Glow-worm Micron 70FF Domestic boiler

9 Dec 2010
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United Kingdom
I have a Glow-Worm Micron 70FF domestic boiler which trips out every 2-4 days. I have replaced the Electrode, Thermistor, Circuit Board(PCB), Safety Temperature Limiter, Fan and Air Pressure Switch, but the tripping continues. The only thing left to replace is the Gas Control Valve. Any ideas of the cause and a remedy?
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Whatever possessed you to throw all those parts at your boiler? Very unlikely to be gas valve.What do you mean by tripping out?This sounds like RGI work as component and other tests are required to pinpoint fault.
I changed the boiler parts because no heating engineers were available because of the adverse weather conditions. I consulted with two heating engineers by telephone who both gave me the same remedies.
By 'tripping out' means the boiler stopped firing up and went into 'Reset Required'. After 'resetting' the boiler starts again runs for 2-4 days before tripping again.
Although I am not a heating engineer, before retiring, I used to do property maintenance which included plumbing and electrics. During my life I have fitted 3 boilers so I am quite capable of changing boiler parts.
The reason I asked for advice on this site is because I thought that this problem might be an inherent fault in this type of boiler.
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I changed the parts one at a time after each consultation. The first fault was when the boiler tripped and would not reset. After changing the recommended parts the Air Control Switch was the problem. Both engineers said it could not be this and by using the manufacturers fault test it tested OK! I only changed it because it was the only thing (apart from the gas valve) that I had not changed. So even the registered heating engineers got it wrong!

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