Bosch WR430-7K Assembly instructions

6 720 606 599 CA (03.11) AL
Model
WR430-7K
• installation
• operation
• maintenance
The Bosch instantaneous water heater is a high efficienc ,
space saving answer to our water heating needs. All Bosch
instantaneous water heaters heat water onl as required;
no energ is lost maintaining a large volume of water at
elevated temperatures as in tank-t pe storage water heaters.
Suitable for heating potable water onl . Not approved for
space heating purposes.
POWER VENTED - E ECTRONIC IGNITION
ASTRAVAN DISTRIBUTORS, TD.
123 Charles Street
North Vancouver, B.C. V7H 1S1
Phone Canada: [phone]
Phone USA: [phone]
Web Site: www astravan.com
Note: In case of problems please contact your salesman or installer
NOTICE TO INSTA ER: Please leave this
manual with the owner or affix adjacent to
appliance.
Instantaneous gas water heater
WARNING: If the information in this
manual is not followed exactly, a fire or
explosion may result causing property
damge, personal injury or death.
- Do not store or use gasoline or other
flammable vapors and liquids in the vicinity of
this or any other applicance
- WHAT TO DO IF YOU SME GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not
use any phone in your building.
• Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.
• If you cannot reach your gas supplier, call
the fire department.
- Installation and service must be performed by
a qualified installer, service agency or the gas
supplier.
READ INSTRUCTIONS CAREFU Y BEFORE INSTA ING

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Water Connection 1/2” Thread fitting
H x W x D 29 3/4” x 18 1/4” x 8 3/4”
Vent 4” (Categor III Gas Appliance)
Max. lineal vent pipe length 15" (4.5m)
Gas Connection 1/2” NPT thread
Minimum recommended house suppl pressure 40 Psi
Warm position minimum water pressure 18 psi (no fittings)
Hot position minimum water pressure13 psi (no fittings)
Max. Water Pressure 150 Psi
Shipping Weight 55 Lbs
Net Weight 44 LB
2.5 GPM at 90° rise (32°C) (9.5 l)
5.0 GPM at 45° rise (16°C) (19.5 l)
Min. Water Flow 1/2 gal/min
120V/60Hz 1.2 Amps
LP GAS Suppl Pressure inlet. min. 11”W.C.*
LP GAS regulator outlet pressure 9.9”W.C.*
Natural Gas Pressure inlet min.: 7”W.C.*
Natural Gas Regulator Pressure 5.38 W.C.**
* Inlet gas pressure must not exceed this value
** For purposes of input adjustment
ELECTRICAL 3 ft. ( 0.9 m) power cable supplied c/w CSA
3 prong plug.
UNPACKING THE BOSCH WR430-7K HEATER
This heater is packed securel . The box includes two water connection fittings, a control knob, a gas pressure regulator, a
pressure relief valve, an incandescent particle tra , two hooks for hanging the heater, this manual. Do not lose this manual
as there is a charge for replacement.
BOSCH WR430-7K
Principle of Operation:
When a hot water faucet is opened, the flow of water through
the heater causes the gas valve to open. At the same time
a microswitch is activated which sends a spark to the pilot.
The flame sensor confirms that the pilot has been lighted
and allows burners to ignite. The pilot goes out. The power
exhaust s stem runs as long as the burners are on. The
heat exchanger coils absorb the heat generated b the
burners and transfer heat to the water. When the hot water
faucet is shut off, the gas valve automaticall closes and
the burners turn off, followed immediatel b the exhaust
s stem. Your hot water faucet is an ignition ke to turn on
the water heater, giving ou control over our hot water energ
use. Ever time ou turn off our hot water faucet, the energ
consumption for hot water returns to zero.
FEATURES
- Power Venting with safet shutoff
- Electronic Pilot Ignition
- On/Off switch to activate s stem
- High Qualit Materials for Long Working Life.
- Copper heating coils for endless suppl of hot water.
- Burner output proportional to hot water flow demand for
maximum energ efficienc .
- Safet flame sensor at pilot burner.
- Automatic over heating protection shut-off sensor.
- Stainless steel burners with stabilized blue flame.
- Built-in corrosion resistant power venter.
- Compact space saver: mounts on a wall with two hooks.
- Easil removable one-piece cover.
- Eas one person installation.
- Adjustable water flow restrictor ensure that water flow
demand will not exceed the heating capacit of the heater.
NAT. GAS PROPANE
max. 130 000 Btu/hr 125 000 Btu/hr
Gas Input min. 28 000 Btu/hr 28 000 Btu/hr

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DIMENSIONS
Figure 1
Maximum H drostatic water pressure - 1.03 MPa (150 p.s.i.)
Maximum recommended working pressure - 0.69 MPa (100 p.s.i.)
Minimum working pressure - 0.09 MPa (13 p.s.i.) no piping attached
Reccomended pressure for showers and domestic, 0.27 MPa (40 p.s.i.)
• The high altitude ratings listed are Canadian Gas Association high altitude ratings and are valid onl in Canada. In the U.S., the
National Fuel Gas Code, ANSI Z223.1-1988, recommends for high altitude installations above 2,000 feet, that the input rate be
reduced 4% for each 1,000 feet above sea level. - See page 15.
EXTERIOR
TERMINATION
Model T pe of Gas Altitude Input
Size, mm Qt.
natural gas 130 000 Btu/hr (38 kW) 1.20 diam. 18
propane/LP 125 000 Btu/hr (36.6 kW) 0.79 diam. 18
natural gas 117 000 Btu/hr (34.3 kW) 1.20 diam. 18
propane/LP 112 000 Btu/hr (32.8 kW) 0.79 diam. 18
WR430-7.K..
standard
(0 - 2 000 ft)
high *
(2 000 - 4 500 ft)
Main Burner Orifices

