Bosch GWH 715 ES User manual

GWH 715 ES
(GWH 715 CTDR EFS)
Temperature Modulated with Electronic Ignition
Suitable for heating potable water only - Not approved for space heating purposes
(Intended for variable flow applications)
GWH 715 ES - Natural Gas
GWH 715 ES - Liquefied Petroleum (LP) Gas
6 720 608 158 US (2007.01) AL
Warning: If the information in this manual is not
followed exactly, a fire or explosion may result
causing property damage, personal injury or death.
Do not store or use gasoline or other flammable
vapors and liquids in the vicinity of this or any other
appliance.
Improper installation, adjustment, alteration,
service or maintenance can cause injury or
property damage. Refer to this manual. For
assistance or additional information consult a
qualified installer, service agency or the gas
supplier.
In the Commonwealth of Massachusetts this
product must be installed by a licensed plumber or
gas fitter.
Upon completion of the installation, these
instructions should be handed to the user of the
appliance for future reference.
What to do if you smell gas
• Close gas valve. Open windows.
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any
phone in your building.
• Immediately call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire
department.
• Installation and service must be performed by a
qualified installer, service agency or the gas supplier.

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Index
Index
1Warning 3
2 Appliance details 4
2.1 Features 4
2.2 GWH 715 ES Specifications (Technical data) 4
2.3 Unpacking the GWH 715 ES heater 5
2.4 General rules to follow for safe operation 6
2.5 Dimensions and Minimum installation
clearances 7
3 Installation instructions 8
3.1 Tools required for installation 8
3.2 Introduction 8
3.3 Proper location for installing your heater 8
3.4 Heater placement and clearances 8
3.5 Mounting installation 8
3.6 Gas piping & connections 10
3.7 Water connections 12
3.8 Water quality 12
3.9 Recirculation application 13
3.10 Combustion air requirements 13
3.11 Venting 15
3.12 Measuring gas pressure 24
4 Electrical connections 25
4.1 Electrical power supply 25
4.2 Position of the fuses in control unit 25
5 Operation instructions 26
5.1 Description LCD display 26
5.2 For your safety read before operating
your water heater 27
5.3 Power 27
5.4 Temperature selection 27
5.5 Use of optional remote control accessory
(part no. TSTAT2) 28
5.6 Operation 28
5.7 Reset button 28
5.8 Program button 28
5.9 Locked condition 28
6 Maintenance and service 29
6.1 Annual maintenance 29
6.2 Winterizing for seasonal use 29
6.3 Mineral scale build-up 30
6.4 Adjusting CO2 30
6.5 Program values 33
6.6 Control board diagnostics 34
7 Troubleshooting 35
7.1 Introduction 35
7.2 Burner do not ignite when hot water
is turned ON 35
7.3 Water is too hot 35
7.4 Water is not hot enough 35
7.5 Low water flow/pressure 36
7.6 Hot water temperature fluctuates at tap 36
7.7 Noisy burner/heater during operation 36
8 Problem solving 38
8.1 Error code diagnostics 38
9 Electrical diagram 42
10 Sensor resistance charts 43
11 GWH 715 ES Functional scheme 45
12 Interior components diagram
and parts list 46
12.1 Interior components 46
12.2 Components diagram 48
13 Protecting the environment 54
14 Limited Warranty 55

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Warning
3
1 Warning
For your safety
Do not store or use gasoline or other flammable,
combustible or corrosive vapors and liquids in the
vicinity of this or any other appliance.
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.
Fig. 1
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
monoxide poisoning or fire.
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: Place the heater in a location
where water leaks will do NO DAMAGE
to adjacent areas or lower floors.
Warning: Field wiring connections and
electrical grounding must comply with
local codes, or in the absence of local
codes, with the latest edition of the
National Electric Code, ANSI/NFPA 70,
or in Canada, all electrical wiring must
comply with the local codes and the
Canadian Electrical Code, CSA C22.1
Part 1.
Warning: Shock hazard: line voltage is
present. Before servicing the water
heater, unplug power supply cord from
outlet. Failure to do so could result in
severe personal injury or death.
Warning: The heater must be
disconnected from the gas supply
piping system during any pressure
testing of that system at test pressures
equal to or more than 0.5 psig.

