Another Combi Boiler problem

Rhino666

Everything seems to be going pear shaped for me at the moment and now my Vaillant VCW-GB 242 EH combi is playing up. I recently drained the system down to do some work on the radiators. All has been refilled, bleed valves bled according to the engineers commissioning instructions and the boiler is providing hot water and central heating.

The problem is that the boiler pump runs as normal when I turn on my hot water but does not stop when I turn it off, even when the central heating is not operating. Whilst the pump is running for no apparent reason the boiler will ocasionally fire up for a few seconds before going out. I am resorting to turning the boiler hot water switch off which strangely enough seems to be disabling the central heating :-( My boiler has a main switch and a separate hot water switch and as I remember the central heating should run with the hot water switched off but I could be wrong here ?

The other weird thing is that the central heating temperature guage suddenly seems to have stopped working but as this looks like a simple probe on a pipe, is probably a totally separate problem.

Anyone help please as I seem to have lost the number of a contact who services the boiler for me.

Thanks

Rob