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Andrew Smith
Andrew Smith, Engineer
Category: UK Plumbing
Satisfied Customers: 3633
Experience:  Domestic Gas, Commercial Gas, LPG, Unvented Hot Water, Part P Electrical, Commercial Catering
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Boiler keeps lighting every now and then of its own accord.

Customer Question

Boiler keeps lighting every now and then of its own accord. Programmer is off, thermostat is on lowest. Boiler serviced in September... Glowworm flexicom 12hx
Submitted: 1 year ago.
Category: UK Plumbing
Expert:  Andrew Smith replied 1 year ago.

This is a heat only boiler, so you have a cylinder. Do you not think it is keeping the hot water at the correct temperature?

Customer: replied 1 year ago.
we have a cylinder. The water is hot, no problems there. The boiler seems to have a mind of its own. No longer responds to the set programme.
Expert:  Andrew Smith replied 1 year ago.

It could be a problem with your motorised valve.

This part should be in the airing cupboard too, a silver or white box on the pipework. It turns on the pump and boiler when it is opened by the programmer, if it sticks then it can fire them up outside the set times.

Customer: replied 1 year ago.
Hi. Motorised valve was stuck in the notch above the 'manual' writing. I released it and it sprang slowly to the 'auto' writing on the casing. See how it goes... Just so I know, what end should the valve be on? Auto or manual?
Expert:  Andrew Smith replied 1 year ago.

Auto, also tight when on hot water and slack when on heating

Customer: replied 1 year ago.
Ok thanks for the replies. I have reset the progammer & the thermostat back to what they were both on before the problem started. Just have to wait and see what happens! ...
Expert:  Andrew Smith replied 1 year ago.

No problem - let me know

Customer: replied 1 year ago.
Seems to have sorted itself out now.... Although I think the motorised valve may have been fitted the wrong way round by the builders. House built in 2008.... We've always had a issue with needing heating on to have hot water. I don't know if it's a wiring fault, or just that the valve is on the wrong way round.
Expert:  Andrew Smith replied 1 year ago.

ok, try that and come back if you get stuck