1 hour ago Jo asked ... How to engage clutch on old sewing machine to engage needle?    |    Jacky asked ... Miele Vacuum cleaner?    |    Ben asked ... Toyota Yaris French or Japanese?    |    Andy asked ... How can I mend my MacAlistair 450w hedge trimmer?    |    Felix asked ... Hitachi vt-m70em?    |    Click here to ask your question

my vaillant boiler is saying a code com on it ?

what do I do when your boiler says com on it an no heating or hot water
mel, December 2016
It refers to a communication fault between the two circuit boards, I believe the display actually reads CON? It could be a fatal board fault or a poor connection between the two, with the power off, try separating and reconnecting the boards

Carefree, December 2016
You do a Google search for - say "Valliant 'Model' Com Fault" but you replace 'Model' with the exact model number of your boiler.

XXX, December 2016
link Click here to see other fixes for Vaillant.