Boiler pressure dropping

[harveyb]

Hi all,

Have just moved into a house and have am attempting to get the boiler running, however, the pressure keeps dropping once the program is ended.

Thinking there could be pressure leak somewhere plus am noticing drops of water coming from the overflow pipe.

Friend mentioned it could be the expansion vessel?? Anyone got any ideas?

Boiler is Vaillant Thermocompact with a megaflow cylinder. Also, worth mentioning that I have a couple of radiators off for plasterting.

Thanks in advance.

 

[kevindgas]

2 things a combi doesn't like, 1. a dripping PRV 2. radiators missing.

1. replace the prv.
2. blank off rad valves properly or refit the rads!

the boiler pressure should raise about 0.5 to 1 bar when hot against when its cold anymore than that then look at a deflated pressure vessel.