Thanks for the suggestion but I must ask if there is a possibility of the programmer being at fault. My reason for suspecting the programmer is the way the fault has developed - the green neon HW and HW+CH switch was in the HW+CH position when a buzz from the programmer was noticed and the CH...
The fault has now progressed - when the selector switch is set to select HW & CH the boiler doesn't fire at all (it was previously doing the HW). With the selector switch set to HW only, the boiler fires up OK and HW is supplied. Does this suggest that the problem is elsewhere other than the...
The pump is running free when turned using a screwdriver and it was running OK the other day, which would suggest that the pump is not the culprit. There is this constant buzz from the programmer when the CH is selected - the room stat appears to be functioning correctly - it would seem that...
I think the model you are refering to may be different to the one I have as there is no blue box stuck to the casing. I've followed the wires which go to a pcb, other than that I'm stuffed.
I've checked the pump (the one one the left) and it is free.
I suspect the relay has failed because of the buzz when the central heating is selected. Where is the relay located?
Also, the suggestion that there are 2 reset buttons could be worth investigating - where are they??
Central heating was working fine the other day but now all I get is a buzz from the programmer. I've tried manually turning the water pump screw but the impeller rotates freely. I've tried resetting the system several times but this has failed to sort the problem. Any ideas??????