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FORWARD
The design of the WR430-7K complies with CAN 1-4.3
and ANSI Z21.10 (latest edition) as an instantaneous gas
water heater. In addition, the WR430-7K also complies with
CAN 1-2.17 for use at high altitudes, 2,000 - 4,500 ft. above
sea level.
Installation, operation and maintenance instructions are
provided in this manual. Installation and operation
instructions should be thoroughl reviewed before
proceeding with installation of the BOSCH instantaneous
gas water heater.
Note: Proper plumbing, venting, gas connections and an
adequate suppl of combustion air are required for
safe and reliable operation. Abilit equivalent to that
of a licensed tradesman in the field involved is
required for installation and/or service of these water
heaters.
OCATION
Before installing the BOSCH instantaneous gas water
heater, consideration must be given to proper location. The
location should be as close to outside vent termination as
practicable, in an area with an adequate air suppl and as
centralized with the piping s stem as possible. The heater
should not be located in an area where it will be subject to
freezing. The heater should be located in an area where
leakage of the heater or its connections will not result in
damage to the area adjacent to the heater or to lower floors
of the structure. See venting page 6.
Note: When such locations cannot be avoided, it is
recommended that a suitable drain pan, adequatel
drained, be installed under the water heater. The pan
must not restrict combustion air flow.
E ECTRICA
A grounded switched plug receptable must be provided
immediatel below the left hand corner of heater to accept
and provide power to supplied 3 ft. (0.9m) appliance cable
and plug.
INSTA ATION INSTRUCTIONS
The Bosch WR430-7K is a high efficienc fin tube heater and should not be installed and operated during construction or
building renovations if location is exposed to above normal dust levels. This can cause dust build up in the finned heat
exchanger and result in damage to heater and be a hazard to health.
The BOSCH instantaneous gas water heater is designed
to operate on natural or propane gas: however, make sure
that gas on which heater is to operate is the same as
specified on the heater’s model/rating plate.
In addition to these instructions, the water heater shall be
installed in accordance with CAN/CGA-B149 Installation
Code (in Canada) or Z223.1-latest edition, National Fuel
Gas Code (in U.S.A.) and/or local installation codes. These
shall be carefull followed in all cases.
AIR REQUIREMENTS
For safe operation, sufficient air for combustion, ventilation
and dilution of flue gases must be available. An insufficient
suppl of air will result in a ellow luminous burner flame,
causing carboning or sooting of the heat exchanger.
In order to prevent corrosion, make sure that the combustion
air is kept free of aggressive substances. Substances that
especiall contribute to corrosion are halogenated
h drocarbons (e.g., chlorine and fluorine) which are
contaned in solvents, paint, adhesives, propellant gases,
various household cleaners, etc. Take precautionar
measures as necessar .
In unconfined spaces, in buildings of normal construction,
infiltration normall is adequate to provide air for combustion,
ventilation and dilution of flue gases. However, a confined
space must be provided with two permanent openings to
provide combustion and ventilation air to the appliance. Each
opening shall have a free area of one square inch per 1,000
Btu/Hr* of total input rating of all the appliances in the
enclosure. One opening shall be within 12 inches of the
top and one within 12 inches of the bottom of the enclosure.
* Special Note
When the WR430-7K is installed in a confined space of
minimum size the openings described above must be
increased in to a size of 1-1/2 square inches per 1,000
BTU/Hr. In other words, when installed in a minimum sized
confined space the two openings that are to be made in
the enclosure within 12 inches of the top and 12 inches of
the bottom must each have a minimum free area of, (1 -
1½” - 2" x (130) = 195 square inches.

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Expansion and contraction of piping due to changing water
temperature in the pipes imparts movement to the heater
which, if mounted directl to a brittle, friable board, such as
plasterboard, can cause failure of mounting.
For either a confined or unconfined space in a building of
tight construction with inadequate infiltration, air must be
drawn from the outdoors or from spaces that freel
communicate with the outdoors. Two permanent openings
located as indicated are to be provided as follows:
1. When communicating with outdoors directly or by
means of vertical ducts, each opening shall have a
free area of not less than one square inch per 4,000
BTU/Hr. of total input of all appliances in the space.
2. When communicating with outdoors by means of
horizontal ducts, each opening shall have a free area
of not less than one square inch per 2,000 BTU/Hr. of
total input of all appliances in the space.
For detailed requirements see:
• in Canada, CAN/CGA-B149 Installation Codes
• in U.S.A., ANSIZ223.1-latest edition, National Fuel Gas
Code.
WARNING!
1. Flammable materials, gasoline, pressurized containers,
or an other items or articles that are potentiall fire
hazards must never 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.
2. Do not obstruct the flow of combustion and ventilation
air to the appliance.
C EARANCE
The WR430-7K is design certified for installation on a
combustible wall and for installation in an alcove or closet
with minimum clearances to combustible construction of 0
mm from back, 102 mm (4 inches) from sides, 305 mm (12
inches) from top and bottom, and 102 mm (4 inches) from
front. A minimum of 305 mm (12 inches) shall be allowed
for maintenance of serviceable parts. Clearance from vent
is dependent upon the clearance rating of the venting
material used; see venting page 6.
Warning!
Check Flue Gas Safet Device good functioning, please
proceed as explained in "Flue gas safet device" page 16.
THIS APPLIANCE MUST BE INSTALLED IN ACCORDANCE WITH THE NATIONAL FUEL GAS CODE ANSI Z223.1-
latest edition in U.S.A. or CAN/CGA-B149 INSTALLATION CODES IN CANADA. LOCAL CODES AND/OR THE
REQUIREMENTS OF THE AUTHORITY HAVING JURISDICTION MUST BE FOLLOWED.
MOUNTING
The WR430-7K is design certified for mounting to a wall.
The heater must not be installed on a carpeted wall. The
heater must be mounted to the wall using appropriate
anchoring materials.
Note: If wall is a stud wall sheathed with plasterboard it is
recommended that support board(s), either 1 x 4's
or 1/2” (minimum) pl wood first be attached across
a pair of studs and then the heaters should be
attached to the support boards. See Figure 2.
Figure 2
Fig. 2 - Mounting the Heater
WALL STUDS
1” X 4”
SPACE BOARD
SUPPORT BOARD

