Here's a strange one. Vaillant VCW 242 EH. Heating cuts out after a couple of seconds but keeps trying to hold the main gas jets on without success. Pump working, can't find a blockage. Changed the diverter valve. Still no heating

Chris, January 2011

I had yesterday the similar problem. Pump for hot water worked continuously even if there was no need for HW, and as a consequence, heating didn't worked. Called a local service (I haven't been there but my wife told me that he was just pushed something inside), so now I can only guess that microswitch of HW stucked somehow.

Mario, February 2011