MODEL GWH 2700 ES NG and GWH 2700 ES LP -
INDOOR MODEL
Temperature Modulated with Electronic Ignition
Suitable for heating potable water only
Not approved for space heating purposes
(Intended for variable flow applications)
GWH 2700 ES NG - Natural Gas
GWH 2700 ES LP - Liquefied Petroleum (LP) Gas
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
vapor and liquids in the vicinity of this or any other
appliance.
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.
• If you cannot reach your gas supplier, call the fire
department.
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.
• Immediately call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instructions
• Installation and service must be performed by 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.
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Warning
1
Warning
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.
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: The maximum inlet gas
pressure must not exceed the value
specified by the manufacturer and that
the minimum value listed is for the
purposes of input adjustment.
Warning: Exhaust gas must be vented
to outside using stainless steel vent
material suitable for category III vent
systems and temperatures up to 480°F.
Vent 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: 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: Place the heater in a location
where water leaks will do NO DAMAGE
to adjacent areas or lower floors.
Warning: Keeping appliance area clear
and free from combustible materials,
gasoline and other flammable vapors
and liquids.
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: 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.
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.
Caution: Label all wires prior to
disconnection when servicing controls.
Wiring errors can use improper and
dangerous operation.
Verify proper operation after servicing.
Warning: The heater must be
disconnected from the gas supply
piping system during any pressure
testing of that system at test pressures
equal to or more than 0.5 psig.
Warning: In order for the freeze
prevention kit to provide adequate
protection,120V AC must always be
supplied to the water heater.
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Appliance details
2
Appliance details
Warning: The anti freeze 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.
2.1 Features
Parts
• Key Pad interface control
• High power pre-mix compact burner with low NOx
emissions
B The anti freeze kit will not protect
plumbing outside the appliance from
freezing. Precautions should be taken.
• Modulating Gas Valve with constant gas:air ratio
control
B Always drain the water heater if it will be
exposed to long term freezing
conditions. See Section 6.2 Winterizing
for seasonal use.
• Modulating water valve for improved comfort and
temperature control.
High quality materials for long working life
• Copper heat exchanger
• High efficiency Ceramat Burner
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.
• Compact space saver: mounts on a wall with a
supplied bracket.
Features
• Real-time diagnostics for troubleshooting/informational
purposes
• LCD Display with backlight
• On/Off and Temperature control switches
• Reset button
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.
• Program button (Selectable temperature default)
• Failure codes for easy diagnostics and repair
• Easily removable one-piece cover
• Built in freeze prevention.
Note: The freeze prevention 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.
D A N G E R
- The freeze prevention will not protect plumbing outside
the appliance from freezing. Precautions should be taken.
Accessories (Bosch part #)
• Optional wireless remote control accessory to operate
with the appliance (TSTAT2)
HOT
• Cascading kit (TLINK)
• Outdoor kit (AQOK)
BURN
• Gas conversion kit (8719002176)
• Vertical vent kit (ESVVT)
• Horizontal vent kit (AQ3ES1))
Water temperature over 125°F can
cause severe burns instantly or
death from scalds.
• Stainless steel bird screen (L2594)
(fits into a 3” PCV fitting - Intake vent).
Children, disabled and elderly are
at highest risk of being scalded.
BOSCH is constantly improving its
products, therefore specifications are
subject to change without prior notice.
See instruction manual before
setting temperature at water
heater.
i
Feel water before bathing or
showering.
1) AQ3 vent kit is compatible with this appliance but
requires the purchase of an additional 12" piece of
straight pipe to meet minimum vent length requirements.
The aluminum flex piping included with this kit is not per-
missible for use with this appliance.
6720608643-16.1AL
Fig. 1
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Appliance details
Dimensions
2.2 Specifications (Technical data)
Approved in US/Canada
• Depth (in): 11¼” (286 mm)
• Width (in): 17 7/8” (452 mm)
• Height (in): 30½” (775 mm)
• Weight: 67 pounds (30,5 kg).
Capacity
Maximum flow rate: 7.15 GPM (27 l/min) at a 45°F
(25°C) rise.
Gas types
Maximum output
Natural Gas.
LP Gas.
160,500 Btu/h (47.0 kW)
Maximum input
Converting the gas type can only be done by a certified
gas technician with a calibrated CO2 analyzer.
199,000 Btu/h (58.3 kW)
Call Bosch Water Heating through Bosch
thermotechnology corp. for conversion instructions.
Efficiency in %
Thermal efficiency > 82%
Voltage
Min. Input
120 V AC (60 Hz) nominal
19,900 Btu/h (5.8 kW)
Amperage
Temperature Control
Idle - 40 mA
Operation - ≤ 2.5 A
Selection range: 100°F (38°C) - 140°F (60°C)
Default temperature: 122°F (50°C)
Stability: +/- 2°F (+/- 1°C)
Noise
45 - 65 db (A)
Gas Requirement
Safety devices
Gas connection (inches) - ¾”
• Flame failure device (ionization flame rod sensor)
• Pressure relief valve (supplied with heater)
• Over heat prevention (temperature limiter)
• Inlet temperature sensor
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.
• Outlet temperature sensor
* To measure gas pressure, see Measuring Gas
Pressure, chapter 3.12.
• Backflow temperature sensor.
Water protection
Water
IP X4 (protection against water drops)
• Hot water connection (inches) - ¾”
• Cold water connection (inches) - ¾”
If appliance is installed at elevations above
2000ft, refer to section 3.3.6 Fan speed
adjustment.
• Water valve material: Polymer (PPS) (Polypropylene
Sulfid)
i
• Minimum water flow: 0.65 gallon/minute (2,5 l/m).
Note: Activation varies with inlet water temperatures
from 0.65 - 1.6 gallon/minute.
• Minimum recommended water pressure: 30 PSI
(2.07 bar)
•
Minimum recommended well pressure: 40 PSI (2.75
bar), see chapter 3.9.
• Connections:
– Bottom of heater
Combustion
• NOx ≤ 40 Ng/J (Nanograms of NOx (calculated as NO ) per
Joule of heat output).
2
• CO ≤ 250 ppm (measured)
• CO2 level set from factory, see chapter 6.4.
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Appliance details
To remove front cover
2.3 Unpacking the heater
B Loosen the two Philips head screws located on
bottom rear of cover (see Fig. 3).
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.
Fig. 3 Loosen the two screws
B Lift front cover panel upward and remove.
Fig. 2 Rating plate
A
B
Serial number
Type of gas
The box includes:
• GWH 2700 ES
• Pressure relief valve (150 psi / 200,000 Btu rating)
• Bracket for wall hanging the heater
• Exhaust vent adaptor (with 4 screws and gasket
provided)
• Combustion air inlet adaptor (with 3 screws and gas-
ket provided)
• Installation manual (manual can be downloaded at
www.boschhotwater.com)
• Product registration card
• Energy Guide label.
Fig. 4 Removing the front cover
To remove combustion cover (service only)
Please complete and return the enclosed product
registration card.
B Open the four clips and remove the combustion
cover see Fig. 5.
The GWH 2700 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 18)
• Outdoor installation without installation of Outdoor
kit (AQOK)
• Space heating purposes
• Preheated inlet water supply.
Fig. 5 Remove the combustion cover
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Appliance details
B
10. Failure to install heater correctly may lead to
unsafe operation and void the warranty.
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 CGA
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 9). 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 Code does not allow UNSEALED gas fired
water heater installations in bathrooms,
bedrooms or any occupied rooms normally
kept closed. See chapter 3.5
page 20).
(page 21) and 3.4
(
B 4. You must vent your heater. See chapter 3.3 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
Section 3.8, page 17.
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.
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Appliance details
2.5 Dimensions and Minimum installation clearances
16
41 " 5 ¼"
6 ½"
21 16"
11 ¼"
5 ¼"
7
17
8
"
1
2
5
6
+
reset
P
7
3
4
6720608158-04.2AL
Fig. 6 Dimensions
1
2
3
4
5
6
7
On/Off button
Reset button
Program key
Model GWH 2700 ES
TOP (A)
12”
1”
Power ON or stand-by LED
LCD display
Up button
FRONT (B)
BACK
Down button
0”
SIDES
1”
FLOOR (C)
12”
Table 1 Minimum clearances
Fig. 7 Minimum clearances
Note: For servicing access, a 2ft clearance to front
cover is recommended.
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Installation instructions
3
Installation instructions
3.1 Tools required for installation
Warning: Approved terminators must
be used for inlet and exhaust vent sys-
tems to prevent rain from entering the
appliance. Failure to do so may result in
damage to the appliance. This failure is
not covered under the manufacturer’s
warranty.
• Philips head screwdriver
• Flat head screwdriver
• Adjustable wrench
• Level
• Thermometer
• Standard plumbing tools
• Manometer
Caution: The vent system must be
installed by a qualified installer in
accordance with these instructions. If
• Drill
improperly installed,
a
hazardous
• Pipe wrench
condition such as explosion or carbon
monoxide poisoning could result.
Bosch Water Heating will not be
responsible for improperly installed
appliances.
• Adjustable pliers
• Pipe fitting tools
• Hacksaw
• Hole saw.
Warning: In areas where outside
temperatures routinely come close to
freezing, sealed combustion operation
is required. Use 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.
3.2 Introduction
Please follow these instructions. Failure to follow
instructions may result in:
B Damage or injury.
B Improper operation.
B Loss of warranty.
If you are unable to perform the tasks required to install
this heater properly, please contact a locally licensed
plumber or gas technician.
Common installation practice is to deter-
mine the venting/intake system layout and
penetration and then work back to the
heater.
3.3.1 Vent material
i
Establish vent clearances that comply with the vent
manufacturer's specifications. In all cases, follow local
codes. See Table 2.
3.3 Venting
Diam.
Material
Warning: Do not reduce the vent
(exhaust and combustion) pipe sizes
and do not common vent with any other
vented appliance or stove.
Exhaust
Vent
3 or 4 inches Sealed single wall stainless steel
(AL29-4C)
Intake
Vent
3 or 4 inches Sealed PVC or any other rigid pipe
Warning: Failure to vent the exhaust
gases to the outside with sealed
stainless steel vent pipe (AL29-4C)
may result in dangerous flue gases
filling the structure in which it is
installed.
