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

wrote in message
oups.com...
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


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

On Thu, 05 Oct 2006 02:30:53 -0700, drsabrown wrote:

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.

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

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards

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

Cheers,

Simon

Ed Sirett wrote:

On Thu, 05 Oct 2006 02:30:53 -0700, drsabrown wrote:

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.

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

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards