Hi folks, any ideas on this one? My central heating water pressure on the combi boiler keps increasing until dripping from the safety vale at about 3 to 3.5 bar. I keep letting water out of the system, but after a day or so the pressure is high again. This ISN'T coming from a leak in the tap which fills the heating system - checked by disconnecting this althogether. So I suppose the only other place it CAN be coming from is the domestic hot water feed?

Any ideas gratefully recieved!

Cheers,

Rich, February 2008

we had the same problem with our boiler and it was a blocked pipe, so pressure was building up with no where to go

Sarah, January 2009

don't need the boiler out. it may only have a faulty valve etc.
only if it's buggered altogether it has to be changed.

hi-spec plumbing & heating, February 2008

... so am I!

That's the big bugger at the back riight? Boiler out job...

thanks (I think!!)

Rich, February 2008

Expansion vessel deflated.....

dpheating, February 2008

Hi there - yes, ift does drop most of the way back down when the heating is off - but VERY slowly (ie takes a full day). Have tried isolating boiler stopcock, pressure still increased with CH on - it was this that made me think it might be the DHW system at fault...

Rich, February 2008

does it drop back down when heating off
isolating the mains water to the boiler not the filling or just close the house stopcock.

hi-spec plumbing & heating, February 2008

This is with the heating ON. Running the DHW for a time has a small increase in system pressure.

Pressure still seems to increase with the CH on even if the feed to the DHW is turned fully off.

(Or did you mean the stopcock to the whole house?)

thanks, Rich

Rich, February 2008

is this with heating on or off it rises?
shut the main stopcock does it stop rising then ?

hi-spec plumbing & heating, February 2008