My combi boiler has been constantly on high pressue for a few weeks now, and is dribbling water out of the overflow pipe outside. If I bleed the radiator, the pressure builds up again within a matter of hours.

What is the reason for this and how much should it reasonably cost to get it fixed?
Thanks in advance!

Conrad, February 2010

If the boiler is3 or4 yrs old the expansion vessel hose is either blocked, or vessel needs replaced.

Greig bell, February 2010

Hi thanks for the response. Ive read somewhere else that it could be a pinhole in heat exchanger or something, does this sound plausible? Its happened to me before, and i had it fixed, it cost over £200.

Water pressure is constantly on red.

Conrad, February 2010

hi, it sounds like the filling loop is not closed fully or its faulty. it wont cost much to have it replaced.

khany, February 2010