Table 2 Venting Specifications
Warning: Do not mix vent pipe or
from
joining methods
manufacturers.
different
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Installation instructions
Horizontal venting systems only:
3.3.2 Venting Specifications
An optional stainless concentric vent/air intake termina-
tion can be used to provide only one penetration point
through the exterior wall (see Fig. 8, 9 & 10). The con-
centric vent/air intake kit can be ordered from your local
wholesaler. (Part# ESHCK). Note: Vent piping and
terminal used with concentric vent/air intake kit
must be from the same vent pipe manufacturer.
The appliance can also be installed with separate
air intake and exhaust piping (see Fig. 15 ).
Install appliance as close to point of vent termination as
possible. The exhaust piping must vent directly to the
outside of the structure.
Horizontal sections of vent must pitch upward towards
termination ¼" for every foot of horizontal length, to
prevent the pooling of condensate, and be supported at
4 foot intervals with overhead hangers.
Exception: horizontal run between last elbow and
termination must pitch down to termination 1/4" per
foot. Note: For horizontal terminations, venting must
terminate once it penetrates to the outside of the
structure. There must be no sections of vent pipe
exposed to the outdoors other than the termination.
Note: Listed thimbles or collars are necessary where
venting passes through wall and ceiling partitions. If the
vent system passes through combustible areas where
the vent clearance requirements cannot be maintained,
it is permissible to chase straight sections of sea led 3
inch single wall vent through 4 inch (or greater) T ype-B
vent. The distance to combustibles using this chase
technique is 1 inch 1). Note: Type-B vent must never be
used as the actual exhaust vent system for the
appliance, as it is not gas tight and illegal for use with
this appliance. This will create a serious health hazard
and void the warranty.
6720608782-09.1Av
Fig. 8 Concentric kit part # ESHCK
3”
VENTING
Z flex
Protech
Heat Fab
3 or 4"
90° elbow
2SVEEWCF0390
FSELB9003
9314
3”
Horizontal
Terminal
2SVSTB03
FSTB3
FSRC3
9390 TEE
5300CI
6720608782-10.1Av
3” Vertical
Terminal
2SVSRCF03
Fig. 9 Concentric kit vent assembly
Table 3 Terminator Part Numbers
Fittings or Piping
Equivalent
feet
m
12"
45 degree elbow
90 degree elbow
pipe per foot
1.25
2.5
1
0.38
0.76
0.30
Min. 3 Feet
3” stainless steel pipe
Table 4 Friction Loss Equivalent in piping and fittings
For specific questions concerning vent material, speci-
fications, usage or installation, please contact the vent
manufacturer directly.
Company
Z-flex
Contact info
800-654-5600
ProTech Industries
Heat-Fab
800-766-3473
800-772-0739
6720608782-11.1Av
Fig. 10 Concentric kit installation
Table 5 Vent manufacturers
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Installation instructions
# of 90° elbows
Condensate drain requirements
Air intake or
Exhaust
system
An external condensate drain (not supplied with the
heater) must be installed under the following
conditions:
0
1
2
3
4
0
1
2
N/A*
N/A*
23
26
23
20
17
14
11
8
21
18
15
12
9
16
13
10
7
11
8
• All vertical terminating vent installations.
• Horizontal terminating vent installations where the
total linear vent length is greater than 10 feet (3.1 m).
5
• Vent installations where any section of the exhaust
vent pipe passes through an unconditionedspace.
# of 45°
3
20
N/A**
N/A**
elbows
4
5
6
17
4
Twin pipe termination clearances
The minimum clearance between exhaust vent and
combustion air inlet terminations for twin pipe
penetration is 3 feet.
14
6
N/A** N/A**
N/A** N/A**
11
3
Maximum allowable straight pipe length (ft)
Minimum combustion air and exhaust pipe
length
Table 6 Maximum allowable straight pipe length
The minimum exhaust pipe length is 3 feet (1m) of
straight vent pipe. The minimum combustion air pipe
length is one 90° elbow.
*
Not allowed. At least one 90º elbow required.
Not allowed. Minimum of 3 feet (1m) of straight pipe required.
**
Maximum combustion air and exhaust pipe
length
The following table (Table 6) displays the maximum
allowable straight pipe lengths for combustion air and
exhaust piping with consideration to the number of
elbows used.
Note: 90° elbows used for terminations
should not be counted in the exhaust and
combustion air piping.
i
Step 1: Total the number of 90° elbows and 45°
elbows used on the exhaust piping.
Step 2: Use this value in the table to determine the
maximum straight exhaust pipe length
allowed.
Step 3: Total the number of 90° elbows and 45°
elbows used on the combustion air piping.
Step 4: Use this value in the table to determine the
maximum straight combustion air pipe length
allowed.
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Installation instructions
Required direct vent terminal clearances (twin pipe / concentric penetration)
6720608836-23.1Av
Fig. 11
1)
2)
Canadian installations
U.S. installations
A
B
C
D
Clearance above grade, veranda, porch, deck or balcony
Clearance to window or door that may be opened
Clearance to permanently closed window
12 in.
12 in.
36 in.
12 in.
*
*
*
*
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
F
Clearance to unventilated soffit
Clearance to outside corner
Clearance to inside corner
*
*
*
*
*
*
*
G
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.
36 in.
*
J
Clearance to non-mechanical air supply inlet to building or the
combustion air inlet to any other application
12 in.
K
L
Clearance to mechanical air supply inlet
72 in.
36 in. above if within 10 feet
horizontally
Clearance above paved sidewalk or paved driveway located on
public property
84 in. 3)
12 in. 4)
*
*
M
Clearance under veranda, porch deck or balcony
Table 7
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.”
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Installation instructions
Required other than direct vent terminal clearances (single pipe penetration)
6720608836-23.1Av
Fig. 12
1)
2)
Canadian installations
U.S. installations
A
B
Clearance above grade, veranda, porch, deck or balcony
Clearance to window or door that may be opened
12 in.
36 in.
12 in.
4 feet below or to side of opening;
1 foot above opening
C
D
Clearance to permanently closed window
*
*
*
*
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
F
Clearance to unventilated soffit
Clearance to outside corner
Clearance to inside corner
*
*
*
*
*
*
*
G
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.
36 in.
*
J
Clearance to non-mechanical air supply inlet to building or the
combustion air inlet to any other application
4 feet below or to side of opening;
1 foot above opening
K
L
Clearance to mechanical air supply inlet
72 in.
36 in. above if within 10 feet
horizontally
Clearance above paved sidewalk or paved driveway located on
public property
84 in. 3)
12 in. 4)
84 in.
*
M
Clearance under veranda, porch deck or balcony
Table 8
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.”
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Installation instructions
3.3.3 Venting configuration examples
Below are approved examples of horizontal
venting installations.
4"
HORIZONTAL RUN
1/4" PER FOOT
DOWN TO
TERMINATOR.
CONDENSATE
DRAIN
6720608542-05.2AL
Fig. 15 Horizontal twin pipe penetration
6720608542-02.2AL
Below are approved examples of vertical venting
installations.
Fig. 13 Horizontal side wall venting installation (single
pipe penetration)*
Important:
* Warning: for non-freezing climates only!
Note: Pitch horizontal runs down toward the heater,
1/4" per foot.
Important:
Note: Pitch horizontal runs down toward the heater,
except horizontal run between last elbow and termina-
tion which must slope down to termination 1/4" per
foot.
RAIN CAP
10' MIN.
2' MIN.
STORM COLLAR
3' MIN.
FLASHING
Note: For horizontal terminations, venting must
terminate once it penetrates to the outside of the
structure. There must be no sections of vent pipe
exposed to the outdoors.
FIRESTOP SUPPORT
4" MIN.
AIR SPACE
FIRESTOP SUPPORT
12"
HOSE
CLAMP
Min. 3 Feet
3” stainless steel pipe
ELBOW
CONDENSATE
DRAIN
APPLIANCE
6720608158-91.2Av
Fig. 16 Vertical venting installation (single pipe pene-
tration)*
6720608782-11.1Av
Fig. 14 Horizontal venting installation (concentric
penetration)
* Warning: for non-freezing climates only!
14
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3.3.4 Vent connections
B Attach the flue gas exhaust accessory (8 705 504
162) to the top of the unit (position 1) using the 4
screws and gasket provided. Fully insert stainless
steel vent pipe 1.5” minimum into the accessory and
tighten the clamp (position 2).
NOTE: Vent pipe must be completely ver-
tical when inserting or gasket inside ex-
haust accessory can become displaced.
Exhaust accessory can be removed with
vent pipe attached to check gasket posi-
tion.
i
Fig. 17 Vertical venting installation (twin pipe penetra-
tion)
RAIN CAP
10' MIN.
STORM COLLAR
FLASHING
2' MIN.
SILICONE SEAL
3' MIN.
Fig. 19
B Attach the combustion air inlet accessory (8 705
504 116) to the top of the unit (position 3) using the
3 screws and gasket provided, and install air intake
pipe over the accessory. NOTE: The appliance has
the option to mount the combustion air inlet acces-
sory 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.
CHIMNEY
MAY BE INSULATED
IF NECESSARY
HORIZONTAL RUN
1/4" RISE/FT
HANGER STRAP
MORTAR
ELBOW
ELBOW
HOSE
CLAMP
CONDENSATE
DRAIN
Fig. 20
B Ensure that exhaust vent pipe is fully inserted in collar
to enable proper connection.
APPLIANCE
Exhaust venting must be 3" or 4" sealed
single wall stainless steel (AL29-4C) vent
pipe.
6720608158-14.2AL
Fig. 18 Vertical venting installation - Masonry Chim-
ney (combustion air piping not shown)
i
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Installation instructions
3.3.5 Condensate drain installation
Note: Do not install condensate drain in areas where it
may freeze.
1. Install condensate drain as close to heater as possi-
ble.
2. Use 3/8" ID high temperature silicone tube to con-
nect to condensate drain port. Do not use copper pip-
ing for any portion of the condensate drain.
3. Form a condensate trap by means of a 3" loop par-
tially filled with water.
4. To increase the tube length, connect to end of the
high temperature silicone tubing with vinyl tubing, PVC
or CPVC pipe. Do not reduce the internal diameter at
any point.
5. Dispose of condensate according to local codes.
RAIN CAP
10' MIN.
2' MIN.
STORM COLLAR
3' MIN.
