Bosch WR430-7K - Manuel (Page 18)

18 6 720 606 599
PILOT SPARKS CONTINUOUSLY WITH
NO WATER RUNNING
1. Microswitch needs adjustment
If no water is running, but pilot electrode continuously sparks,
the microswitch screw to the water valve needs adjustment.
See Figure 13.
PILOT LIGHTS BUT BURNERS
WILL 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 your 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 your 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 by the Bosch in the hot water
system 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 may be overpowered by a
much higher cold water pressure, which may cause the
Bosch burners to shut down. Make sure faucet aerators
and showerheads are free of minerals and dirt. Do not add
any 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 you 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 totally free of dirt. In hard
water areas, mineral deposits can eventually (3-5 years in
hard water areas) corrode the water valve parts to a point
where they will need replacing. Any sign of moisture at the
top of the water valve is a sign that the water valve needs to
be serviced immediately.
9. Loose 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 necessary.
SPARKS APPEAR AT PILOT WHEN HOT WATER
TAP TURNED ON, BUT PILOT AND BURNERS
WILL NOT IGNITE
1. Air in the Gas Line
Normally this is a problem at time of initial installation, after
the pipes have been worked on, or after a gas supply line
has been allowed to empty. Bleed the air trapped in the gas
line by 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 may not be open
B. Gas regulator may be shut or damaged. Replace or unjam
the regulator. Note: The regulator furnished with the heater
is exclusively designed for low gas pressure. Excessive
pressure will lock it up. Jamming usually 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 your gas supplier.
3. Pilot orifice or gas valve is dirty
Clogging of the pilot burner can be caused by dust in the
air or dirt in the gas. The pilot orifice or gas filter may need
to be cleaned or replace.
4. Water valve assembly needs to be checked
If the pilot orifice is clean, the water valve assembly should
be checked. The adjustment screw on the water valve micro-
switch may not be tight enough (Fig. 13). Remove central
cap beneath micro-switch assembly, carefully 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 your 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 your service person or call: Canada 1-800-663-8405,
U.S.A. 1.800-824-7337.