Central heating

[Marymint]

The central heating system switches itself on and off several times a day and night. I have turned the switch for the radiators, on the combi boiler, down to minimum, and the programmer to 5 degrees, but it still happens. Any advice would be very much appreciated.

[Hymie]

What make & model is it � this information will help others advise you?

It could be a faulty frost thermostat, or a fault in the circuit sensing the state of the frost thermostat � resulting in the boiler thinking that the ambient temperature has fallen below a preset level (circa 4C) and switching on to protect the boiler from freezing.

[Postdog]

Well surely on the boiler you have a few options.

1) adjust the timer so it doesn't come on at any time.

2) have a switch so you can change between heating on/Timed/off.

3) have a switch for hot water/central heating/both.

[Marymint]

Yes, Hymie, your advice makes sense, because although I have switched everything off, and the boiler is only supposed to be supplying hot water the radiators still come on. This system overrides the timer if it senses frost is about. It's an Ideal boiler, and is 5 yers old.

[Marymint]

The boiler is an Ideal Isar HE24.

[Hymie]

This model is not supplied with a frost thermostat as standard� but the installation guide gives instruction on changes to the wiring in order to fit a frost thermostat to the system.

The added frost thermostat is connected in the primary/live circuit and therefore unless you know what you are doing � you should not mess with the boiler�s electrics.

If you know what you are doing, the instructions show the frost thermostat wired directly from the Live terminal of the electrical supply to the boiler. Therefore if you can access this electrical connection point � you should see a second wire connected to the Live terminal, which leads to the frost thermostat. If you disconnect this wire (and make it safe), if the fault is with the frost thermostat, the boiler will no longer automatically switch on.

[Marymint]

Hymie, thank you for your full and very informative information. I have, to-day, had an engineer look at the boiler. Unfortunately he cannot remedy the fault without the instructions which I do not possess. I just assumed all qualified corgi engineers would be able to fix all problems with all boilers (especially as it was only been installed 5 years ago). I will now endeavour to chase these up. Again many thanks.

[Hymie]

I have a copy of the manual for this boiler (in pdf) and could send you it electronically.
But I don�t think it a good idea to reveal e-mail/other contact details on an open site such as AB.
But if your engineer can get hold of the manual � then there is no problem.
Otherwise perhaps others could advise if it is possible to message another Aber, without the message being accessible to all.

[Marymint]

I have been in touch with the Ideal boiler people, and, with a bit of luck, I will have the appropriate manual shortly - fingers crossed. Many thanks for all your help.