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Bosch POWER VENTING SYSTEM
INTRODUCTION
Bosch power venting models are designed to overcome difficult venting problems which cannot be performed
with atmospheric venting: to meet our hot water demand load ver efficientl , with an environmentall friendl
appliance which conserves energ and significantl reduces combustion emissions to atmosphere.
GENERA INFORMATION
This Power Vent S stem must be installed b a *qualified installer in accordance with all applicable local gas
and electrical codes and in the absence of:
• With the current CAN1/CGA B149 installation code for gas burning appliances and the Canadian Electrical
code C22.1-M90 part 1 (for Canada).
• With the National Fuel Code and the ANSI Z223.1-LATEST and National Electrical Code ANSI/NFPA No
70-LATEST electrical code (for USA).
The Bosch warrant will be voided b , and Bosch disclaims an responsibilit for the following actions:
• Use of an unapproved venting component part not manufactured or approved b Bosch in combination
with the Bosch WR430-7K unit.
• The Bosch WR430-7K must not be modified in an wa when installing the Power Vent S stem. All
s stems must be installed as per Bosch Installation Guide.
• Installation other than instructed in this manual.
CAUTION:
Bosch Power Vent System must be installed by a qualified agency in accordance with these instructions.
If improperly installed a hazardous condition such as an explosion or Carbon Monoxide poisoning
could result. Bosch will not be responsible for any and all improperly installed appliances.
*QUA IFIED INSTA ING AGENCY: An individual, firm, corporation or compan which either in person or
through a representative is engaged in and is responsible for the installation and operation of gas appliances and
draft control devices, who is experienced in such work, familiar with all precautions required, and has complied
with all the requirements of the authorit having jurisdiction.
GENERA VENTING INFORMATION
SIZING & DISTANCES:
Plan the vent s stem so that code clearances and manufacturer’s distances are maintained from combustible
materials, plumbing and wiring.
This unit ma be directl connected to approved vent termination with a 90° elbow or located with a maximum
lineal length of 15 ft. (4.6m) including two 90° elbows from termination. All vent pipe and fittings must only be
4” (10.2cm) in diameter.

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Bosch POWER VENTING SYSTEM
GENERA VENTING INFORMATION - continued
APPROVED VENTING MATERIA S:
Single wall:
As gauge listed in the current CAN1/CGA B149 installation code for gas burning appliances (for Canada),
National Fuel Code ANSI Z223.1-LATEST (for USA).
Note: Cannot be used in concealed locations.
B-Vent materials:
Straight lengths onl (no elbow) ma be used under following conditions
(i) Unsealed 5” B-vent ma be used as a chase for sealed 4” single wall through concealed or unheated
areas.
Clearances to combustible materials for walls and partitions:
• 1” (25mm) for B-Vent.
• 3” (76mm) for single wall and uninsulated PVS-1 vent piping.
A wall thimble must be installed for internal wall applications.
All runs through unheated space or exposed to outside temperatures must be insulated to prevent condensation.
All portions of the vent s stem under positive pressure during operation (on the outlet side of the WR430-7K)
shall be sealed with high temperature silicone and high temperature aluminum duct tape and installed so as to
prevent leakage of flue or vent gases into building.
GENERA CODE REQUIREMENTS
Before commencing an installation alwa s consult with local gas and electrical codes and authorities, in the
absence must be installed:
• With the current CAN1/CGA B149 installation code for gas burning appliances and the Canadian Electrical
code C22.1-M90 part 1 (for Canada).
• With the National Fuel Code and the ANSI Z223.1-LATEST and National Electrical Code ANSI/NFPA No 70-
LATEST electrical code (for USA).

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Bosch POWER VENTING SYSTEM
VENT TERMINA INSTA ATION:
Before installing Bosch WR430-7K determine the location of vent s stem termination which ma be immediatel
connected with a 90° elbow or with a maximum lineal length of 15 feet including two 90° elbows. (See Fig. 1)
Note: In cold climate areas negative air pressure such as unbalanced heating and ventilating systems can
cause reverse air flows in gas vent and chimney systems. Under extreme cold conditions this can cause
freezing and damage Bosch heat exchanger during prolonged period of times when they are not in use,
such as night time hours. Vent termination with back draft flapper is supplied in order to minimize outside
air infiltration and risk of freezing equipment.
The approved terminal shall be so arranged for flue gases to be directed in a manner which will not jeopardize
people, overheat combustible structures or enter into buildings, and that proper clearances are maintained (See
Fig. 2 )
a) The vent terminal of this Power Vent S stem shall not be less than 7 feet (213cm) above grade when
located in areas accessible to public walkwa s.
b) A vent terminal shall terminate at least 3 feet (91cm) above and a minimum of 10 feet (305cm) horizontall
from an (mechanical) air inlet.
c) The vent terminal shall not be within 6 feet (183cm) radius from a gas meter or regulator, and horizontall
it must be a minimum of 3 feet (91cm) from the centre line of such regulator.
d) The vent terminal shall be a minimum of 6 feet (182cm) from an combustion air inlet.
e) The vent terminal shall terminate from an opening window, at least 4 feet (122cm) below or below the
opening and 12 inches (30cm) horizontall . From a door 1 foot (30cm) above and 9 inches (23cm)
horizontall .
f) The vent terminal shall not be less than 3 feet (91cm) from an adjacent building.
g) The vent terminal shall not be less than 2 feet (61cm) above grade.
90° el
12 ft straight
(5.7m)
90° el
90° el
90° el
15 ft straight
(4.6m)
3 ft straight
(0.3m)
MAXIMUM ENGTH OF A PIPE ENGTHS
MUST NOT EXCEED 15 FT (4.6M)

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Bosch POWER VENTING SYSTEM
VENT INSTA ATION
1. Choose approved terminal location
2. Cut vent terminal opening through outside wall - Refer to installation instructions supplied with termination.
3. Install vent terminal b fastening from outside with 4 screws and caulking around flange edge. Check that
optional flapper moves freel if applicable.
4. Install 4” venting materials and secure all joints with a minimum of four screws for each joint. Please note that
wherever possible use continual lengths of pipe to reduce the number of joints.
5. Seal all positive vent pipe and elbow joints between Bosch unit and vent terminal with high temperature
silicone and/or hi temperature aluminum tape following manufacturer’s instructions (i.e. alwa s push silicone
ahead of nozzle)
E ECTRICA WIRING:
1. The electrical contact ratings are as follows:
______ 1/10 HP at 120 VAC
______ 3 Amps (full load) at 120 VA
2. Provide switched plug receptacle to accommodate Bosch grounded plug.
3. Make certain the power source is adequate for the fan motor requirements.
Figure 2
REGU ATOR VENT
72”
72”
36” 36”

