Bosch AquaStar 125FX LP Installation And Operating Instructions Manual page 16

The AquaStar 125FX pilot and burners are ignited 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.
16
Pilot does not spark with
water flow
1 Close water tap
2 Remove screw cap and
unscrew till sparking starts
3 Screw in turning one and a
half turns
Pilot always sparks
without water flow
1 Close water tap
2 Screw in adjusting screw
until it stops sparking
3 Continue to screw
turning one and a half
turns more
6 720 606 601
in