Why does my heating never go off?

Another hint that the hot water microswitch is broken will be that, when the CH is on although in summer mode (hot water only), the hot water temperature control sets the radiator temperatures.

c
October 2008

Probably because your domestic hot water microswitch is broken and jammed in the 'demand'position. Cheap and simple to replace (about ten quid), cut the wires to the old one and wire in new one with a chocolate block connector or use the crimps supplied.

To test if it is faulty, see if the central heating stays on when in hot water only mode, or unplug from control box and check for proper operation with continuity checker.

Take a photo on your camera phone of the old switch to the spares desk; there are two incompatible switches on the 80sp, you need to be sure to get the correct one.

c
October 2008

I have disconnected the 4 wires from the clock,and the boiler still comes on.......

Sandy Giles
September 2008

Think the clock must be faulty and packed in at the ON position, I would get an engineer quick as it will run up a large bill left on all the time.

Boiler Man
September 2008