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Bosch POWER VENTING SYSTEM
VENT INSTA ATION (continued)
6. Support venting duct with plumber’s strap (supplied b installer). Solid piping need onl be supported ever
four feet. All horizontal pipe joints must be secured with a minimum of four screws per joint. (See Figure 3)
7. All runs through unheated spaces must be wrapped and insulated with a minimum of 1” insulation.
OPERATION AND CHECKING THE DRAFT
A. Place Bosch appliance into operation. Follow lighting pilot and operating instructions on Bosch
cover.
1. Draw water continuousl to activate appliance which will turn on gas burner.
2. CHECKING THE DRAFT. Operate the appliance with cover in place for a minimum of five minutes and
check for proper venting, and assure that the combustion products are venting properl , b passing a
lighted match flame or smoke taper over the top edge of the Bosch cover and towards draft hood. If the
vent is drawing properl , the smoke or match flame will be drawn over the top edge of the Bosch cover
and into the draft hood or opening. (see drawing below Checking The Draft)
NOTE: If smoke is not drawn in then the combustion products are
escaping from the relief opening into the room. Under these
conditions, the equipment shall not be operated until proper
adjustments or repairs are made to provide adequate draft.
3. Check draft spill safet switch b obstructing outside vent terminal and b drawing water. Spill switch
should trip and shut off gas suppl to Bosch unit. Remove outside obstruction.
4. If spill switch trips allow 5 minutes to reset.
CHECKING THE DRAFT
Figure 3
Vent support hangers (plumber's
strapping) should be 4 ft. apart on
horizontal runs.
All joints must be sealed with high temperature silicone
and high temperature aluminum vent pipe tape
RIGID PIPE
positive pressure
All clamped joints on the positive
side of the power venter are to
be sealed with high temperature
silicone.
Use 4 screws
per joint

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Bosch POWER VENTING SYSTEM
B. The Air-Flow Adjustment on the Power Venter is factor set for optimum air flow. Operating at its setting will
assure that combustion gases are safel removed to the outside.
MAINTENANCE
Points of inspection are:
1. Motor - Motor must rotate freel .
2. Fan Wheel - Wheel must be clean of dust or an other coating which inhibits rotation or air flow. Remove
all foreign material from vent s stem before operation.
3. Spill Switch - Verif proper spill switch operation b observing Operation Sequence and b temporaril
blocking termination outlet.
4. Check Draft - Check for flue gas spillage following steps in the Operation And Checking Draft on page 9.
5. Vent Termination - Inspect to ensure installation and clearances have not been altered or obstructed and
that the back draft flapper (when used) movement is free and operational. Note that terminal hood is
removable for eas flapper maintenance or replacement.
Hinge
Vent termination hood
Flapper

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DRIP TRAY
If the water heater is being mounted above a floor of
combustible construction the drip tra (shipped loose in the
carton with the water heater) must be attached to the bottom
of the front cover of the water heater at the time of
installation. The drip tra should be attached to the front
cover, using screws provided, as shown in Figure 3.
Failure to use drip tra when installing unit above a floor of
combustible construction will cause an unsafe condition and
possible fire and will be in violation of A.G.A. and C.G.A.
certification of the unit.
Water valve and S-bends, top view
WATER CONNECTIONS
The BOSCH instantaneous water heaters are provided with
two S-bend water connectors/adaptors that must be
connected to inlet and outlet connections on water valve
assembl , see Figure 4, below.
Figure 4
The purpose of the S-bend water connectors/adaptors is to
provide threaded water connections that meet standards
used in North America, ANSI Standard Taper Pipe Thread
(1/2” NPT). The cold water suppl should be connected to
S-bend attached to inlet of water valve and the hot water
connection should be made to S-bend attached to the outlet
of water valve.
If plastic piping is to be used, a 1.5 meter (approx. 5 feet)
length of metal piping must first be attached to both the
cold water inlet and hot water outlet of the water heater.
Note: A shut-off valve should be placed in the cold water
suppl line to the heater to facilitate servicing the
heater.
SCREWS
INCANDESCENT PARTICLE TRAY
Figure 3

