boiler pressure increasing

[drsabrown]

Hi, We're having a problem with our condensing combi-boiler (Vokera): when we turn the central heating on, the pressure guage on the boiler rises and continues to rise until its at limit (3) whereupon the boiler begins to leak. I drained water out of the radiator until the pressure was down to about 2.5 (with the systyem hot), but the level then continued to rise to 3 again, so we switched the system off. There is a flexi hose between the a cold water pipe (which continues into the boiler) and the heating loop pipe which exits the boiler. This flexi hose has a tap at both ends (?). When the central heating is on and I grip the flexi hose, it feels like water is moving through it. My thought is that one or both of the taps is damaged on the flexi hose, and the heating loop is being constantly filled. I don't understand, however, why this wouldn't happen regardless of whether the central heating/pump is switched on. Our mains pressure has increased slightly since last winter due to water company fixing of leaks etc. Should I disconnect the flexihose? Replace one/both of the taps? Any advine appreciated.

Regards,

Simon

[Andy]

Can't see how you can be sure water is movingthrough the filler loop just by touching it. Normally it would only be a slight leak anyway and inaudible.

More likely your expansion vessel is shot, meaning that when the CH warms up, the increased volue of the warm water in it has nothing to escape to and the pressure builds to 3 bar whereupon the escape valve opens and bleeds water out.

Solution is either a new expansion vessel or a new charge of air put in the old vessel ( it could have a leaky air valve - bicycle type ).

The filling loop can be disconnected you know , actually it should be anyway so doing that would eliminate the filling loop from your line of inquiry.

cassini

[Ed Sirett]

Try the SealedCH FAQ below. It's a failed expansion vessel by the sound of it.

[drsabrown]

Thanks very much for the help - I will check out the FAQ.

Cheers,

Sim> >