Whats involved in fixing Vaillant Turbo Max Plus 837E?

This is probably the one and onl fault you can carry out without it being illegal. Top rear of the boiler about 6inches down the back is a schreader valve ( same as on any other inner tube etc). undo this. open the pressure relief just underneath the boiler (white or grey and will say 3 bar possibly) leave in the open position, this is the half open half closed position. water will go out through the PRV termination, once the pressure is down to 0. use a footpump and inflate to one bar. observe a stable pressure (may require to pump for few minutes to get rid of water around the bladder. once you have 1bar - shut the prv and remove te footpump. repressurise water to 1 bar and that should be that. Ideally it would be useful to renew the PRV as it may pass slightly as grit etc will stop it sealing.

paul
May 2010

could be the promlem, but what is causing it to drip, check the expanshion vessal for pressure should be about 1 bar if not use a bike pump to repreassrise to 1bar

erj
May 2010