I have a problem with intermittent firing on a Ultimate 50FF boiler.
The boiler starts up ok as normal, comes up to temperature ok and starts to heat up the radiators / HW, with the burner cutting off / on as normal. After about 20 mins or so the main burner cuts out and immediately re ignites and this on/off scenario will continue every 20 seconds or so.
About two months ago, following exactly this scenario, the boiler cut out completely and although the igniter lit the pilot, there was no main gas on the burner. I found that one of the two gas valve solenoids was open circuit and replaced it. Hey presto, everything was fine, until recently when the intermittent firing phantom has returned.
I have put a voltmeter across the main gas solenoid (ie the one that I replaced in August).. When the boiler is operating normally there is 240v across the solenoid, each time it fires intermittently the 240v reduces to virtually zero, but immediately picks up back to 240 and the boiler main gas reignites. So Iguess its not the gas valve SOV, there must be some other reason why there is an intermittent loss of voltage to the SOV.
Can anyone help please, Weather is starting to turn cold up here.
Many thanks. Geoff.B
The boiler starts up ok as normal, comes up to temperature ok and starts to heat up the radiators / HW, with the burner cutting off / on as normal. After about 20 mins or so the main burner cuts out and immediately re ignites and this on/off scenario will continue every 20 seconds or so.
About two months ago, following exactly this scenario, the boiler cut out completely and although the igniter lit the pilot, there was no main gas on the burner. I found that one of the two gas valve solenoids was open circuit and replaced it. Hey presto, everything was fine, until recently when the intermittent firing phantom has returned.
I have put a voltmeter across the main gas solenoid (ie the one that I replaced in August).. When the boiler is operating normally there is 240v across the solenoid, each time it fires intermittently the 240v reduces to virtually zero, but immediately picks up back to 240 and the boiler main gas reignites. So Iguess its not the gas valve SOV, there must be some other reason why there is an intermittent loss of voltage to the SOV.
Can anyone help please, Weather is starting to turn cold up here.
Many thanks. Geoff.B