Boiler cutting out

My ideal elan 2 boiler ignites from cold with no problem. However after a period of time anything from an hour to longer it refuses to fire up. After a period of time when it obviously cools down it will then fire up again.
I initially thought there was a problem with the over heat stat, although this does not need to be reset as it does not pop up. However I replaced it with some success I thought as this morning the boiler fired constantly. However the same problem has started tonight again. I can hear the air pressure switch clicking in and the fan is running but still no ignition. Was wondering if it could be a pump problem, maybe the water can not get away from the boiler quick enough and its overheating and then is cutting out until its cooled down. However why doesn`t the overheat stat click in ?
Have phoned a round some heating engineers so far none want to know this side of Xmas. Would a new pump solve the problem or is my conclusion wrong? Don`t fancy being without consistent heat until after Xmas.
Any help appreciated
Andrew
An
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In an earlier contribution to this discussion,

Very unlikely to be the pump - if that fails, the overheat stat *will* trip and the boiler will then do nothing at all.
Does your boiler have a row of (maybe 3) LEDs which come on in sequence during the firing cycle? If so, how many of these are lit?
The boiler is clearly *trying* to fire - otherwise the fan wouldn't run. Depending on how far it's getting through the firing cycle you could have a problem with the pressure switch, pilot solenoid, ignition system or main gas valve. It's also possible - perhaps even likely in view of the fact that it seems to be temperature dependent - that you could have some iffy electronic components on the control board.
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Cheers,
Set Square
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Set Square wrote:

Agree with you here if the pump failed completely but the pump is at a guess 13 years old its pumping but I wonder if its not pumping as efficiently as it once was and the flow rate through the boiler has been dreuced therefore raising the temperatire within the boiler.

up.
Have put in a new pressure switch and I can hear that switching. The PCB is new as well so doubt that is at fault.
Still baffled.
Andrew
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I had a similar problem and it was down to the fan ,it did this for a while then eventually failed completely,I sourced a second hand one from http://www.cetltd.com really helpfull and saved a load of money to,had it over a year now and no problems.The owner often contributes on here but have not noticed him lately.
Alex
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I'm always here
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geoff

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geoff

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No it's a stelrad 7b pcb
no disco lights

Although it looks like a pcb fault to me, I can't see what would be susceptible to such temperature problems
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geoff

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