OK - I managed to fix mine..... it was due to a dry joint on the modulator board that had then burnt out. I fixed the joint again (and fixed quite a few others that looked about to burn out). Check the board for burnt out joints.
I dare say if yu get an engineer out - they'll just replace the whole board. Of course, yours might not be just a dry joint, but something else.
Hope this helps.
Rich
Rich B, January 2005
Neil - did you need to replace the main modulator board or the pcb which houses the two temperature sensors? Mines done exactly the same, i'm just trying to determine which board to replace.
Ta,
Rich
Rich B, January 2005
i have the same problem ,it may be as simple as your,sensor switch or (hope fully not) in my case a circuit board,the reason the water is still working is there are two sensors fitted in potterton puma ,good luck