My boiler has stopped lighting - it goes thhrough the normal sequence, fan on, click of pressure valve, clunk of gas solenoid, ticking of spark, but nothing happens.
I took the front off, and there is no gas coming out of the pilot light nozzle while the spark is ticking. Is it possible for the gas valve solenoid to go clunk but no gas to come out? Is the gas valve faulty, or could something else cause it?
TIA
Bob
Sounds like blocked pilot jet but make and model of boiler would be helpful.
Sorry, it is a Ravenheat RSF 82E. The pilot jet, holey outer holder thingy and pipe are clear - the pilot jet nozzle is a small brass hollow bullet thingy with 2 pin holes in it.
Bob
Go here Bob.
In message , Bob Smith writes
Has someone dropped a bag on the main stop c*ck lever ?
I've made that successful diagnosis twice this year and it happened to a neighbour last year, so it's not that uncommon
(Do you have any other gas appliances - are they working or not )
OR
are you sure that it's the GV solenoid and not the relay on the pcb ?
(test the resistance of the solenoid and whether you have volts to the solenoid, - or the plunger could be stuck, 'it it wirra 'ammer)
OR
you might have some crud which has dropped into it
take a look
In message , Heliotrope Smith writes
This is one case where I don't think the make and model are at all relevant
----- Original Message ----- From: "geoff" Newsgroups: uk.d-i-y Sent: Thursday, October 11, 2007 10:33 PM Subject: Re: Boiler not lighting
Gas cooker working fine, full blast roaring flames...
Will have to borrow a volt counter from work, but I am pretty sure the gas valve is going - it is a big CLUNK - when I take the blue relay box off, I get the little relay click and no CLUNK.
Got into it how? Through the gas pipe? Can you get into the valve itself without having to replace seals etc?
I took the solenoids off, and could see 2 cylinders that go inside the solenoid coils. These were clean, and I assume the moving parts are inside (although there are springs on the outside).
The flowchart leads me to the gas valve (assuming I have 230V on the gas valve - the CLUNK gives me confidence it has). I used the flow chart before when I was having wierd intermittent not lighting problems, and it did not help (different part of light up cycle this time). When I replaced the ignition board (in the blue box) that fixed it. The "replace ignition board" boxes on the flowchart could not be reached by answering the questions correctly!
So could the gas valve be clunking but a vital part inside not be moving?
Bob
I think he was asking so he could point me at the flowchart (I already have the manual printed out, spiral bound and living in the airing cupboard)
Bob
In message , Heliotrope Smith writes
Really, you don't need a fault finding chart for this, while a manual might be useful to him, teh solution should be easy to find, you're just clouding the issue
In message , Bob Smith writes
have you not used it for a while? The slug might be moving but the rubber seal sticking
I was serious about whacking it
dropped off the heat exchanger
no
First check that the pilot solenoid isn't open circuit, then check that you have volts to it and both are true, and you've thumped it around a bit and you are sure that you have a gas supply, you need a new gas valve
Can it be opened at all? Would I need a seal kit, or is it too dangerous to reuse?
OK, will get volt counter today from work.
I have already tapped it a few times in different directions. Should I hit it really hard? Is there an optimum direction (I was thinking of along the axis of travel), or should I give it a beating from all directions?
Bob
In message , Bob Smith writes
They are just not meant to be disassembled, and unless you are VERY confident in your abilities, it's just not a road to go down. Since you are having to ask, I would suggest that it's not something you should try - what if it leaks and you cause an explosion ?
basically what can happen if a valve hasn't been used for a while is that the rubber seal can stick to the housing - this is what you are trying to see if you can dislodge
An extract from the (as yet unpublished) Boiler Repair FAQ on the subject of gas valves.
This is a genuine ?no user serviceable parts inside? piece of kit . Now let's be clear about this. There are no user serviceable parts inside. There are no professionally serviceable parts inside. There are no diy serviceable parts inside. In fact there are no serviceable parts inside even on Christmas eve. They cost less than £100, they do not need replacing very often if ever in the life of the boiler.
Are there any bits in which would be worth saving in one's useful bits box?
Owain
It has been in use over the summer for hot water, and for the last month for CH. When it stopped working, the rads were warm, and it was noticed that the hot tap was not getting hot (so it died on active duty).
Can the metal chunk that is moved by the solenoid break off whatever it is connected to and therefore still move and leave the valve shut?
Bob
Yeah, I'd go along with that
Why are they not serviceable? Serious question. I've encountered very few things which really, truly were unrepairable, and those were almost all electronic. What makes a relatively simple device like an electromechanical gas valve unrepairable?
Ian
Whilst I'm with you in spirit I plead a special case for this component.
1) There are likely to be rubber diaphragms and seals which even when new were vulnerable to damage. Some are more on the lines of a condom than a car tyre. These parts are now even more suspect to failing as the valve has failed (else why would you be opening it up).2) You need a way of verifying that the valve is working 100% after reassembly, a valve which lets by could have a lot of nasty consequences, one which I saw like that could have lead to a CO poisoning incident.
3) You may well find the culprit is a damaged/worn rubber component. Whilst O-rings, washers and springs are generic components diaphragms aren't. There is no source of supply for these sub-unit spares.
Ian
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