Solenoid valve not staying open - gas valve or PCB replacement?

[gwynant]

My boiler - a 15 year old Ideal FF350 - has been starting to play up:

When it starts up the pilot light will ignite with a loud click, then take a long time to start the main burners, before switching off after 90 seconds or so. After another 90 seconds the sequence will start again and again until the timer switches it off (the boiler will go on and off like this for maybe 10+ times in 20 minutes).

Is it likely that the solenoid valve is playing up, or a problem with the circuit board? If the valve, for the Ideal boilers, I'm not sure if it requires the "gas valve" or the "gas valve kit classic" (see number 17 on this plumbase page for the boiler). I've been told that if it turns out not to be the valve the PCB will then need to be fixed instead.

I'm just trying to get an ideal of cost more than anything, especially as this is one of many elusive plumbing problems I seem to have at the moment!

Thanks in advance

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[cross thread]

get a gas engineer in as it sounds like a different reason and a service should sort it

 

[ollski]

You could do a resistance check on the gv solenoid without risking anything safety wise.

 

[gwynant]

Thanks for your replies.

You could do a resistance check on the gv solenoid without risking anything safety wise.

In that case, the engineer may not be 100% correct in saying that only after fitting a new gas valve (and then not being able to return it) would he be able to deduct whether it was that or the PCB?

 

[ollski]

to be honest a simple volt pen would go a long way to showing if the power was cutting out from the board but if you were to test live and neutral at the board when it drops out fluctuation would indicate a pcb fault and a steady voltage would probably indicate the gas valve....then you could measure resistance of the solenoids. All diagnosis is pretty simple when you can recreate the fault.

 

[durhamplumber]

to be honest a simple volt pen would go a long way to showing if the power was cutting out from the board but if you were to test live and neutral at the board when it drops out fluctuation would indicate a pcb fault and a steady voltage would probably indicate the gas valve....then you could measure resistance of the solenoids. All diagnosis is pretty simple when you can recreate the fault.

Why would you want to recreate the Fault and not find it?....any Fault finding is easy when you find the Fault!
Any job is easy when you know how,not that easy when you have no idea of volts,amp,dc,farads,millibars,or what component does what,when.