Potterton Suprima CH boiler & connection to room thermastat

[GirlRacerRed]

Hi guys

I have often suspected that my room thermastat located in my lounge does not talk to the central heating boiler correctly. Yesterday I had the heating switched on and turned the thermastat to 15C. However the boiler carried on being fired up and eventually the room heated to 20C (I have a 3 month old baby so there's a separate thermometer in the room) but the boiler never switched itself off once it had reached the required temperature. I had originally thought that the room thermastat was broken so have replaced this, but still the boiler does not switch off when it reaches the set temperature.

Can anybody give me any tips on how to check whether the room thermastat is talking to the programmable timer and the boiler?

Thanks in advance

 

[johnboy6083]

is the thremostat actually connected at the boiler? When i moved into my house, we didnt have a stat, and the connections were linked, so the boiler worked.

 

[GirlRacerRed]

that's a good question johnboy. there's definitely electricity getting to the thermastat because it clicks when I turn the dial to see what the temperature is at. however, I wouldn't be surprised if the stat wasn't connected at all to the boiler. this whole house has been a disaster since we moved in. our gas engineer advised that our boiler wasn't properly wired to the programmable timer when we first moved in.

anybody know how I will be able to test whether the stat is connected to the boiler? I don't have the instruction booklet to the boiler as the house was a repo when we bought it and the previous owner was somewhat lax with home maintenance.

 

[topquark]

Here's the guide for the HE: http://www.potterton.co.uk/docs/101209_Potterton_Suprima_HE_Range_installer_guide.pdf

That'll prob give you enough clues as to how it should be wired.

 

[johnboy6083]

a thermostat doesnt need electricity to click as you put it. It is a glorified switch. that is it. You could test that you have power to the common terminal on the stat, and also that you connected it properly, ie normally open. when you turn the stat to its highest setting, you should get continuity across the stat, and when its at its lowest setting, you should have open circuit.