Please help: vaillant vcw282gb eh was working fine last season. I left it off as I do not use hot water. When started this season no hot water or heating. pressure was low I topped it up to 1.5 as per manuals but no luck. I checked servo valve the pin and diapharm is ok. Divertor is making the switches. when I switch it on I can hear the ignition ticking and then reset switch pops out. Don't know what to do.

Mike, November 2011

Thank you very much. I will try your instructions. Is it easy to get replacement tubes for this boiler.

Mike, December 2011

Most likely cause would be the pump sticking, if as you state the microswitches on the diverter valve are making, the pump can be ruled out. Other things to test:

20vdc to the solenoid, test between the solenoid and N9 on the motherboard (and an audible click when it is being activated), the voltage runs through the CH overheat stat, so if you haven't got 20v, check the stat is closed circuit.

PD Valve, on the front of the gas valve, there is a pressure differential valve (three screws removes it although it remains served by two copper tubes), start the boiler and feel the push rod, if it doesn't move, the PD valve and or tubes are blocked, when pushing forward (normal operation), this allows gas through the valve to the solenoid.

Carefree, November 2011