I have an unvented system using a potterton boiler. Just before x-mas I noticed that the bathroom rad was permanently on. We do have a frost stat in the system but I assume this should not operate continuously. There appears to be no way to adjust the rad, if I turn it too far down the boiler trips out. There are 2 motorised valves in the system one marked with A-B and sliding s/w between them (not for manual op) and a s/w on the side. The other has a s/w at one end of which it says flushing only the other end I cant read. I have just noticed that the CH is coming on at times when it is supposed to be off, and at this moment it is heating the house even thought the thermostat is set to its lowest position.
Any Ideas most welcome
Any Ideas most welcome