Glow Worm Micron 40FF fault

25 Jan 2009
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United Kingdom

Last night my Glow Worm Micron 40FF boiler stopped working. The LEDs indicate a fan or APS fault (fast flashing reset, slow flashing burner LED).

(The boiler was installed in early 2004.)

The pipe from the fan to the APS is clean with no blockages. The motor has power - it is magnetising (attracts a screwdriver) and is hums quietly but the fan is not turning. There are no signs of anything burning out - no blackening or smell. I tried gently tapping it an spinning it manually and it spins freely I've also applied WD40.

It sounds to me as though the fan motor has failed. Is there anything else I can try? Also is this a DIY job or not, I can't figure out how the fan body attaches to the boiler.

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you have already committed the offence of "illegal gas work" by removing the combustion cover from the boiler.

can you test for 240v at the fan connections?
if present then you would be right in suspecting the fan.
if not then it could be pcb or other component eg flow switch, pump.

its up to you if you want to carry on and do the job yourself but if you cannot figure out how to remove the fan
it maybe better to get an rgi in to put it all back together for you "safely" as they will do all relevant safety check.
Sounds like the fan, get an RGI in. The connection on to the flue outlet is a bit fiddly and a bit of a b1tch. Get it wrong and your boilers going to draw in products of combustion causing flame lift and another fault that's gonna have you stumped, intermittent lockout!
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Thanks for your replies.

I'm sure there is power to the fan as it is magnetizing and getting hot so I don't think I'll need to check the power. I think you've confirmed what I suspected.

I had no idea that removing the outer case constituted 'gas work' (illegal or otherwise), the manual does not make it clear what part is for the user and what is for the service engineer - I have no intention of going any further, I'll get the pros in.

Thanks again.

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