FLASHING
FIRESTOP SUPPORT
4" MIN.
AIR SPACE
ELBOW
CONDENSATE
DRAIN TEE
DRAIN TRAP
TO DRAIN - DISPOSE
OF CONDENSATE
ACCORDING TO
LOCAL CODES
APPLIANCE
6720608782-04.2Av
Fig. 21 Condensate drain installation (combustion air
piping not shown)
3" Venting
Z-flex
ProTech Heat Fab
90°
Condensate
Drain Tee
2SVEVWCF03 FST3 &
FSDF3
93PPLSTEE
Horizontal
Condensate
Drain
2SVEDWCF03 FSHDT3
9321
Condensate
Drain Tube
2SVEDTK24
N/A
7000TUBE
Table 9 Approved Condensate Drain Part Numbers
16
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Installation instructions
3.3.6 Fan speed adjustment
Example
Exhaust
IMPORTANT! Installation adjustment:
• 7 - 3' straight sections
After installing the water heater, the fan speed values for
minimum power (P2) and maximum power (P1) may
need adjustment due to variations in altitude and vent
pipe length.
• 1 - 1' straight section = Total straight pipe length 22’
• 2 - 90° elbow.
Intake
Failure to make necessary adjustments to fan speed
values may result in improper operation of the
appliance.
• 5 - 3' straight sections = Total straight pipe length 15’
• 1 - 90° elbows.
First calculate the total equivalent vent length. Use this
value to determine the appropriate fan speed values,
found in Table 12 and make any necessary
adjustments. After changing fan speed values proceed
to Section 6.4 to confirm CO2 values are within
specified ranges.
Example
Exhaust
Straight section length
(feet)
22 x 1 =
22
Total equivalent vent length calculation
90° elbows (qty)
45° elbows (qty)
Total:
1 x 2.5 =
2.5
0
B Determine the total length of all straight sections of
vent pipe and enter in table 10, line 1.
0 x 1.25 =
B Count the number of 90° elbows used and enter that
value in line 2. (Do not count terminals and first elbow
used on intake and exhaust).
24.5
B Count the number of 45° elbows used and enter that
value in line 3.
Intake
B Repeat steps 1 through 3 for air intake pipe and enter
those values in the intake section of table 10.
Straight section length
(feet)
15 x 1 =
15
B Add line 4 from Exhaust to line 4 of Intake and enter
result in line 5.
This is the total equivalent vent length.
90° elbows (qty)
45° elbows (qty)
Total:
1 x 2.5 =
0
0 x 1.25 =
0
Exhaust
15
39.5
1
2
3
4
Straight section length
(feet)
__ x 1 = ____
__ x 2.5 = ____
__ x 1.25 = ____
Total equivalent vent length =
Table 11 Determining vent length combination exam-
ple
90° elbows (qty)
Note: Do not count terminals and first elbow used on
intake and exhaust.
45° elbows (qty)
Total:
____
Total equivalent length must not to
exceed 57ft.
i
Intake
1
2
3
4
5
Straight section length
90° elbows (qty)
__ x 1 = ____
__ x 2.5 = ____
__ x 1.25 = ____
Total: ____
NOTE: If using concentric terminal include
exhaust pipe length that is part of the con-
centric terminal.
i
45° elbows (qty)
Total equivalent vent length = ____
Table 10 Determining vent length combination (see
example in Table 11)
17
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Installation instructions
Natural Gas
Maximum
power fan power fan speed power fan speed
Liquid propane
Maximum
Altitude
(above sea
level)
Total
equivalent
vent length1)
Minimum
speed (P2)
(P1)
(P1)
5.5 - 32 ft
33 - 57 ft
5.5 - 32 ft
33 - 57 ft
5.5 - 32 ft
33 - 57 ft
7
8
0 - 2000 ft
(0 - 610 m)
No
modification required
No
modification required
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
8*
8*
9*
9*
48*
49*
49*
50*
47*
48*
48*
49*
2000 - 4500 ft
(610 - 1372 m)
4500 - 8000 ft
(1372 - 2439 m)
* Above 2000 ft, CO2 levels must be checked with a combustion gas analyzer, see section 6.4 for instructions.
Table 12 Fan speed adjustment
1)
Full equivalent length (inlet + outlet piping + fittings)
Adjusting minimum power fan speed (P2)
Adjusting maximum power fan speed (P1)
To select fan speed:
To select fan speed:
B Press ON/OFF button into OFF.
B Press ON/OFF button into OFF.
B Press and hold "Program" button
ON/OFF button to turn appliance ON.
and press
B Press and hold "Program" button
ON/OFF button to turn appliance ON.
and press
Fig. 22
Fig. 23
B As soon as '188' is displayed, release "Program"
button
B As soon as '188' is displayed, release "Program" but-
ton
, and the display should read P2.
, and the display reads P2.
B Press
or to choose the fan speed suitable
B Press the minus button
B Press “Program” button
The current setting will appear on the display.
to display P1.
with your installation, see Table 12.
to enter P1 adjustment.
B Press and hold ( 5 sec.) “Program” button
until
the display flashes, then the selected value is memo-
rized.
B Press or to choose the fan speed suitable
with your installation, see Table 12.
B Press and hold ( 5 sec.) “Program” button
until
Do not set P2 to greater then 9.
the display flashes, then the selected value is memo-
rized.
i
Proceed directly to Section 6.4 to confirm
CO2 values are within range.
i
18
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Installation instructions
Attention residents of the Commonwealth of
Massachusetts:
signage installed in accordance with the provisions of
248 CMR 5.08(2)(a)1 through 4.
In the Commonwealth of Massachusetts the following
regulation went into effect on 12/30/2005:
(b) EXEMPTIONS: The following equipment is exempt
from 248 CMR 5.08(2)(a)1 through 4:
(a) For all side wall horizontally vented gas fueled
equipment installed in every dwelling, building or
structure used in whole or in part for residential
purposes, including those owned or operated by the
Commonwealth and where the side wall exhaust vent
termination is less than seven (7) feet above finished
grade in the area of the venting, including but not limited
to decks and porches, the following requirements shall
be satisfied:
1. The equipment listed in Chapter 10 entitled
"Equipment Not Required To Be Vented" in the most
current edition of NFPA 54 as adopted by the Board;
and
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. 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.
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:
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.
1. The referenced "special venting system" instructions
shall be included with the appliance or equipment
installation instructions; and
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. 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.
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".
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
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Installation instructions
below for providing adequate combustion air for the
water heater as well as any other appliances that may
consume air in the space. Always follow local codes if
they are more stringent.
3.4 Combustion air requirements
Warning: In areas where outside
temperatures routinely come close to
freezing, sealed combustion operation
is required. Use twin pipe or concentric
terminations for combustion air and
exhaust, 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.
When all requirements are followed, the unit will
operate properly and safely. However, there may still be
a risk of freezing due to negative draft if the other
combustion appliances in the building are not supplied
with sufficient combustion air. A wood stove or furnace
can pull its combustion air from the 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. Observe the following
guidelines:
Installations in structures that have been tightly
constructed (air infiltration rate of 0.40 ACH or less)
must be provided with combustion air per the National
Fuel Gas Code. Consult a HVAC specialist if your air
infiltration rate is questionable.
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.
The space must have two permanent openings, one
commencing within 12 inches of the top and one
commencing within 12 inches of the bottom of the
enclosure.
Twin pipe and Concentric pipe
The water heater is designed as a sealed combustion
appliance. It is recommended that the combustion air
be provided from the outside by a dedicated pipe (twin
pipe) or by connecting to the concentric vent kit (see
Fig. 8, 9 & 10). The combustion air pipe may be PVC
or any other rigid sealed 3" or 4" pipe. Horizontal
sections of the combustion air pipe must pitch down
towards termination 1/4" per foot to prevent rain water
from entering the appliance. When using the twin pipe
method, 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. 11 and
Fig. 12 Letter I, page 12.
Each opening must have a minimum free area of one
square inch per:
• 1000 Btu/hr if all air is taken from inside the building
• 2000 Btu/hr if all air is taken from the outside by
horizontal ducts
• 4000 Btu/hr if all air is taken from the outside by
direct openings or vertical ducts.
Or the space must be provided with one permanent
opening or duct that is within 12 inches of the ceiling of
the enclosure.
For the maximum length of the combustion air
inlet pipe, see table 6.
This opening must have a minimum free area of one
square inch per:
• 3000 Btu/hr if all air is taken from the outside by a
direct opening or vertical duct.
Warning: Vent terminations must
prevent rain from entering the
combustion air and exhaust vent piping.
Louvers, grills and screens have a blocking effect. If the
effective free area is not known, increase the sizes of
your openings by 300% if your louvers are wood and by
43% if your louvers are metal. Refer to the National Fuel
Gas Code for complete information.
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 outside (see twin pipe system above).
Although it is permissible to draw combustion air from
inside the structure, it is not the manufacturer’s
recommended installation method. Always install a 3
inch 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
20
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Installation instructions
3.5 Proper location for installing your
heater
3.7 Mounting installation
Warning: before starting
installation
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.
B Check that there are no loose or
the
damaged
appliance
parts
inside
Follow the guidelines below:
B Confirm the gas type of the heater
matches the gas supply you will be
connecting the heater, see Fig. 2,
page 6.
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.
Front cover should be removed (see
instructions on page 6) in order to inspect
components visually.
i
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.
Warning: Do not install this appliance
on a carpeted wall. The heater must be
mounted on a wall using appropriate
anchoring materials.
See chapter 6.2, page 32 “Winterizing”
for draining instructions.
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.
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.
If wall is sheathed with plaster or drywall, it is recom-
mended that two support boards, either 1”x4” or 1/2"
(minimum) plywood first be attached across a pair of
studs, see Fig. 24.
B Secure the wall mounting bracket provided with the
heater to the wall surface. The heater must be kept
level on the wall surface (see Fig. 25).
3.6 Heater placement and clearances
The water heater 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 non-combustible materials. See Fig. 7
and Table 1 on page 8.
B Hang the appliance on the bracket, see Fig. 26.
Clearances from any exhaust vent pipe are dependent
upon the clearance requirements of the stainless steel
vent pipe manufacturer. Single wall stainless steel
(AL29-4C) vent pipe (vent type rated for Category III
appliances) must be used when exhaust venting this
appliance. See chapter 3.3 (page 9) Venting.
