Problem with Glow-worm boiler

[mightyhugh]

My boiler, a Glow-worm space saver F, has stopped working. Its normal sequence of operation when starting up is that the flue extractor fan starts running, then a spark electrode lights a pilot light which then lights the main burner. However, now all that happens when you switch it on is a clunk and a faint whirring sound (I'm not sure if this is coming from the boiler itself or just water circulating from the water pump). There doesn't seem to be any air blowing out from the flue and there is no sparking at the pilot light. Does anyone here have any idea what might have gone wrong and how to fix it?

[Christian McArdle]

Well, you say the first element in the sequence is the fan starting. There will be various fail-safe mechanisms that abort the lighting sequence if the fan fails.

So perhaps the fan is not starting for a reason. Either it is broken, or the cable to it is, or the PCB is knackered.

There may be other failsafe devices, too. Perhaps the first step is really to start the water flow and only to proceed when flow is detected. I don't know enough about the boiler. Hopefully Ed Sirrett or raden will be along soon with the actual sequence or most likely failure mode for this boiler.

Christian.

[Fentoozler]

If the fan doesn't get up to speed, the air pressure switch won't click over and nothing else will work. you could try lubricating the fan assembly, else replace it. If the fan is getting up to speed, your air pressure switch may be faulty.

Angus

[Ed Sirett]

I've only met a couple of these boilers. However if the fan is not running then the acid test is to see if it's getting any power.

I have no reason to doubt raden's belief that these boilers have troublesome fans.

[John]

The clunk could te easily be the fan having failed bearings and instead of spinning the magnetic field drags the rotor sideways onto the stator. If you are competent open up the dasing and watch what happens. If the fan is at fault try Geoff at CET

[Cicero]

=============== The 'whirring' sound which you describe might be the fan working normally (despite the fact that there is apparently no air blowing out). The tubes from the fan to the air switch have a tendency to block up (only about 3mm ID). If this happens the light-up procedure fails. If you are confident enough open the boiler, disconnect the air tubes and check that they're clear of obstruction.

Cic.

[mightyhugh]

It turned out the fan was jammed. Thanks for your help everyone.

Hugh