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Check to make sure that the gas listed on the rating plate is
same as gas listed on the pressure regulator. See
PRESSURE REGULATION section of this manual for
information regarding gas pressure settings.
Note: Before attaching the gas suppl line, be sure that all
gas pipe is clean on the inside. To trap an dirt or
foreign material in the gas suppl line, a drip leg must
be incorporated in the piping. The drip leg must be
readil accessible and not subject to freezing
conditions. Install in accordance with the
recommendations of serving gas supplier.
Joint compounds (pipe dope) shall be applied sparingl and
onl to the male threads of pipe joints. Do not appl
compound to the first two threads. The joint compound must
be resistant to the action of liquified petroleum gases.
Before placing water heater in operation, check for gas
leakage. Soap and water solution, or other material
acceptable for this purpose shall be used in locating gas
leaks. Matches, candles, lighters, or other ignition sources
shall not be used for this purpose.
WARNING
The heater and its individual shutoff valves must be
disconnected from the gas suppl piping s stem during an
pressure testing of that s stem at test pressures in excess
of 3.45 kPa (1/2 psig).
The water heater, including the pressure regulator provided
with it, must not be operated at gas suppl pressures in
excess of 3.45 kPa (1/2 psig). If overpressure has occurred
such as through improper testing of the gas lines or
emergenc malfunction of the suppl s stem, the gas valve
and regulator must be checked for safe operation. Make
sure that the outside vent valves are protected against
blockage. These are part of the gas suppl s stem, not the
water heater. Vent blockage ma occur during ice storms.
Figure 7 Gas Burner test point D for measuring burner
manifold pressure at full flow and input:
Standard Altitude: 4.58”W.C. Nat Gas, 9.11”W.C. Propane.
High Altitude: 3.73”W.C. Nat Gas, 7.27”W.C. Propane.
GAS CONNECTIONS
Before connecting the gas suppl to the heater, check
heater’s model/rating plate to make sure that the gas on
which heater is to operate is the same as specified on the
model/rating plate.
The WR430-7.K.. instantaneous water heaters are supplied
with a gas pressure regulator that must be installed on the
heater before attaching the gas suppl line. See figure 6.
Failure to install the gas pressure regulator as shown in
figure 6 will be a violation of A.G.A. and C.G.A. certification
of the unit.
BOSCH water heaters are shipped from the factor with
the gas pressure regulators preset for the gas shown on the
rating plate to the correct pressure:
• in Canada, for high altitude operation;
• in U.S.A., for standard altitude operation unless
specificall marked as a high altitude unit.
GAS INLET PIPE
PRESSURE TAP T
APPLIANCE PRESSURE
REGULATOR
Figure 6 GAS MANIFO D PRESSURE TEST POINT
T For measuring correct regulator operating pressure.
Figure 7
RE IEF VA VE
The listed pressure relief valve supplied must be installed
near the hot water outlet at time of installation of the heater.
No valve is to be placed between the relief valve and the
heater. A drain line must be connected to the relief valve to
direct discharge to a safe location. Do not install reducing
coupling or an other restriction in the discharge line. The
discharge line must be installed so as to allow complete
drainage of both the valve and the line. See figure 5.
Figure 5

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OPERATING INSTRUCTIONS
WARNING!
If the water heater has been damaged or exposed to fire or
sooting, or if an part has been underwater, do not use. If
unit has been operated during construction or alterations
and exposed to above normal dust levels the heat exchanger
should be examined and cleaned regularl . Operation with
dust obstructed fins could be a health hazard. Immediatel
call a qualified service technician to inspect the appliance
and to replace an part of the control s stem and an gas
control which has been underwater and to clean the heat
exchanger assembl and water valve.
FI ING
Before proceeding with operation of the water heater make
sure that the s stem is filled with water:
• Make sure drain is closed. See figure 8, below.
• Open a nearb hot water faucet to permit the water to
fill the heater and piping.
• Close the hot water faucet after the water flows freel
and all air has escaped from the s stem.
The water heater is now read to be lit.
Figure 9
Figure 8
SERVICE HINT
The screen (strainer) in the water valve, located in the inlet
of the water valve, ma require occasional cleaning due to
foreign material in the water suppl . This will restrict the
flow of water and ma affect heater operation and prolong
filling time. To inspect the strainer, close the cold water suppl
valve ahead of the heater, disconnect the S-bend from the
inlet of the water valve and remove strainer from inlet. Clean
if required, replace strainer in inlet to the water valve,
reconnect S-bend and turn on water suppl .
Light the water heater in accordance with the instructions
on the Lighting and Operating Plate on the water heater.
For our convenience, the instructions are repeated here:
IGHTING AND OPERATING INSTRUCTIONS
1. STOP! Read the safet information above on this lable.
2. The gas valve must be shut off b putting the ON/OFF
switch to position “ ” Wait five (5) minutes to clear out
an gas. If ou smell gas, STOP! Follow “B” in the safet
information above. If ou do not smell gas, go to the
next step.
3. This water heater is equipped with a safet pilot burner
and an automatic ignition control s stem.
4. Set the ON/OFF switch (flip down cover plate on frontal
panel strip) marked / to the " " position. In this
position, the water heater is read to use. (See Fig. 9).
5. Turn the hot water faucet on the minimum flow rate
required to activate the heater. The automatic ignition
s stem first ignites the safet pilot burner which then
ignites the main burner in about 4 seconds.
6. The pilot flame will extiguish 10-30 seconds after the
burners come on. The burners will remain on until the
hot water tap is turned off.
7. Vent fan turns on and off with burner.
NOTE: On a first time initial installation, existence of air in
the gas suppl line and in the water line ma cause some
ignition dela . In that case, repeatedl open and close the
hot water tap in order to restart the ignition process until all
the air has been purged.
TO TURN OFF GAS TO APP IANCE
Turn off the manual lever on the gas suppl line to the heater
and set the ON/OFF switch to the OFF ( ) position.
To operate the heater, set the ON/OFF switch to position
“”. The switch is located behind the flip down cover
plate on the front panel strip.
To shut down the gas to the heater, set the ON/OFF
switch to position “ ”.
TOHEAT EXCHANGER
WATERVALVE
DRAIN PLUG
FROMHEAT
EXCHANGER