Studs 16"
(406mm) on
center
Fig. 24 Distance between support boards
21
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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 CSA B149
INSTALLATION CODES and/or local installation
codes.
Warning: DO NOT connect to an
unregulated or high pressure propane
line or to a high pressure commercial
natural gas line.
6720608158-64.1AL
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.
Fig. 25 Leveling the mounting bracket on the studs
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”.
B Undersized flexible appliance connectors 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 sup-
plier, see Fig. 27.
6720608158-05.1AL
Fig. 26 Mounting the heater
Warning: Appliance must be installed
vertically.
Gas supply
Minimum
3”
Cap
Fig. 27 Gas connection (drip leg)
22
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Installation instructions
Once connections are made, check for gas leaks at all
joints. Apply some gas leak detection solution to all gas
fittings. Bubbles are a sign of a leak. A combustible gas
detector may also be used to detect for leaks.
Danger: If you have a leak, shut off the
gas. Tighten appropriate fittings to stop
leak. Turn the gas on and check again
with a gas leak detection solution.
Never test for gas leaks using a match
or flame.
GAS LINE SIZING
The gas supply piping for a single heater should be
sized for a maximum draw of 199,000 BTUH. Measure
the length of gas supply line and use the tables in
Fig. 29, page 24 or the gas line manufacturer’s sizing
tables to determine the pipe diameter necessary to
accommodate the 199,000 BTU demand of the heater.
If there are more gas appliances on the line, size the gas
line according to the total maximum amount of BTU
input rating for all appliances.
Note: Undersizing the gas line may result in diminished
hot water flow rate and temperature. See chapter 3.12,
page 27 for the procedure to confirm gas pressure.
Proper gas pressure must be confirmed at time of
installation.
Inlet gas particle screen
(included)
Gas piping
Fig. 28
23
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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 GWH 2700 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
Iron
Length of Black iron Pipe , Feet
Pipe
Size,
Internal
Diameter
inches inches
10
20
30
40
50
60
70
80
90
100
125
150
175 200
1/4
3/8
1/2
0.364
32
72
22
49
92
18
40
73
15
34
63
14
30
56
12
27
50
11
25
46
11
23
43
10
22
40
9
8
8
7
6
0.493
0.622
21
38
18
34
17
31
15
28
14
26
132
3/4
1
0.824
1.049
1.380
1.610
2.067
278
520
190
350
152
285
590
890
130
245
500
760
115 105
96
90
84
79
72
64
59
55
215 195 180
440 400 370
670 610 560
170
350
530
160
320
490
930
150
305
460
870
130
275
410
780
120
250
380
710
110 100
225 210
350 320
650 610
1 1/4
1 1/2
2
1050
1600
3050
730
1100
2100 1650 1450
1270 1150 1050 990
Length of Flexible Corrugated Stainless Steel Tubing (CSST), Feet
Tube
size,
inches
EHD*
10
20
58
30
47
96
40
41
50
37
60
34
1/2
3/4
1
18 EHD 82
23 EHD 161 116
83
75
68
30 EHD 330 231 188
162
325
144
292
131
267
* EHD = Equivalent Hydraulic Diameter. The greater the
value of EHD, the greater the gas capacity of the tubing
.
1 1/4 37 EHD 639 456 374
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
iron
Length of Flexible Corrugated Stainless Steel Tubing (CSST), Feet
Tube
size
Black Iron Pipe
pipe
Length of Pipe, Feet
inches
EHD*
Inches
10
20
30
40
50
60
80 100 125 150 200
10
20
30
74
40
64
50
58
60
53
1/2
3/4
1
291 200 160 137 122 110 94
84 74 67 58
1/2
3/4
1
18 EHD 129 91
608 418 336 287 255 231 197 175 155 140 120
1145 787 632 541 480 434 372 330 292 265 227
23 EHD 254 183 151
30 EHD 521 365 297
131
256
118
227
107
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
Outside
diameter
Inch
Length of Tubing, Feet
10 20
39 26
92 62
30 40
21 19
50 41
50
_
60 70 80 90 100
3/8
1/2
_
_
_
_
_
37
79
35 31 29 27 26
72 67 62 59 55
(Based on a Pressure Drop of 0.5 Inch Water Column)
5/8 199 131 107 90
* Source National Fuel Gas Code NFPA 54, ANSI
Z223.1 - No Additional Allowance is necessary for an
ordinary number of fittings
3/4 329 216 181 145 131 121 112 104 95 90
Fig. 29
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Installation instructions
or flush the lines before connecting to the water
heater.
3.9 Water connections
Warning: This heater is not approved
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. 31).
for preheated water applications.
See chapter 3.11 for approved
recirculating application.
B For installation on a private well system with the use
of a pressure tank, the lowest pressure range setting
recommended is 40-60 psi (2.75 and 4.15 bar).
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.
3.10 Water quality
Water quality can have an impact on appliance
longevity and may not be covered under the
manufacturer's warranty.
For water analysis data call your local water department,
or if on a well, have well water analyzed periodically. If
water quality exceeds one or more of the values
specified below, Bosch recommends consulting a local
water treatment professional for water softening/
conditioning options.
B When facing the heater, the ¾” cold connection is on
the bottom right and the hot connection is on the bot-
tom left. Centrally locating the water heater is recom-
mended to keep hot water distribution times even
throughout the structure.
Description
pH
Max. Levels
pH
6.5 - 8.5
500
TDS (total Dissolved
Solids)
mg/l or ppm
mg/l or ppm
mg/l or ppm
mg/l or ppm
mg/l or ppm
mg/l or ppm
mg/l or ppm
mg/l or ppm
100
(6 grains)
Total hardness
Aluminum
Chlorides
Copper
COLD
2.0
250
1.0
HOT
Fig. 30
B The use of unions when connecting both water
pipes to the inlet and outlet connections is
required. This will facilitate any necessary
servicing.
Iron
0.3
B Plastic or PEX type plumbing line materials are not
suitable for connecting directly to the water heater.
Manganese
0.05
5.0
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).
Zinc
Table 13
B Never sweat any piping directly to or beneath
the water connections, as damage can occur to
the internal water valve from heating of the
pipe.
B Keep water inlet and outlet pipes to no less
than ¾" (19.05mm) diameter to allow the full
flow capacity.
B If the cold and hot connections to the heater are
reversed, the heater will not function. Be certain there
are no loose particles or dirt in the piping. Blow out
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Installation instructions
Connecting the pressure relief valve (PRV)
3.11 Domestic hot water recirculation
A listed pressure relief valve supplied with the heater
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 min-
imum 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. 31. To install the
PRV, a suitable fitting connected to an extension on a
“T” fitting can be sweated to the hot water line.
Support all piping.
Although recirculation directly through the tankless
water heater is allowed, temperature stability is
improved by recirculating through a mini-tank as shown
in Fig. 32. By using the design in Fig. 32, 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.
GWH
2700
ES
5
2
4
1
3
Fig. 31 Plumbing Connections (with shutoff valves)
and Pressure Relief Valve
6720608158-77.1AL
Ariston Minitank
1
Water filter
Fig. 32 Recirculation application
1
2
3
4
5
Full port isolation valve
Circulator (pump)
Check valve
PRV
Expansion tank
The use of a small electric mini-tank water heater (4-6
gallon size) should be used for this application and
designed so the pump will circulate the water through
the mini-tank and the building's hot water return loop
only. Timed or thermostatically controlled operation of
the pump is commonly done. Contact Bosch
Thermotechnology if further information is needed.
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Installation instructions
B Record lowest operating gas pressure reading in
table 15.
3.12 Measuring gas pressure
Confirm gas pressure upon installation.
Connecting manometer
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 22.
B Shut off gas supply at installer supplied shutoff valve
for this water heater.
B Remove front cover and locate inlet gas pressure
measuring point (see Fig. 34).
B Loosen screw inside left test point fitting (do not
remove) and connect manometer tube to test point.
Remove screw completely if correct size tapping is
available.
Static Pressure Test
B Turn gas supply back on.
B Record static gas pressure reading in table 15.
Operating Pressure Test
B Press ON/OFF button to turn off the appliance.
B Press and hold "Program" (P) button and press ON/
OFF button to turn appliance ON.
Fig. 34 Gas pressure test port (left tapping)
Static Gas Pressure Reading (see Chapter 3.12)
enter here: ___________________ Date: ___________
Operating Gas Pressure Reading (see Chapter 3.12)
enter here: ___________________ Date: ___________
Table 15
Fig. 33
B As soon as '188' is displayed, release "Program"
, button and the display should read P2.
B Press
or
until P1 appears.
Note: While in this mode the appliance will run
constantly at maximum power and allow
maximum water flow.
For inlet gas pressure adjustment consider the
following table:
Gas type
NG
LPG
3.5” WC
8” WC
Table 14
Minimum inlet gas pressure under full operation
B Turn on high volume of hot water flow (at least 6
gpm) and heater will ignite. If heater display reverts to
P2, open more hot water fixtures to allow sufficient
flow. Press
until P1 reappears on display.
B Operate all other gas appliances on the same gas
piping system at maximum output.
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Electrical connections
4
Electrical connections
4.1 Electrical power supply
4.2 Position of the fuses in control unit
To check fuses, proceed as follows:
Warning:
For
safety
reasons,
B Remove the front cover, see Fig. 4, page 6.
disconnect the power supply cord to
the heater before any service or testing
is performed.
B Remove the three screws on front of the control unit.
Warning: This heater must be
electrically grounded in accordance
with the most recent edition of the
National Electrical Code. NFPA 70. In
Canada, all electrical wiring to the
heater should be in accordance with
local codes and the Canadian Electrical
Code, CSA C22.1 Part 1. Do not rely
on the gas or water piping to ground the
metal parts of the heater.
Fig. 36
B Pull control unit free to access and remove the six
screws from the back cover of the control unit, see
Fig. 37, pos. 2.
The water heater requires an electrical power supply
from a 120VAC / 60Hz properly rated receptacle and
must be properly grounded.
B Check the fuses in the printed circuit board, see Fig.
37, pos. 3.
The heater is wired as shown in the wiring diagram
(chapter 9, Fig. 59).
1
2
Fig. 35 Connecting power supply cord
3
1
Power cord length: 3ft.
Note: Outlet appliance is plugged in to should be
clear from possible water damage.
