Bosch WR430-7K Serie Mode D'emploi page 17

Maintenance*
If faults occur on the flue gas safety device, proceed as
follows:
- Undo flue gas safety 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 safety device function check:
- Disconnect flue pipe
- Replace with pipe (about 50 cm long) with sealed end
Fit pipe vertically
-
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 temporary pipe and reconnect
flue pipe.
* This work may only be carried out by an approved engineer.
TROUBLE SHOOTING
Introduction
The Bosch WR430-7K burners are activated by a water
flow valve. Numerous water related problems can cause
this water valve to malfunction such as: Insufficient water
flow volume to activate the burners at its minimum flow
requirement; Dirt in the water flow valve causing it to
malfunction; Sediment build-up in faucet aerators, or shower
heads; Uneven pressures between cold and hot, (with single
lever faucets) Plumbing cross overs. These water flow related
problems can cause the heater to deliver less than its full
output, or to fail to ignite or to shut down completely.
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 tray, pull off the
temperature adjustment knob and unscrew and remove the
plastic collar. Pull main cover out toward you and lift up and
out.
NO SPARK AT THE PILOT
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 way 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 fully
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.
6 720 606 599
4. Cross over in water lines
To confirm there is no cross-over in the plumbing, shut off
the cold water supply to the Bosch water heater and open a
hot water faucet. There should not be any water flowing at
that faucet. Water running is a sign of a plumbing cross
over. Consult your plumber.
5. Microswitch needs to be adjusted or replaced.
If you 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.
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
).
Fig. 13 - Microswitch Adjustment
ADJUSTING
SCREW
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
17