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Appliance details
2 Appliance details
2.1 Features
Parts
• Key Pad interface control
• High power pre-mix compact burner with low NOx
emissions
• Modulating Gas Valve with constant gas:air ratio
control
• Modulating water valve for improved comfort and
temperature control.
High quality materials for long working life
• Copper heat exchanger
• High efficiency Ceramat Burner
• 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
• Program button (Selectable temperature default)
• Failure codes for easy diagnostics and repair
• Easily removable one-piece cover.
Accessories (Bosch part #)
• Optional wireless remote control accessory to
operate with the appliance (TSTAT2)
• Cascading kit (TLINK)
•Outdoorkit(PTOK)
• External water filter (8703305356).
2.2 GWH 715 ES Specifications
(Technical data)
Approved in US/Canada
Capacity
Maximum flow rate: 7.3 GPM (27 l/min) at a 45°F
(25°C) rise.
Maximum output
160,500 Btu/h (47.0 kW)
Maximum input
199,000 Btu/h (58.3 kW)
Efficiency in %
Thermal efficiency > 82%
Min. Input
19,900 Btu/h (5.8 kW)
Temperature Control
Selection range: 100°F (38°C) - 140°F (60°C)
Default temperature: 122°F (50°C)
Stability: +/- 2°F (+/- 1°C)
Gas Requirement
Gas connection (inches) - ¾”
Inlet gas pressure under operation (with a high hot
water flow rate)*
• Propane: 9” - 14” water column
• Natural Gas: 4” - 14” water column.
* To measure gas pressure, see Measuring Gas
Pressure, chapter 3.12, page 24.
Water
• Hot water connection (inches) - ¾”
• Cold water connection (inches) - ¾”
• Water valve material: Polymer (PPS) (Polypropylene
Sulfid)
• 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 (2.5 - 6.1 l/m).
• Minimum recommended water pressure: 30 PSI
(2.07 bar).
• Minimum well pressure 40 psi, see page 12.
• Connections:
– Bottom of heater
iBOSCH is constantly improving its
products, therefore specifications are
subject to change without prior notice.

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Appliance details
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Combustion
•NOx≤55 ppm
•CO≤190 ppm
•CO
2level set from factory, see chapter 6.4, page 30.
Dimensions
• Depth (in): 11¼” (286 mm)
• Width (in): 17 7/8” (452 mm)
• Height (in): 30½” (775 mm)
• Weight: 67 pounds (30.5 kg).
Gas types
Natural Gas.
LP Gas.
Voltage
120 V AC (60 Hz) nominal
Amperage
Idle - 40 mA
Operation - ≤2.5 A
Noise
45 - 65 db (A)
Safety devices
• Flame failure device (ionization flame rod sensor)
• Pressure relief valve (supplied with heater)
• Over heat prevention (temperature limiter)
• Inlet temperature sensor
• Outlet temperature sensor
• Back flow temperature sensor.
Water protection
IP X4 (protection against water drops)
2.3 Unpacking the GWH 715 ES heater
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. 2 Rating plate
ASerial number
BType of gas
The box includes:
• GWH 715 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.boschpro.com)
• Product registration card
• Energy Guide label.
Please complete and return the enclosed product
registration card.
The GWH 715 ES is not approved or designed for:
• Manufactured (mobile) homes, boats or any
mobile installation.
• Use above 4500ft A.S.L. altitude.
• Outdoor installation without installation of
Outdoor kit (PTOK).
• Applications where inlet water temperature is
higher than 140ºF (60°C). A 3-way valve or
mixing valve must be installed before the
appliance if inlet water temperature exceeds
this limit.
• Space heating purposes.
iIf appliance is installed at elevations
between 2000ft and 4500ft, a
combustion gas analyzer is required for
proper calibration of appliance. (see page
24).

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Appliance details
To remove front cover
BLoosen the two Philips head screws located on
bottom rear of cover (see Fig. 3).
Fig. 3 Loosen the two screws
BLift front cover panel upward and remove.
Fig. 4 Remove the front cover
To remove combustion cover (service only)
BOpen the four clips and remove the combustion
cover see Fig. 5.
Fig. 5 Remove the combustion cover
2.4 General rules to follow for safe
operation
B1. 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.
B2. 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.
B3. 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 3.11 (page 15). 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 3.3, page 8 and 3.10,
page 13.
B4. You must vent your heater. See chapter 3.11, page
15 on VENTING.
B5. 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).
B6. Keep water heater area clear and free from
combustibles and flammable liquids. Do not locate
the heater over any material which might burn.
B7. Correct gas pressure is critical for the proper
operation of this heater. Gas piping must be sized to
provide the required pressure at the maximum output
of the heater, while all the other gas appliances are in
operation. Check with your local gas supplier, and
see the section on connecting the gas supply, see
chapter 3.6.
B8. 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.
B9. 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.
B10. Failure to install heater correctly may lead to
unsafe operation and void the warranty.