6720608158-78.1AL
Fig. 37 Location of fuses
B After verifying the fuses mount all parts in reverse
order.
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Operation instructions
5
Operation instructions
Fig. 38
1
2
3
4
5
6
7
On/Off button
Reset button
Program Key
LCD display
Up button
Down button
LED - Power On indicator or Stand-by
5.1 LCD Display functions
Fig. 42 Lock indicator
Fig. 43 Flame indicator
Fig. 44 Remote control
Warning: Do not use any cleaning or
corrosive agent to clean the window.
Fig. 39 Power bar indicator
Fig. 40 Temperature indicator
Fig. 41 Error indicator
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Operation instructions
5.2 For your safety read before
operating your water heater
5.4 Temperature selection
To select output water temperature:
B Press buttons
temperature.
or
in order to reach desired
Warning: If you do not follow these
instructions exactly, a fire or explosion
may result causing property damage,
personal injury or loss of life.
A. This appliance is equipped with electronic ignition for
lighting the main burner. When turning the heater on,
follow these instructions exactly.
B. Before operating the unit, press the On/Off button.
WHAT TO DO IF YOU SMELL GAS
B Do not try to light any appliance.
B Do not touch any electric switch; do not use any
phone in your building.
Fig. 46
B Immediately call your gas supplier from a neighbors
phone. Follow the gas supplier’s instructions.
Setting the water temperature
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.
B If you cannot reach your gas supplier, call the fire
department.
C. Use only your hand to press the on/off control switch.
Never use tools. Follow these instructions exactly. If
control switch is jammed, close the gas supply and call
a qualified service technician. Attempted forceful repair
may result in a fire or explosion.
D. Do not use this appliance if any part has been under
water. Immediately call a qualified service technician to
inspect the appliance and to replace any part of the
control system and any gas control which has been
under water.
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.
Saving water resources:
B Make sure you close all the taps after any use. Avoid
leaving the taps dripping. Repair any leaking tap.
5.3 Power
On
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).
B To start the appliance press the On/Off button.
Fig. 45
Off
B To shut down the appliance press the On/Off button
again.
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Operation instructions
5.5 Use of optional remote control
accessory (part no. TSTAT2)
Fig. 50 Reset button
If the problem persists, contact your installer.
5.8 Program button
Program button can be used on the appliance and in the
remote control.
Fig. 47 Remote control
The wireless remote control accessory (Fig. 71,
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
control unit (Fig. 71, component 16) is required when
programming the remote control with this heater.
Programming “Program” function
Programming actions are similar for both controls
(appliance control pad and wireless remote control).
NOTE: up to 6 remote controls can be
programmed for one single water heater,
each with a range distance of 98 ft (30 m).
i
Fig. 51 “Program” key
5.6 Operation
B When a hot water tap is opened, main burner ignites
and LCD displays the symbol
Memorizing selected temperature
.
B Press buttons
memorized.
or
to select temperature to be
B Hold “Program” button for 3 seconds to save
temperature.
When LCD stops blinking, temperature is saved in
memory.
Fig. 48
Using “Program” function
In order to select memorized temperature
B LCD blinks until selected temperature is reached.
B Press “Program” key.
5.7 Reset button
LCD shows pre-memorized temperature, which is now
the hot water selected temperature.
If the LCD shows the error symbol
power or unplug the heater.
do not shut off
See the error code on LCD and consult
“Troubleshooting” section.
5.9 Locked condition
This condition is only valid for appliances with remote
controls.
Fig. 52 Locked condition
Fig. 49
Whenever LCD shows
the temperature setting
After
“Troubleshooting” section.
following
instructions
indicated
in
cannot be adjusted because the appliance is in use by
a user which already selected a different temperature.
Appliance will be automatically unlocked five minutes
after closing the hot water tap.
B press reset button to return heater to normal
operation.
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Maintenance and service
6
Maintenance and service
Pressure relief valve
Warning: Always turn off the electrical
power supply, turn off the manual gas
shut off valve and turn off the water shut
off valves whenever servicing.
• Manually open the pressure relief valve to ensure
proper operation.
Inlet water filter
• Verify the inlet filter screen is clean and undamaged.
The inlet water filter is located inside the cold water
inlet fitting on the right side of the appliance (See
Fig. 53, page 32). Close installer supplied cold water
shutoff and loosen slotted screw on inlet fitting.
Water will drain from the appliance. Remove
cylindrical filter inside.
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
1. Inspect venting system
X
X
X
X
X
2. Inspect combustion chamber
3. Inspect burner
4. Inspect condensate trap
5. Inspect water filter
Table 16 Annual maintenance
Fig. 53 Water filter
The unit should be checked once a year by a gas
technician. If repairs are needed, the repairs should be
done by a gas technician.
1
2
Inlet water filter
Water filter
Descaling
• In areas where the water supply has a high mineral
content (see Table 13, page 25), the heat exchanger
should be periodically flushed with a descaling
solution. Scale build up will shorten the life of the
water heater and damage resulting from scale is not
covered under warranty. Refer to section 6.3 for
detailed instructions on descaling the heat
exchanger.
6.1 Annual maintenance
(To remove front cover, see page 6.)
Venting System
• Venting system - inspect inside of flue pipe for any
blockage or restriction. Observe burner flames
during heater operation. (Vent pipe must be
removed). Inspect the combustion air inlet pipe for
blockage or debris. Inspect combustion air and
exhaust terminations for blockage or debris.
Heat exchanger fin coils
• Inspect heat exchanger fincoil for soot build-up or
blockage. To access fincoil, venting must be
removed from flue gas exhaust accessory. With
venting removed and inspect fincoil below with a
flashlight. If there is evidence of soot build-up or
blockage, the heat exchanger should be removed by
a professsional and cleaned thoroughly. To remove
the heat exchanger, consult service bulletin at
Combustion chamber
• Inspect burner observation window (Fig. 64, #10) for
cracks or spillage of flue gases. Observe burner
flames during heater operation. Flames should be
steady and blue with no signs of yellowing. Yellow
burner flames are an indication of improper
combustion. Refer to Section 3.4 & 3.3 of this
manual to ensure that exhaust system and
combustion air supply meets manufacturer's
specifications.
6.2 Winterizing for seasonal use
Installation instructions state that the water heater must
not be installed in a location where it may be exposed to
freezing temperatures. If the heater must be left in a
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Maintenance and service
space which is likely to experience freezing
temperatures, all water must be drained from the heater.
If precautions are not taken, resulting damage will not
be covered under the warranty. NOTE: Use of agents
such as anti-freeze is not permitted as they may cause
damage to the water heater's internal components.
9. Fill tank with descaling solution so both lines inside
are submersed. We recommend straight white
vinegar. If using a commercial descalant, refer to
manufacturer's instructions on dilution with water.
10.Operate the circulating pump.
11.Make sure there are no leaks and the solution is
flowing from the descaling reservoir through the
heater and returning to the reservoir.
1. Press ON/OFF switch on the water heater to turn
OFF the heater and unplug power supply cord. The
display should be blank.
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).
2. Shut off gas supply to heater.
3. Shut off the water supply to the water heater using
installer supplied shutoff valve.
13.Disconnect all lines and drain all solution from heat
exchanger. Properly discard of solution.
4. Open hot water taps to drain the plumbing system. If
water continues to flow after 5 minutes, a plumbing
crossover is present and must be corrected before
proceeding.
14.Position a container below the hot water outlet and
connect cold water supply. Open cold water supply
isolation valve and flush heat exchanger with clean
water.
5. Open service valves (if available) or disconnect inlet
and outlet water pipes from the water heater. Place a
small bucket underneath the water heater to catch
residual water remaining inside the water heater.
15.Shut cold water shutoff valve and reconnect hot
water supply to the water heater.
6. Using an air compressor, blow short bursts of air
(100psi max) through the outlet water connection
until there is no water present coming through the
inlet water connection of the heater.
16.Reconnect electrical supply to unit, open water
shutoff valves, and return the unit to service.
7. Reconnect water fittings and return heater to service
when danger of freezing has past.
6.3 Mineral scale build-up
Periodic descaling may be necessary in areas with high
mineral content in the water. Scale buildup in the heat
exchanger may result in lower flow rates, error codes of
A7 and E9 and boiling sounds (knocking and banging)
in the heat exchanger.
Descaling using a pump
1. Disconnect electrical supply from the water heater.
2. Shut off the water supply to the water heater using
(installer supplied) shutoff valve.
3. Open hot water taps to drain and relieve pressure
from the plumbing system.
4. Drain water from the unit's heat exchanger by
disconnecting inlet and outlet water connections
from the heater.
Fig. 54
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. 54).
6.4 Adjusting CO (carbon dioxide)
2
The CO2 can only be adjusted by a certified gas
technician with a calibrated CO2 analyzer.
6. Using another line (B), connect to the water outlet
fitting on the water heater. Route the other end of this
line into a descaling reservoir.
Caution: One factor that may affect
CO2 levels is improper gas pressure.
Please see Chapter 3.12 for the
procedure to measure gas pressure
and record your findings below:
7. Using a 3rd line (C) from the descaling reservoir,
connect to the inlet side of circulating pump. Install a
filter on the end of this line in the descaling reservoir.
8. Make sure all connections are "water tight.".
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Maintenance and service
Static Gas Pressure:
“ WC
“ WC
B Record the CO2 reading in P1 below. (Analyzer
reading may take several minutes to stabilize).
P1 Operating Pressure:
B Press the ‘ ’ button until P2 appears. Unit will
ramp down to low fire and the flow should decrease.
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.
B Record the CO2 reading in P1 and P2 below.
P2 CO2 Reading:
% CO2
P1 CO2 Reading:
% CO2
A. Once Gas Pressure is adequate
C. Adjusting CO2:
B Press ON/OFF button to turn off the heater.
Note: P1 adjustment will change the P2 reading.
Confirm the P1 value BEFORE adjusting the P2 level.
B Remove brass flat head screw on the exhaust collar
as seen in Fig. 55.
1. If P1 CO2 level is off:
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.
B Loosen yellow painted philips screw (1) and cover
should rotate down (2) revealing a recessed brass
slotted screw. Fig. 57.
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:
B Remove yellow painted #40 Torx cover from the front
of the gas valve. (Fig. 58) A plastic #40 Torx screw
will be revealed.
