Combi turns on for no reason All aspects of plumbing questions and answers, help, tips and information

[deguerre]

Hi, I have a combination boiler, sometimes it will turn its self on for a short time for no apparent reason, (its not a pre heating boiler BTW), no taps running, CH not on. It normally happens at night. Any ideas why it would do this?

[htg engineer]

Firstlt check you're not missing something simple like programmer set to timed mode ?

Could be a faulty sensor bringing the boiler on as the majority now have a frost stat. If the temperature drops the boiler will bring the heating on to prevent the pipes etc from freezing.

htg

[deguerre]

Hi thanks for the reply, the timer seems to be set correctly, I don't think it has been cold enough recently for the frost sensor to have come on, what type of sensor could be causing it?

I have a friend who is a gas engineer, but he doesn't have a clue what would cause it, maybe you could point him in the right direction?


Thanks.

[htg engineer]

Make and model of boiler ?

Sorry didn't explain properly. I'm not saying it has been cold enough - i'm saying the sensor/frost stat may be faulty.


htg

[chris_on_tour2002]

you need a boiler engineer. there is clearly a fault with a sensor somewhere. could be one of a number of things that have already been stated, but without actually looking at it, it's impossible to say.

[deguerre]

Hi sorry for not replying I've been busy lately, my british gas friend checked the frost sensor and said he thinks thats the problem, he has swapped it for a new one now so I will have to wait and see if the problem goes away.

Thanks for all your help.