156 720 606 599
*Note: The high altitude ratings listed are Canadian Gas Association
high altitude ratings for the appliances and are onl valid in
Canada. In the U.S.A. the National Fuel Gas Code, ANSI 1-
1988, recommends for high altitude installations, above 2,000
feet, that the input rate be reduced 4% for each 1,000 feet
above sea level.
Your appliance dealer and/or our local gas supplier should
be consulted in regard to an high altitude installation. If
field adjustment is required it should be performed b a
qualified serviceman experienced in such work.
TEMPERATURE REGU ATION
The BOSCH WR430-7K is equipped with a modulating
gas valve which adjusts the flow of gas to the main burner
in proportion to the water flow rate. Within its heating
capacit the WR430-7K attempts to maintain the set
temperature rise across the heater. This temperature rise
can be set in range of 25°C - to - 50°C (45°F - to - 90°F),
b means of the water flow selector. See Figure 11. When
the water flow selector is turned to the right hand stop the
water heater is set for 50°C (90°F) temperature rise; when
the water flow selector is set to the left hand stop it is set
for 25°C (45°F) temperature rise.
PRESSURE REGU ATION
The pressure regulator supplied with the water heater is
adjusted to operate on the gas specified on the rating plate
and:
• in Canada, is factor preset to deliver gas at the high
altitude setting listed on the rating plate and as shown
below.
• in the U.S.A., is factor preset to deliver gas at the
standard altitude setting listed on the rating plate and as
shown below.
The pressure setting of the gas pressure regulator should
be checked at installation to assure that the setting is correct
for the gas being used and the altitude at which the
appliance is installed. See rating plate on the unit, Table 1,
below, for proper setting.
In Canada, for a heater being installed at standard altitude
(0-2,000 ft above sea level) the manifold pressure should
be reset at installation to the value shown on the rating
plate, or Table 1, below, for standard altitude.
Increases temperature
and decreases flow
Temperature Adjustment Knob
Decreases temperature
and increases flow
REGULATOR
SUPPLY TEST
PRESSURE TAP T
ADJUSTABLE
PRESSURE REGULATOR
Figure 11 - Principles of Operation
With the water flow selector turned to its right hand stop
position (50°C rise setting) and with an inlet water
temperature of 10°C (50°F) the outlet water temperature
will be maintained at approximatel 60°C (140°F) in the
water flow rate range of approximatel 2 litres/min. (0.5 U.S.
gals./min.) to 9.5 litres/min. (2.5 U.S. gals./min.).
The minimum flow rate for operation, the “Threshold Flow
Rate” referred to in the lighting instructions is 2 litres/min
(0.5 U.S. gals./min.). If the water flow rate is below this level
the main burner will not fire. If the flow rate exceeds 9.5
litres/min (2.5 U.S. gals./min.) the temperature rise aross
the heater will decrease in proportion to the rate above this
temperature.
HIGH TEMPERATURE IMIT SWITCH
The BOSCH series instantaneous gas water heaters are
equipped with a high temperature limit switch with a set
point of approximatel 90°C (195°F). If the water temperature
at the sensing points exceeds the set point the switch will
open, interrupting the safet circuit and stopping gas flow
to the pilot and main burner.
Outage as the result of high limit operation indicates that
the heater is not functioning properl . The heater should be
checked b a qualified serviceman and the reason for the
malfunction is corrected.
Figure 10
The gas pressures specified below refer to flow pressure
taken at the pressure tap in the gas inlet pipe just above the
pressure regulator, (see figure 10) while the heater is
operating at full input.
Gas pressures read at burner test point D (see fig. 7) page
13.
Table 1.
Appliance Regulator Pressure Setting
kPa Inches, W.C.
natural 1.41 5.38 standard
propane 2.61 9.9 (0-2,000 ft.)
natural 1.14 4.4 high*
propane 2.09 7.9 (2,000-4,500 ft.)
Altitude
WR430-7K
Model Type of Gas Pressure tap

16 6 720 606 599
Do not enlarge the orifice.
Do not use an wire or sharp object to clean orifices. Natural
gas orifices are large enough that ou can usuall clean
them b blowing through them. To access the pilot orifice,
remove 2 screws holding pilot assembl in place. Then loosen
compression fittings to expose pilot orifice.
Heat Exchanger should be visuall examined once a ear
or more often in dust areas. If fins at top show dust or
debris accumulation, remove and clean with brush and soap
water.
Fig. 12 - Characteristic Pilot Flame
To clean the pilot burner and/or the pilot orifice: Turn off
the gas to the unit. Set the On/Off switch to Off (position
). Remove the cover of the heater. To do so, pull off the
temperature adjustment knob and unscrew and remove the
plastic collar. Pull main cover out toward ou and lift up and
out. The pilot orifice should be cleaned or replaced.
Main Burner Flames: The main burner flames should be
blue, with a more intense blue cone in the center core. Yellow
flames could be a sign of plugged or dirt burners, or a
blockage on the heat exchangers fins. If some burners have
ellow flames while others have good flames, it is likel that
dust, lint or spider webs have partiall clogged the burner
venturis. To clean the burners, contact a gas service person.
Mineral Scale Build-up: In hard water areas the Bosch,
when operated at lower temperature settings, tend not to
accumulate mineral buildup. If however, the heater is used
at the higher temperature settings and the water has a high
mineral content, periodic descaling ma be necessar . The
heating coil should be removed and flushed with a descaling
solution. Signs of scaling are rising outlet temperature and
knocking noises when water is flowing.
Flue gas safety device:
The flue gas safet device must not under an circumstances
be switched off, simulated or replaced b an other
component.
Operation and safety precautions
The flue gas safet device checks the effectiveness of flue
gas extraction b the flue. If it is inadequate, the appliance
switches off automaticall so that the combustion fumes do
not escape into the room in which the appliance has been
installed. The flue gas safet device resets after a cooling-
down period.
If the appliance shuts down while in operation, ventilate the
room. Wait about 10 minutes then restart the appliance. If
the problem recurs, call an engineer. The user must never
make an modifications to the appliance.
Removal of the Heat Exchanger
1. Shut off the gas and water cold
suppl lines to the heater and remove
the front cover.
2. Remove the drain screw from the
bottom of the water regulator and
open the hot water tap to allow the
unit to drain.
3. Remove cover and unscrew metal
retaining bar at the top front of the
heat exchanger
4. Undo water connection nuts at
heat exchanger from both sides 5. Tilt the heating bod to the front
at the top and lift awa from the
heater.
Estimated service time is 10 minutes to re & re, plus cleaning time
MAINTENANCE AND SERVICE
Approximatel once a ear, the Bosch should be checked,
cleaned and serviced as necessar . To remove the front cover,
first remove the incandescent particle tra , then pull off the
temperature adjustment knob and unscrew and remove the
plastic collar. Pull main cover out toward ou and lift up and
out. THE FOLLOWING OPERATIONS SHOULD BE
PERFORMED BY A QUALIFIED SERVICE PERSON:
Vent System: Should be checked annuall . Clean and repair
as needed. See Preventative Maintenance Page 11.
Water Valve: The water valve on this heater should be
serviced periodicall . The frequenc will depend on the
mineral content of the water and conditions of use or
whenever signs of corrosion appear at the gas and water
valve joint. Check that the water inlet filter (#36 on Figure
18, page 20) is clean. Diaphragm should be replaced ever
7-8 rs. in residential applications and 3-5 rs for commercial
applications. In acid water areas the venturi should also be
replaced at the same time (#30 on Figure 17, page 21).
Pilot Flame: The pilot flame should burn with a clean, sharp,
blue flame and should resemble the diagram in Fig. 12. If
the flame is soft and ellow the pilot screen ma be dirt or
the pilot burner orifice ma need to be cleaned or replaced.
The pilot flame should be approximatel 2 inches long,
extending past the flame sensor. If the flame is too small, it
will not reach the flame sensor and the burners will not
come on.
3mm
Correct gap between
pilot burner tip and
electrode tip
Sparking plug
electrode
Flame sensor
Sparking
plug
electrode
Pilot cap orifice
Pilot tube