Fig. 55 Measuring port
B Turning the plastic #40 Torx screw counter
clockwise will lower P2 CO2 levels and clockwise
will raise P2 CO2 levels.
B While holding the Program (P) button in, press the
ON/OFF button to turn ON the heater (see Fig. 56).
As soon as ‘188’ flashes on the display, release the
Program button. The display should now read P2.
Note: This screw adjustment is very sensitive and
should be made in small increments. It may take several
minutes for readings to stabilize.
Press
button until “P1” appears on display.
3. Verify both P1 and P2 CO2 readings are within the
ranges specified in table 17. Repeat steps 1 and 2 as
necesssary until CO2 values are within the specified
ranges.
4. Once CO2 values are within the specified ranges,
verify the CO readings on P1 and P2 do not exceed
values shown in table 17. If values exceed this limit,
inspect vent system and fin coils (chapter 6.1, page 32)
for blockage.
D. Returning to Service:
Fig. 56
1. Return slotted screw cover to original position and
tighten philips screw.
2. Reinstall Torx cover.
B. Measuring CO2 (combustion cover must be
installed):
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.
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 to P2, open
more hot water fixtures to allow sufficient flow. Press
5. Heater is ready for normal operation.
‘
’ until P1 reappears on the display.
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Maintenance and service
Max. CO
level
(measured)
CO2 range (%)
Nat. Gas
7.5 % - 8.1 %
2.3 % - 2.6 %
LP Gas
max. input
min. input
P1
P2
< 250 ppm
< 60 ppm
max. input
min. input
P1
P2
8.7 % - 9.3 %
2.7 % - 3.0 %
< 250 ppm
< 60 ppm
* Values above are for climate controlled conditions.
Inputs such as gas pressure, heating value of the gas,
humidity and temperature of combustion air all impact CO
and CO2 values. Changes in these inputs can result in
different CO and CO2 values on the same appliance.
Table 17 CO2 & CO target numbers
Final Readings
P2 CO2 Reading:
% CO2
% CO2
P1 CO2 Reading:
Fig. 57 Adjusting P1 CO2 level
6720608158-38.1AL
Fig. 58 Adjusting P2 CO2 level
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Maintenance and service
Refer to chapter 6.6 Control board diagnostics (page
37) regarding how to access these P-modes.
6.5 Program values
This section describes details on programming the
appliance. For most applications the factory default
values will 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: 48, LP: 46
21
NG: 50, LP: 49 see chapter 3.12, page 27.
note: reducing P1 values below
maximum will reduce maximum
power of the appliance.
P2
P3
Minimum Power
7
7
20
6
see chapter 3.3.6, page 17
see chapter 5.5, page 31
Remote Con-
trols installed
_0
_0
P4
Access to Diag-
nostic Mode
E
0d
10f
see chapter 6.6, page 37
contact Bosch for details
P5
P6
Cascade Mode
NO
°F
NO
°F
CC
°C
Temperature
Unit
P7
P8
Appliance Type
Back light
NO
dE
Cd
dE
NO
ON
Condensing / Non-condensing*
dE turns back light off after 60
seconds from last button
pushed, ON turns backlight on
permanently
P9
Fan Purge
runs secondary and primary fan
when P9 is selected by
depressing the “P” - button
Table 18 Program values, factory default settings and ranges.
* Incorrect setting causes errors.
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Maintenance and service
6.6 Control board diagnostics
Diagnostic menu
1. Turn on/off switch on water heater to off (O) position.
E
Entry/Exit into sub-modes
Set-point temperature (°F)
2. Press and hold the program (
) button while
0d
1d
2d
3d
4d
5d
6d
7d
8d
9d
turning the on/off switch to the on (I) position. The
display will cycle through a startup procedure
including the software version.
Inlet water temperature (°F)
Outlet water temperature (°F)
Water flow (gallons/min)
Gas type (LP or NG)
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
Fan speed (Hz)
panel until the display reads 'P4'. You are now in the
diagnostic mode of the control board.
Burner power (%)
Maximum power (kW)
Back flow temperature (°F)
5. When the display reads 'P4', press and release the
'
'E'.
' button once again and the display should read
Flue gas temperature (°F)1)
not used, settting 00
6. Use the '
' and '
' button on the control board
to cycle through different diagnostic modes
available.
1F
2F
3F
4F
5F
6F
7F
8F
9F
Most recent error/failure
2nd most recent error
3rd most recent error
4th most recent error
5th most recent error
6th most recent error
7th most recent error
8th most recent error
9th most recent error
10th most recent error
7. Once in the selected diagnostic mode of your
choice, press and release the '
the diagnostic information.
' button to display
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.
10F
9. To exit the diagnostic mode of the heater, use the
'
Table 19
' or '
' button until the display reads 'E'.
1)
Available only on model GWH C800 ES
10.Press the '
should read P4.
' button once again and the display
11.Turn the on/off switch off (O) and back on (I) again
to return heater to normal function.
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Troubleshooting
7
Troubleshooting
and mixing valves are common causes of plumbing
crossovers.
Warning: If you are unable to perform
the tasks listed below, or need
additional assistance please contact
your original installer or licensed gas
technician.
8. With the ON/OFF switch turned to OFF (O) position
and the power supply cord unplugged, remove the
unit's front cover (See Page 6. Fig 3). Check wire
connections between the water valve, control unit
and electrode set. See chapter 12.1, page 49 for
location of these parts.
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
troubleshooting and service bulletins. For best results,
perform each step before proceeding to the next. The
suggested solutions may require that the cover be taken
off. (See Page 6. Fig. 3).
7.3 Water is too hot
1. Selected temperature on the unit is set too high. To
lower output temperature, see chapter 5.4, page 30.
2. Clean inlet filter screen per chapter 6.1, page 32.
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.
7.2 Burner do not ignite when hot
water is turned ON
1. If the display is blank, verify power to outlet.
(120VAC/60Hz properly grounded circuit required).
Verify that the heater ON/OFF button is turned ON.
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.
2. Verify the fuses in the control board are good. See
Section 4.2, page 28 of the installation manual for
fuse locations.
6. In areas where the water has a high mineral content,
periodic descaling may necessary. See chapter 6.3,
page 33 for directions.
3. Make sure cold water inlet connection is plumbed to
the right side of heater when facing unit. See Fig. 30,
page 25.
7. Ensure the outlet temperature sensor is making
contact and firmly mounted on the hot water pipe.
4. A minimum of 0.65 gallons per minute (GPM) (2.5 l/
m) is required to activate the heater. A quart
container should fill in 25 seconds or less to activate
heater. In areas of warm inlet water temperatures, the
heater may increase activation rate to as high as 1.6
gallons per minute (GPM) to prevent overshooting of
set temperature.
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 30.
2. Clean inlet filter screen. See chapter 6.1, page 32.
3. Inspect the water path for obstructions. Make sure all
showerheads, faucet aerators and whole house
filters are clear of debris.
5. Clean inlet filter screen per chapter 6.2, page 32.
6. 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.
7. The heater activates when the water flow through the
unit is at or above the required minimum of 0.65
GPM (2.5 l/m). A crossover in the plumbing creates
back pressure on the water flowing through the
heater. Therefore, a higher flow rate than normal is
needed to force the heater to activate. To check for
a plumbing crossover, shut off the cold water supply
to the water heater. Then open all of the hot water
taps served by the heater. Wait 10 minutes and
check for water flow at taps. There should be no
water flowing. Any continuous flow of water, small or
large, indicates a crossover is present and must be
corrected. Consult a professional plumber for help in
correcting a crossover. Failing single lever faucets
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 3.12, page 27. 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
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Troubleshooting
heater. Then open all of the hot water taps served by
the heater. Wait 10 minutes and check all taps for
water flow. There should be no water flowing. Any
continuous flow of water, small or large, indicates a
crossover and must be corrected. Consult a
professional plumber for help in correcting a
crossover. Failing single lever faucets and mixing
valves are common causes of plumbing crossovers.
higher pressure cold water at the tap, the lower
pressure hot water can be overpowered. This will
shut down the burners because the hot water flow
rate fell below the minimum flow rate required for
activation. Verify inlet filter screen is clean and clear
of debris. See chapter 6.1, page 32 for inlet filter
cleaning instructions.
3. Heater deactivated by temperature balancing valves.
If the outlet water temperature is set too high, the
heater can produce temperatures that are too hot. A
temperature balance shower valve will automatically
mix in cold water to reduce the hot water
temperature. In the event of any temperature
instability at a fixture using a temperature balancing
valve, refer to the valve manufacturer for instructions
on internal adjustment setting. An adjustment should
be made to minimize the amount of cold water the
valve is adding. Additionally, the temperature setting
on the heater can be lowered to prevent the
temperature balance valve from mixing in too much
cold water.
8. Ensure the outlet 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 3.12, page 27. 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.
4. Inlet water pressure is erratic due to fluctuating
supply water pressure. For installation on a private
well system with the use of a pressure tank, the
lowest pressure range setting recommended is 40-
60 psi (2.75 - 4.15 bar). Consult your installer or
local plumber for effective ways to maintain constant
water pressure to the water heater when on a well
system.
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.
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.
4. Clean inlet filter screen per chapter 6.1, page 32.
5. Inspect the water path for obstructions. Make sure all
showerheads, faucet aerators and whole house
filters are clear of debris.
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 proper and in accordance with
specifications in chapter 3.3, page 9.
7.6 Hot water temperature fluctuates
at tap
1. Hot water is very hot out of the tap, requiring mixing
of cold water in order to attain a useable hot water
temperature. The addition of too much cold water will
overpower the hot water flow from the tankless water
heater.
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 use of piping for combustion air will result
in unstable burner flames and noise. Ensure
adequate combustion air is provided to the unit in
accordance with specifications in Section 3.4, page
20, Combustion Air Requirements.
This slows the flow within the tankless water heater,
decreasing it below activation point, which shuts off
the burners. The end result is nothing but cold water
coming out of the outlet.
service bulletin on overcoming temperature
fluctuations.
4. Cross contamination. Ensure that intake and exhaust
terminations maintain minimum required clearances
stated in the manual. Cross contamination between
intake and exhaust may cause unstable burner flames
and noise.
