damage caused by operation of the Water Heater in
a corrosive atmosphere, scale depots and/or highly mineralized or unsoftened water supply, electrical failures,
flooding, or acts of God.
7. Any Water Heater that has a failure of malfunction
resulting from operation with either the flame sensor rod
or overheat sensor removed.
8. Damage caused by any attachment or modification to
the Water Heater, including any energy-saving device.
9. Damage caused by operation of the Water Heater at
water temperatures exceeding the maximum rating, or if
the water is not supplied with potable water.
10. Shipping charges, delivery expenses or administrative fees incurred by the purchaser in repairing or
replacing the Water Heater.
CONDITIONS OF WARRANTY
The warranty herein is void under the following
circumstances:
1. Failure or malfunction resulting from improper or
negligent operation, accident, abuse, freezing, misuse,
unauthorized alteration or improper installation, repair or
maintenance. See the Owner's Manual for installation
and maintenance information.
2. Any Water Heater that is operated without a flame
sensor rod or overheat sensor.
3. Any Water Heater that is used or operated in a
corrosive atmosphere or at water temperatures
exceeding the maximum rating, or if the Water Heater is
not supplied with potable water.
4. Work performed without prior authorization or
approval and without authorization/requisition number
and without proper documentation verifying compliance
with above terms.
67
LIFETIME LIMITED WARRANTY FOR BOSCH PRO TANKLESS WATER HEATERS
LIMITED WARRANTY
OTHER THAN THE OBLIGATIONS OF BTC
EXPRESSLY SET FORTH HERIN, BTC DISCLAIMS
ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE. BTC'S SOLE OBLIGATION WITH RESPECT TO THE TANK AND PURCHASER'S EXCLUSIVE REMEDIES ARE SET FORTH
IN THE FOREGOING LIMITED WARRANTY. BTC
SHALL NOT BE LIABLE FOR ANY INDIRECT, PUNITIVE, INCIDENTAL, SPECIAL, CONSEQUENTIAL OR
SIMILAR DAMAGES INCLUDING, WITHOUT LIMIITATION, INJURY OR DAMAGE TO PERSONS OR
PROPERTY OR DAMAGES FOR LOSS OF USE,
LOST PROFITS, INCONVENIENCE OR LOSS OF
TIME.
NOTE THAT ANY REPAIRED OR REPLACED PRODUCT WILL BE WARRANTED FOR ONLY THE UNEXPIRED TERM OF THE ORIGINAL WARRANTY.
Some states do not allow the exclusion of limitation of
damages, or limitations on how long an implied warranty
lasts, so the above limitations and exclusions may not
apply to you.
WARRANTY CLAIMS PROCESS
If you have a warranty claim you should notify the heating contractor who installed your Tank and ask that the
contractor notify the distributor from whom the contractor purchased the Tank. If this action is not possible or
you don't receive a response, contact Bosch Thermotechnology Corp., 50 Wentworth Avenue, Londonderry,
NH 03053. To process your claim, you will need a copy
of your original invoice or other proof of purchase and
documentation showing the original installation date
and location. The alleged defective components or
parts must be returned to BTC in accordance with BTC
procedure then in force for handling goods returned for
the purpose of inspection to determine cause of failure
(contact BTC if you have questions regarding the return
process). If BTC determines that the returned components and/or parts are defective and that this warranty
applies, BTC will furnish the repaired or replacement
components and/or parts to an authorized BTC distributor who, in turn, will forward the components and/or
parts to the heating contractor who installed your Water
Heater.
68
6 720 646 812
Notes
15
Notes
6 720 646 812
69
Notes
70
6 720 646 812
Notes
6 720 646 812
71
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 3.14, page 35 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 USA
Tel. 866-330-2730
www.bosch-climate.us
Bosch Termotecnologia SA
Estrada de Cacia
3800 - 533 Cacia - PORTUGAL
© 2011 Bosch Thermotechnology Corp.,
Londonderry, NH