176 720 606 599
Pilot does not spark with
water flow
1 Close water tap
2 Remove screw cap and
unscrew adjusting screw til
sparking starts
3 Screw in turning one and
half turns more
4 Replace screw cap
Pilot is always sparking
without water flow
1 Close water tap
2 Screw in adjusting screw, till it
stops sparking
3 Continue to screw in turning
one and a half turns more
ADJUSTING
SCREW
TROUB E SHOOTING
Introduction
The Bosch WR430-7K burners are activated by a water
flow valve. Nu erous water related proble s can cause
this water valve to alfunction such as: Insufficient water
flow volu e to activate the burners at its ini u flow
require ent; Dirt in the water flow valve causing it to
alfunction; Sedi ent build-up in faucet aerators, or shower
heads; Uneven pressures between cold and hot, (with single
lever faucets) Plu bing cross overs. These water flow related
proble s can cause the heater to deliver less than its full
output, or to fail to ignite or to shut down co pletely.
Problems are stated in upper case, bold face. Most common
causes for the problems follow in order of likelihood. The
suggested solutions require that the cover be taken off. To
do this, remove incandescent particle tra , pull off the
temperature adjustment knob and unscrew and remove the
plastic collar. Pull main cover out toward ou and lift up and
out.
NO SPARK AT THE PI OT
1. ON/Off switch is not “On” (Position ).
The On/Off switch is located behind the flipdown cover
plate on the front panel strip. See fig. 9.
2. Water flow is not sufficient to activate heater.
Water flow rate at faucet is below minimum flow needed to
activate heater. When temperature adjustment knob is turned
all the wa clockwise, the Bosch WR430-7K requires 1/2
gallon per minute flow to activate the heater. As a reference,
this is a flow which would fill a quart jar in 30 seconds. If
the temperature adjustment knob is turned full
counterclockwise, a flow rate of 1.1 gallons/minute is required
to activate the heater.
3. Water inlet filter is clogged
Water flow is restricted, preventing needed flow to activate
heater. Clean water inlet filter screen.
4. Cross over in water lines
To confirm there is no cross-over in the plumbing, shut off
the cold water suppl to the Bosch water heater and open a
hot water faucet. There should not be an water flowing at
that faucet. Water running is a sign of a plumbing cross
over. Consult our plumber.
5. Microswitch needs to be adjusted or replaced.
If ou do not hear a click when a tap is opened, the
microswitch needs to be adjusted. See Fig 13 for adjustment.
Replace the microswitch if the adjustment does not solve
the problem.
Fig. 13 - Microswitch Adjustment
Maintenance*
If faults occur on the flue gas safet device, proceed as
follows:
-Undo flue gas safet device fixing screw.
-Unplug igniter unit connector.
Replace damaged component with new one and refit using
the reverse of the procedure set out the table above.
Function check*
Flue gas safet device function check:
-Disconnect flue pipe
-Replace with pipe (about 50 cm long) with sealed end
-Fit pipe verticall
-Start up appliance at rated output and set temperature
control to maximum temperature.
Under those conditions, the appliance should shut down
after two minutes. Remove temporar pipe and reconnect
flue pipe.
* This work ma onl be carried out b an approved engineer.