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
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Troubleshooting
5. Lack of adequate gas pressure. Inadequate gas
pressure will cause the fuel-to-air mixture (CO2) to be
out of adjustment. This will result in unstable burner
flames and noise. Ensure gas pressure is in
accordance with specifications in section 3.12, page
27 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 6.4, page
33. CO2 adjustments must be done by a certified
gas technician with a calibrated combustion gas
analyzer.
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Problem solving
8
Problem solving
8.1 Error code diagnostics
To remove error code from the
display, press the reset button.
i
Display
Cause
Solution
Fault in the flue gas limiter.
1. Check continuity of the flue gas limiter (see Fig. 64, page 49).
Go to steps two and three to determine air box temperature
sensor fault and replace it.
2. Check for flue gas leakage around the top and bottom seals of
heat exchanger as well as the viewing window.
3. Check that venting is within specifications (see Section 3.3).
Long vent lengths, venting with more than three elbows, blocked
vent or combination venting may cause this failure.
4. Check that flue gas limiter connector and spade connections
are secure.
5. Unplug heater and check the two main plug connections inside
the control board.
Appliance selection on “P7” mode 1. Check “P7” mode: water heater requires setting “NC”.
is not correct.
2. Check jumper and connection on sensor at upper right hand
corner of heat exchanger.
3. Measure jumper resistance, must be 115-125 ohms.
Backflow temperature sensor 1. Check backflow temperature sensor connection and resistance.
defect - happens if sensor is See Fig. 62 page 47 and Fig. 64, page 49
disconnected or short circuit. 2. Replace backflow temperature sensor.
,
.
Outlet temperature sensor fault 1. Check red wire connections at hot water temperature sensor.
(Temperature below freezing or Clean terminals with an eraser. If badly corroded, replace sensor
above 210°F).
and wire harness. See Fig. 64, page 49.
2. Sensor may trip if water temperature drops below freezing to
protect heater from freezing conditions. Any damage due to
freezing conditions is not covered under warranty.
3. Clean inlet filter screen and clear any debris out of shower
heads, faucet aerators and whole house filters.
4. In areas where water has a high mineral content, periodic
descaling may be necessary.
Table 20
* By installer or service technician only.
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Problem solving
Display
Cause
Solution
(Flashing)
Outlet temperature sensor not 1. Check that the sensor is firmly attached to the hot water pipe
expected
sensing
temperature.
output (see Fig. 70, page 55).
2. Clean inlet filter screen and clear any debris out of shower
heads, faucet aerators and whole house filters.
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. Check gas pressure. Low gas pressure may prevent the heater
from reaching desired output temperature.
5. Check supply voltage. It must be 120VAC and properly
grounded.
6. Possible defective control unit call Bosch Water Heating for
further instructions.
7. Ensure that outlet temperature sensor is not placed on any
bends in the hot water pipe or misreading may occur.
Primary fan rotation too low on 1. Disconnect power supply cord and check wire connections on
operation.
back side of primary fan and the two connectors on the control
board (see Fig. 71, page 56).
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
minimum 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 1. Disconnect power supply cord and check wire connections on
from primary fan.
back side of primary fan and the two connectors on the control
board (see Fig. 71, page 56).
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.
(Flashing)
Water flow signal over specified 1. Disconnect power supply cord and check wire connections on
water valve and the two connectors on the control board (see
Fig. 71, page 56).
maximum value.
Water flow > 10 gallon/min.
2. Excessive water pressure and flow. Ensure water pressure is
less than 150psi and flow rate is below 10 gallons per minute.
Internal hardware/software failure.
1. Disconnect power supply cord and check the two wire and
ground connections on control board as well as ground connection
on heater chassis.
2. Pushing the wrong combination of buttons on the control unit
can create confusion among the microprocessors inside. In this
case, the error code should not happen more than once or twice.
Turn off the water heater. Turn water heater back on and try
resetting error code. Use the reset button (
codes.
) to reset any error
3. Possible defective control unit. Call Bosch Water Heating for
further instructions.
Table 20
* By installer or service technician only.
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Problem solving
Display
Cause
Solution
Over-temperature detected by 1. Check that the sensor is firmly attached to the vertical section of
outlet temperature sensor on hot the hot water pipe (see Fig. 70, page 55).
water pipe.
Temperature > 185°F
2. Check red wire connections at outlet temperature sensor.
Clean terminals with an eraser. If badly corroded, replace sensor
and wire harness. Check sensor resistance (see Fig. 60
46
3. Clean inlet filter screen per chapter 6.2
,
page
.
,
page 32 and clear any
debris out of shower heads, faucet aerators and whole house
filters.
4. In areas where water has a high mineral content, periodic
descaling may be necessary. See chapter 6.3
,
page 32 for
directions.
Cold water temperature sensor 1. Check connector on wires coming from top of watervalve for a
fault.
secure connection. See Fig. 64, page 49.
2. Sensor may trip if water temperature drops below freezing to
protect heater from freezing conditions Any damage due to
freezing conditions is not covered under warranty.
Backflow temperature sensor over 1. Check combustion air and backflow vent piping for blockage.
309°F. 2. Check if secondary fan connections are disconnected.
The appliance will close the burner 3. Check venting specifications are met. Long vent lengths,
and lock.
venting with more than three elbows, blocked vent or combination
venting may cause this failure.
4. Check sensor resistance (see Fig. 62 page 47).
,
Overheat sensor (ECO) open 1. Disconnect power supply cord and check wire connections on
circuit (should reset when cooler overheat sensor (top right of heat exchanger) and the two
temperatures are detected).
connectors on the control board. See Fig. 64, page 49.
2. Check white wire connections at overheat sensor. Clean
terminals with an eraser. If badly corroded, replace sensor and
wire harness.
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. Clean inlet filter screen and clear any debris out of shower
heads, faucet aerators and whole house filters.
5. In areas where water has a high mineral content, periodic
descaling may necessary, see chapter 6.3
.
6. 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.
Table 20
* By installer or service technician only.
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Problem solving
Display
Cause
Solution
No flame ionization detected with 1. Verify that all manual gas shut off valves are open.
water flow.
2. Check gas type, see Fig. 2, page 6.
3. Reset error code and open a water tap to cycle the heater in an
effort to purge air on new installations. Cycling hot water tap on
and off multiple times may be necessary. If heater still faults with
EA error code, have a licensed gas technician properly purge air
out of the gas line leading to the water heater.
4. Check three wire connections to ignition group on the lower
front of the heat exchanger are secure.
5. Check gas pressure, see chapter 3.12 page 27.
,
6. Check venting specifications are met. Improper venting may
cause premature failure of the flame sensor rod.
7. Check that the minimum power fan speed has been adjusted to
the proper value. See page 18.
8. Observe inside the viewing window of the heat exchanger when
a hot water tap is opened. Sparking should be followed by a
steady blue flame. If flame is unstable or yellow with proper gas
pressure, confirm CO2 readings per section 6.4
.
Ionization failure during operation.
1. Check gas type, see Fig. 2 page 6
,
.
2. Check three wire connections to ignition group on the lower
front of the heat exchanger are secure.
3. Check venting specifications are met. Improper venting may
cause unstable burner flames and loss of flame ionization.
4. Check that the minimum power fan speed has been adjusted to
the proper value. See page 18.
5. Check gas pressure, see section 3.12 page 27.
,
6. Check and adjust CO2 readings, see section 6.4, page 33.
Ionization error at standby.
1. Loose connection to the flame ionization rod. Verify that the
thinner wire leading from the control unit is securely connected to
the flame sensor located on the lower front of the heat exchanger.
See Fig. 64, page 49.
2. Flame ionization rod or control unit may be damaged. Contact
Bosch Water Heating for further instruction.
Gas leakage error, gas valve circuit 1. Disconnect power supply cord and check wire connections on
not closing properly.
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 0.65 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 instruction.
Table 20
* By installer or service technician only.
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Electrical diagram
9
Electrical diagram
16
15
13
12
E
PS
20
M
M
M
11
10
19
T=104°C
T=220°F
9
18
T=110°C
T=230°F
8
FS
7
6
Casc.
input
5
Casc.
output
Back flow
4
3
2
1
17
16
...
1
20
...
