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Can anyone tell me why my central heating comes on by itself: the radiators get hot and stay hot for around 1-3 minutes then the system turns back off again. This can happen any time throughout the day and night, and you can hear the system kicking in.

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Have you checked the thermostat and verified the heat is turned off? – The Evil Greebo Jan 10 '13 at 13:42
Yes the heat is turned off from the thermostat all the time,but if we need heat we just turn the thermostat up ourselves, we never use the timer – Dee Griffiths Jan 10 '13 at 21:31

If your system also heats your domestic hot water, it may be coming on to maintain the hot water temperature. Depending on the setup, you may be getting some hot water circulation through the radiators when this happens. Is the radiator system steam, or hot water? If it's hot water, can you tell of one or more of the circulators come on when the boiler runs?

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Most heating systems are setup to automatically turn on and off based upon the setting of a thermostat. When heat is required (i.e. thermostat reading lower than setting) then the heat system will come on till the thermostat reads a new temperature higher than the setting.

If your system is operating outside this automated procedure then it is possible that the any one of the following has failed in some way:

  • Thermostat not reading correctly
  • Wiring from thermostat to heat system is damaged
  • Relay and control board on heat system has failed or gone intermittent.

You may need the aid of a qualified heating specialist to troubleshoot problems like this.

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Thank you I will have a heating specialist look at it – Dee Griffiths Jan 10 '13 at 21:29

If you have a programmable thermostat check every program every day. It is possible a group program was set. I would suspect a thermostat issue 1st. Including a deflective one. If the weather has been below freezing it is possible there is a sensor over ride on a pipe that is suppose to engage only when freezing is imminent.

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