18 6 720 606 599
PI OT SPARKS CONTINUOUS Y WITH
NO WATER RUNNING
1. Microswitch needs adjustment
If no water is running, but pilot electrode continuousl sparks,
the microswitch screw to the water valve needs adjustment.
See Figure 13.
PI OT IGHTS BUT BURNERS
WI NOT COME ON
1. Confirm water valve assembly is working properly.
2. Confirm the flame sensor is in its proper position.
3. Confirm the burner electrovalve switch is functioning
properly. Contact our service person or call:
Canada 1-800-663-8405, U.S.A. 1.800-824-7337.
4. The electrical Control Box (Fig. 14) may need to be
replaced. Contact our service person or call:
Canada 1-800-663-8405, U.S.A. 1.800-824-7337.
MAIN BURNERS GO OUT DURING HOT
WATER USE
1. Flow rate diminished below activation rate: 0.5 USGM
(2.5 l) in hot position, 1.0 USGM (5 l) in warm position.
2. Unbalanced pressure in the water lines
The added restriction caused b the Bosch in the hot water
s stem can result in uneven pressures between the cold
and the hot. In such cases when mixing cold water at the
tap, the lower hot water pressure ma be overpowered b a
much higher cold water pressure, which ma cause the
Bosch burners to shut down. Make sure faucet aerators
and showerheads are free of minerals and dirt. Do not add
an flow restrictor to the shower head.
3. Check gas supply
4. ECO (overheat sensor) tripped due to overheating
5. Minimum inlet pressure on well is inadequate
Check the inlet water pressure. On a private well, raise the
minimum pressure setting to 40 psi for best performance.
Confirm that the pressure tank is not water logged.
Fig. 14 - Electrical wiring diagram
8 - ionization probe (flame sensor)
9 - fuse
10 - pilot electrode
11 - control box
12 - power cord
13 - exhaust fan
1 - microswitch
2 - circuit interrupter
3 - temperature limiter
4 - sensors of exhaust gases
5 - burner electrovalve
6 - pilot electrovalve
7 - gas control valve
7. Cold incoming water connection made to wrong side
of heater
Make sure cold water inlet connection is on the right side of
heater when ou are facing heater.
8. Water valve parts may be dirty of components damaged
First check that venturi is free of dirt particles. Water valve
and component parts must be totall free of dirt. In hard
water areas, mineral deposits can eventuall (3-5 ears in
hard water areas) corrode the water valve parts to a point
where the will need replacing. An sign of moisture at the
top of the water valve is a sign that the water valve needs to
be serviced immediatel .
9. oose connection at the ECO
Ignition sparker will not operate if the electrical circuit is
interrupted. Check that the connections to the ECO are
secure and tighten if necessar .
SPARKS APPEAR AT PI OT WHEN HOT WATER
TAP TURNED ON, BUT PI OT AND BURNERS
WI NOT IGNITE
1. Air in the Gas ine
Normall this is a problem at time of initial installation, after
the pipes have been worked on, or after a gas suppl line
has been allowed to empt . Bleed the air trapped in the gas
line b turning the hot water faucet on and off until the air
has been cleared from the line.
2. No gas to the Bosch
A. Gas cock on gas line ma not be open
B. Gas regulator ma be shut or damaged. Replace or unjam
the regulator. Note: The regulator furnished with the heater
is exclusivel designed for low gas pressure. Excessive
pressure will lock it up. Jamming usuall happens when using
propane gas if the gas pressure between the gas tank and
the water heater’s gas regulator has not been reduced. See
Page 15 for recommended correct gas pressure. To unjam a
regulator, consult our gas supplier.
3. Pilot orifice or gas valve is dirty
Clogging of the pilot burner can be caused b dust in the
air or dirt in the gas. The pilot orifice or gas filter ma need
to be cleaned or replace.
4. Water valve assembly needs to be checked
If the pilot orifice is clean, the water valve assembl should
be checked. The adjustment screw on the water valve micro-
switch ma not be tight enough (Fig. 13). Remove central
cap beneath micro-switch assembl , carefull loosen the
adjustment screw until the pilot light ignites. At that point
retighten the screw one and a half turns.
5. Pilot electrovalve switch may need to be replaced (See
Fig 14).
Call our service person or call: Canada 1-800-663-8405,
U.S.A. 1.800-824-7337.
6. Electronic Control Box may need to be replaced, (See
Fig 14).
Call our service person or call: Canada 1-800-663-8405,
U.S.A. 1.800-824-7337.

196 720 606 599
HOT WATER TEMPERATURE
F UCTUATES
1. Unbalanced pressure in waterlines.
The added restriction caused b the Bosch in the hot water
s stem can result in uneven pressures between the cold
and the hot. In such cases when mixing cold water at the
tap, the lower hot water pressure ma be overpowered b a
much higher cold water pressure, which ma cause the
Bosch burners to shut down. Make sure faucet aerators or
shower heads are free of minerals. Do not add any flow
restrictor to the shower head.
2. Cold water is mixing with the hot water between the
Bosch and the outlet.
See 4 under “NO SPARK AT THE PILOT”.
3. Inlet water pressure is erratic due to inadequate supply
water pressure or saturated pressure tank on well
system.
Check the inlet water pressure. On a private well, raise
minimum pressure setting to 40 psi. Confirm that the
pressure tank is not water logged.
4. Gas pressure is too low.
See page 15 for correct specifications.
WATER IS TOO HOT
1. Check for lime build-up. (See mineral scale p. 16)
2. Temperature Selection too high
Turn the temperature adjustment knob counter-clockwise
(to the left) to lower the maximum water temperature.
Note: This will increase the activation flow rate.
3. Inlet water temperature is too hot (as with preheated
water.)
4. Insufficient water pressure
WATER IS NOT HOT ENOUGH
1. Temperature selection too low.
Change the setting. Turn the temperature adjustment knob
clockwise (to the right).
Note: This will decrease the activation flow rate.
2. Water flow through the heater is higher than the
capacity of the Bosch to heat it.
This can be due to too high water inlet pressure (60 psi
max. for best results) or due to acid water erosion of venturi.
Check venturi (Part #39, Fig. 19 page 20).
3. Btu input is too low due to insufficient gas pressure.
It is extremely important for a tankless instantaneous water
heater to have the right size gas line to obtain the correct
gas pressure.
See specifications on page 15, table 1. Unlike storage tank
water heaters, the burners of a tankless water heater must
be ver powerful to heat water instantaneousl since the
do this onl at the time hot water is actuall being used. It is
therefore imperative that the gas pressure requirement be
met exactl . Insufficient gas pressure will directl affect the
water temperature at the time of usage. See page 15 for
correct gas pressure settings and fig. 11 for locations where
gas pressures are taken.
4. Btu input is too low due to insufficient gas supply.
Make sure our main gas line is full opened. If using LP
gas, be sure that the size of the propane tank is adequate to
suppl the required gas pressure.
5. Cold water is mixing with the hot water between the
Bosch and the outlet.
Compare water temperature at outlet of the Bosch (hold
the Bosch’s outlet pipe with our hand) and at the tap. If
these two are ver different, check for mixing valve or
plumbing crossover (see “NO SPARK AT THE PILOT”
paragraph #4). Where automatic “anti-scald” valves are
required b code, lower the temperature setting on the Bosch
as much as possible and balance the pressure between
cold and hot water after the Bosch.
6. Parts in water flow valve are corroded so that the
gas passage is not fully opening.
Contact our service person or call:
Canada 1-800-663-8405, U.S.A. 1-800-824-7337.
6. Check Blower Fan. Is it operating when burner comes
on?
7. Check flapper in outside vent termination for free
movement.

20 6 720 606 599
Fig. 15 - Diagram of WR430-7K
1. Heat exchanger
2. Pilot assembl
3. Burner manifold gas
pressure test nipple
4. Main gas burner
5. Pilot gas tubing
6. Gas valve
7. Electronic control box
5
11
1
4
9
10
12
2
6
8
7
13
3
See fig 7,
page 13
See table 1 on
page 15
8. Power cord
9. on/off switch
10. Temperature adjustment
selector
11. Microswitch
12. Gas inlet gas pressure test
nipple
13. Exhaust Fan