1
21
JP2
14
JP8
JP6
JP7
JP5
22
6720608542-04.1AL
Fig. 59 Electrical scheme
1
Intlet water temperature sensor
Outlet water temperature sensor
Backflow temperature sensor
Cascading output connection
Cascading input connection
Ionization sensor
2
3
4
5
6
7
Water flow sensor
Flue gas limiter
8
9
Heat exchanger overheat sensor (ECO)
Gas valve
10
11
12
13
14
15
16
17
18
19
20
21
22
Jumper resistance
Water valve
Primary fan
ON/OFF switch
Secondary fan
AC plug
Main connection
Ignition electrodes
Ground post
Antifreeze kit connection
Fuse
Fuse
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Sensor resistance charts
10 Sensor resistance charts
Outlet temperature sensor characteristics
110
10 5
10 0
9 5
9 0
8 5
8 0
75
70
6 5
6 0
55
50
4 5
4 0
3 5
3 0
2 5
2 0
15
2 2 2
2 17
2 12
2 0 7
2 0 2
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
9 7
9 2
8 7
8 2
77
72
6 7
6 2
57
52
10
4 7
4 2
3 7
3 2
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. 60
Inlet temperature sensor characteristics
12 0
2 4 7
2 4 2
115
110
10 5
10 0
9 5
9 0
8 5
8 0
75
70
6 5
6 0
55
50
4 5
4 0
3 5
3 0
2 5
2 0
15
2 3 7
2 3 2
2 2 7
2 2 2
2 17
2 12
2 0 7
2 0 2
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
9 7
9 2
8 7
8 2
77
72
6 7
6 2
57
52
4 7
4 2
3 7
3 2
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. 61
46
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Sensor resistance charts
Back Flow characteristics
155
150
14 5
14 0
13 5
13 0
12 5
12 0
302
297
292
287
282
277
272
267
262
257
252
247
242
237
232
227
222
217
212
207
202
197
192
187
182
177
172
167
162
157
152
147
142
137
132
127
122
117
112
107
102
97
115
110
10 5
10 0
9 5
9 0
8 5
8 0
75
70
6 5
6 0
55
50
4 5
4 0
3 5
3 0
2 5
2 0
15
92
87
82
77
72
67
62
57
52
47
42
37
32
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. 62
47
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GWH 2700 ES Functional scheme
11 GWH 2700 ES Functional scheme
Fig. 63 Functional scheme
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Interior components diagram and parts list
12 Interior components diagram and parts list
12.1 Interior components
Fig. 64 Components
1
Flue gas collector
Heat exchanger
Flame sensor
12
13
14
15
16
17
18
19
20
21
Ignition electrodes
Observation window
2
3
Backflow temperature sensor
Secondary air fan
4
Primary fan (Mixer)
Outlet temperature sensor
LCD display
5
Gas valve
Water valve with engine and temperature sensor
6
7
On/Off button
Reset button
Control unit
Up button
Down button
LED
8
9
Program key
Flue gas limiter
Heat exchanger overheat sensor (ECO)
10
11
49
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Interior components diagram and parts list
Fig. 65 Appliance overview
50
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Interior components diagram and parts list
12.2 Components diagram
12.2.1 Group 1
9
16
9
15
12
9
17
15
13
14
10
5
6
8
9
7
3
11
4
2
1
6720902973.AA JF
Fig. 66 Components Diagram
Item
10
Description
Reference
Item
Description
Front cover
Reference
8 705 431 286
8 705 506 862
8 701 103 140
8 703 401 170
8 700 506 300
8 704 701 084
8 705 600 003
8 708 104 103
8 703 403 012
Combustion cover clip
Grommet set
8 701 201 032
8 710 203 039
8 705 504 162
8 700 103 710
8 708 006 022
8 700 103 166
8 705 504 116
8 701 309 164
1
2
3
4
5
6
7
8
9
11
Cover shield
12
Exhaust accessory
Gasket exhaust
Inlet air cover
Trade mark badge
Cover screw
13
14
Combustion cover
Combustion cover gasket
Observation window
Holding bracket
Screw
15
Inlet air gasket
16
Inlet air accessory
Mounting bracket
17
Table 21
Table 21
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Interior components diagram and parts list
12.2.2 Group 2
3
2
1
5
4
8
9
6
7
6720902974.AA JF
Fig. 67 Components Diagram
Item
Description
Site window
Reference
Item
Description
Reference
8 705 406 422
8 704 701 052
8 705 700 153
8 707 206 204
8 704 701 054
6
7
8
9
8 701 000 401
8 701 302 249
8 700 205 147
8 710 303 027
1
2
3
4
5
Heat exchanger
Ignition group
Heat exchanger top gasket
Flue gas collector
Heat exchanger O-ring
Rubber grommet
Overheat sensor (ECO)
Heat exchanger bottom gasket
Table 22
Table 22
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Interior components diagram and parts list
12.2.3 Group 3
5
1
2
4
3
6
9
16
13
8
12
11
7
15
14
17
6720902975.AA JF
Fig. 68 Components Diagram
Item Description
Reference
Item Description
Reference
8 708 120 699
8 704 701 087
8 707 204 071
8 707 206 459
8 704 701 097
2 915 011 006
8 707 204 094
8 707 204 072
8 703 403 012
8 705 700 170
10
11
12
13
14
15
16
17
Air duct O-ring
Venturi
8 700 205 149
8 700 306 226
8 700 205 224
8 704 701 059
2 910 642 150
8 701 004 049
8 705 700 155
2 910 952 122
1
2
3
4
5
6
7
7
8
9
Main burner
Burner gasket
Primary fan
O-ring
Mixer / Fan gasket
Screw
Backflow temperature sensor
Washer
Plate gasket
Air supply duct
Screw
Fan mount nut
Secondary fan - NG
Secondary fan - LPG
Screw
Table 23
Gas / Air Mixer
Table 23
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Interior components diagram and parts list
12.2.4 Group 4
14
11
10
13
12
11
6
7
9
1
8
5
2
3
4
6720608158-73.1AL
Fig. 69 Components Diagram
Item
8
Description
Reference
Item
Description
Gas valve
Reference
8 707 021 019
8 703 404 219
8 700 203 041
8 700 703 136
8 703 300 041
8 700 715 389
8 700 103 014
Gas filter
8 700 507 002
8 704 701 085
8 705 202 140
8 704 701 062
8 703 404 220
8 700 205 009
2 910 149 181
1
2
3
4
5
6
7
9
Gasket
Pressure tapping
Washer
10
11
12
13
14
Gas / Fan connector
Washer
Pressure balance tube
Pressure balance nut
Gas supply pipe
Gas valve washer
Regulation screw
O-ring
Screw
Table 24
Table 24
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Interior components diagram and parts list
12.2.5 Group 5
Fig. 70 Components Diagram
Item Description
Reference
Item Description
Reference
8 708 505 024
8 700 205 147
8 700 715 394
8 701 201 028
8 700 715 469
8 700 400 015
8 703 305 349
8 710 103 045
8 701 300 025
10
Inlet fitting with filter
8 703 305 356
1
2
3
4
5
6
7
8
9
Water valve with engine
O-ring
11
12
13
14
15
O-ring
8 700 205 157
8 716 102 607
8 700 507 059
8 700 103 764
8 700 205 231
Cold water pipe
Pipe connection clip
Hot water pipe
Watervalve clip
Water filter
Washer
Temperature sensor
Outlet fitting
O-ring
Table 25
Inlet / Outlet washer
Wireform spring
Table 25
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Interior components diagram and parts list
12.2.6 Group 6
4
8
5
6
7
9
10
11
3
2
1
14
15
16
12
13
6720902978.AA JF
Fig. 71 Components Diagram
Item Description
Reference
Item Description
Reference
8 707 207 257
1 904 521 342
8 700 609 008
8 704 401 371
8 704 401 378
8 704 401 347
8 704 401 348
8 704 401 376
9
Electrode cables
Flue gas limiter
8 704 401 346
8 700 400 032
7 709 003 617
7 709 003 665
8 707 207 153
8 700 201 012
8 703 401 109
8 708 300 123
1
2
3
4
5
6
7
8
Control unit
10
11
12
13
14
15
16
Fuse T2.5A
Cascading kit (optional)
Anti freeze kit
Fuse T1.6A
Power supply cables
Power supply cord
Fan cables
Remote control (optional)
Shaped seal (optional)
Screw (optional)
Wire harness
Jumper
Printed circuit transceiver (optional)
Table 26
Table 26
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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.
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Limited Warranty
14 Limited Warranty
General
Service Labor Costs
Aquastar water heaters are warranted by the
Manufacturer
Thermotechnology Corp..
This warranty does not cover any labor costs
associated with service, removal or re-installation of
part(s). All such costs must be borne by the Purchaser.
Additionally, this warranty does not cover any labor
costs associated with service, removal, installation or
re-installation of the original water heater or a replaced
water heater.
(BOSCH)
through
Bosch
Bosch thermotechnology corporation will furnish a
replacement heat exchanger and will furnish a
replacement of any other part which fails in normal use
and service within the applicable periods specified
below, in accordance with the terms of this warranty.
The Bosch Thermotechnology Corp. replacement will
be warranted for the unexpired portion of the original
warranty. This warranty will be valid only for water
heaters in possession of the original purchaser as
recorded on the warranty card.
NOTE: the water heater must be free of
damaging scale deposits and not subject
i
to gas pressures greater than those
shown on the rating plate, which must not
be altered, defaced or removed.
The Heat Exchanger
How to Make a Claim
If the heat exchanger fails within twelve (12) years after
the original installation and operation, Bosch
Thermotechnology Corp. will furnish a replacement
heat exchanger. However, if the water heater is used
within an approved hot water recirculation and supplied
with circulated water, this heat exchanger warranty is
limited to three (3) years from date of original installation
and operation. If the water heater is installed in other
than a single family dwelling, this heat exchanger
warranty is limited to two (2) years from date of original
installation and operation.
Any claim for warranty parts should be made to your
local dealer or distributor:
BOSCH THERMOTECHNOLOGY CORP.
340 Mad River Park
Waitsfield, VT 05673
TEL. 800-642-3111
In most cases, the dealer or distributor will be able to
promptly honor your claim and subsequently notify
Bosch Thermotechnology Corp.. However, all
replacements are made subject to validation by Bosch
Thermotechnology Corp. of in-warranty coverage. The
damaged or defective item must be made available in
exchange for the replacement.
Exceptions
This warranty will not apply:
• 1. to defects or malfunctions resulting from failure to
properly install, operate or maintain the unit in
accordance with the printed instructions provided;
Miscellaneous
• 2. to damage or abuse, accident, neglect or freezing
and other acts of nature;
No one is authorized to make any other warranties on
behalf of Bosch Thermotechnology Corp.. It is
expressly understood that the replacement warranty of
Bosch Thermotechnology Corp. shall be in lieu of any
and all other warranties, express or implied, including
warranties of merchantability or fitness for a particular
use or purpose, and further that Bosch
Thermotechnology Corp. shall not be liable for any loss
or damage directly or indirectly arising from the use of
the hot water heater, or for any consequential damages
arising from such use (including damages from water
leakage). Bosch Thermotechnology Corp. sole liability
with respect to any defect shall be for the replacement
of the defective part(s). Some states do not allow such
limitations and exclusions, so the above may not apply
to you.
• 3. to damage resulting from operation with either the
flame sensor rod or overheat sensor removed;
• 4. to failure of the heat exchanger resulting from the
operation of the water heater in a corrosive
atmosphere or at water temperatures exceeding the
maximum rating, or if the water heater is not supplied
with potable water;
• 5. to defects or damage cause by any attachment
or modification, including any energy-saving device.
• 6. to damage resulting from scale deposits and/or
highly mineralized / unsoftened water supply.
All Other Parts
If any other part fails within five (5) years after original
installation and operation, Bosch Thermotechnology
Corp. will furnish a replacement part free of charge.
This warranty gives specific legal rights. You may also
have other rights which vary from state to state.
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Limited Warranty
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6720608542
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*
Building Water Pressure
Installing Company
Installer name
Static__________
__________
Operating__________
Range if on Well system __________
_____________________________________________
_____________________________________________
_____________________________________________
_____________________________________________
Address
Phone
* See Chapter 3.12, page 27 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
Bosch Termotecnologia SA
Londonderry, NH 03053
Estrada de Cacia
Tel. 866-330-2730
3801 - 856 Aveiro - PORTUGAL
© 2009 Bosch Thermotechnology Corp.,
Londonderry, NH all rights reserved
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