Ideal Classic boiler does not ignite

[noos999]

Hi all

I have an Ideal Classic conventional boiler, approx 13 years old. The CH system is the type having a header tank in the loft. Over the past few days, it was making a whistling noise and was taking a long time to fire up (10 to 20 minutes from when it was turned on at the controller). Today it does not fire up at all, and it makes a fairly quiet humming noise when the controller is asking for heat. Any ideas?

thanks

Julian

[geoff]

In message , " [e-mail]" writes

Is the fan turning ?

Is there a spark clicking away ?

You need to discover at what point in the sequence it's failing

call for heat if temp sensor considers it's cool and O/H stat is short circuit fan comes on this transfers the air pressure switch which tells the pcb to a) spark and b) open the pilot valve pcb senses the pilot is alight pcb opens the main valve

[Andy Hall]

Is that how they still work?

I had a Potterton wall mounted job in the 70s that worked like that. The spark generator became class F, but I was able to figure out what was happening. Other than that, it was quite a good boiler.

[geoff]

Stelrad 25B pcb - basic and functional

[Ed Sirett]

That would be fairly typical of a 'Middle-tech boiler' The Potterton Profile would be like that, the Netaheat (possibly the one you had) was not very different. About the only thing that's different with the modern boilers is that the ignition is no longer in two stages, because the gas rate is variable.

[geoff]

Yeah, at the end of the day, the start up sequence is fairly standard, other than that the rest is just refinements

[noos999]

Many thanks for the advice! -it turned out to be the fan in the end

Julian

[geoff]

I hope you didn't buy a new one