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Appliance details
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2.5 Dimensions and Minimum installation clearances
Fig. 6 Dimensions
1On/Off button
2Reset button
3Program key
4Power ON or stand-by LED
5LCD display
6Up button
7Down button
Fig. 7 Minimum clearances
Note: For servicing access, a 2ft clearance to front
cover is recommended.
Note: Vent clearances vary per manufacturer. Consult
vent manufacturer for specific clearance information.
Model GWH 715 ES
TOP (A) 12”
FRONT (B) 1”
BACK 0”
SIDES 1”
FLOOR (C) 12”
VENT DIAMETER 3”
VENT CLEARANCES 1”
Table 1 Minimum clearances

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Installation instructions
3 Installation instructions
3.1 Tools required for installation
• Philips head screwdriver
• Flat head screwdriver
• Adjustable wrench
• Level
• Thermometer
• Standard plumbing tools
•Manometer.
3.2 Introduction
Please follow these instructions. Failure to follow
instructions may result in:
BDamage or injury.
BImproper operation.
BLoss of warranty.
If you are unable to perform the tasks required to install
this heater properly, please contact a locally licensed
plumber or gas technician.
3.3 Proper location for installing your
heater
Carefully select the location of the water heater. For
your safety and for proper heater operation, you must
provide combustion air to the heater and a proper
exhaust vent system.
Follow the guidelines below:
B1. Locate the heater where venting, gas and
plumbing connections are feasible and convenient.
B2. 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.
3.4 Heater placement and clearances
The GWH 715 ES is approved for installation on a
combustible wall (see chapter 3.5 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 listed
below. See also Fig. 7.
A. Top 12 inches (306 mm)
B. Front 1 inches (25 mm)
C. Back 0 inches
D. Sides 1 inches (25 mm)
E. Bottom 12 inches (306 mm)
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 3.11 (page 15) Venting.
3.5 Mounting installation
Warning: The water in this water
heater is cold and always remains cold
except for the times the burner is on. In
the event of power outage in
conjunction with freezing temperatures,
it is recommended that the heater be
drained.
See chapter 6.2, page 29 “Winterizing”
for draining instructions.
Warning: Flammable materials,
gasoline, pressurized containers, or any
other items or articles that are potential
fire hazards must NOT be placed on or
adjacent to the heater. The appliance
area must be kept free of all
combustible materials, gasoline and
other flammable vapors and liquids.
Warning: before starting
installation
BCheck that there are no loose parts
inside the appliance
BConfirm the gas type of the heater
matches the gas supply you will be
connecting the heater, see Fig. 2,
page 5.
BEnsure that gas pipe, gas valve,
mixer, fans and burner have no
damage and are properly fitted.
iFront cover should be removed (see
instructions on page 6) in order to inspect
components visually.
Warning: Do not install this appliance
on a carpeted wall. The heater must be
mounted on a wall using appropriate
anchoring materials.

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Installation instructions
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If wall is sheathed with plaster or drywall, it is
recommended that two support boards, either 1”x4” or
1/2" (minimum) plywood first be attached across a pair
of studs, see Fig. 8, page 9.
BSecure the wall mounting bracket provided with the
heater to the wall surface. The heater must be kept
level on the wall surface, see Fig. 9, page 9.
BHang the appliance on the bracket, see Fig. 10, page
9.
Fig. 8 Distance between support boards
Fig. 9 Leveling the mounting bracket on the studs
Fig. 10 Mounting the heater
Studs 16"
(406mm) on
center Warning: Appliance must be installed
vertically.

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Installation instructions
3.6 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.
GAS CONNECTIONS
BInstall a manual gas shut off valve on the gas supply
line.
BInstall a union when connecting gas supply.
BThe minimum internal diameter required for
any appliance connector is ¾”, see Fig. 13 for
more details on pipe sizing.
BNational Fuel Gas Code requires that a sediment
trap (drip leg) be installed on gas appliances not so
equipped. The drip leg must be accessible and not
subject to freezing conditions. Install in accordance
with the recommendations of the serving gas
supplier, see Fig. 11.
Fig. 11 Gas connection (drip leg)
Once connections are made, check for gas leaks at all
joints. Apply some gas leak detection solution to all gas
fittings. Bubbles are a sign of a leak. A combustible gas
detector may also be used to detect for leaks.
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. 13, page 11 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 24 for the procedure to confirm gas pressure.
Proper gas pressure must be confirmed at time of
installation.
Fig. 12
Warning: DO NOT connect to an
unregulated or high pressure propane
line or to a high pressure commercial
natural gas line.
Warning: The heater must be isolated
from the gas supply piping system
during any pressure testing of that
system at test pressures equal to or
more than 0.5 psig. If overpressure has
occurred, such as through improper
testing of the gas lines or malfunction of
the supply system, the gas valve must
be checked for safe operation.
Gas supply
Cap
Minimum
3”
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 piping
Inlet gas particle screen
(included)