Combi Boiler loosing pressure. PRV?
 

Got an C&M Britony boiler that has been loosing pressure for a while.

It appears that the pressure release valve drips to the overflow releasing
the pressure over time, or suddently gives way (say at 2 bar) and drops the
pressure. So far I have lived with this, and just topped up as required.

However! yesterday a leak started within the boiler, after examination the
leak has been progressive (i.e substantial limescale etc) and therefore been
leaking over time from the "air seperator". The leak is to the extent that
any water in the system is lost.

Obviously the air seperator needs replacing (cost about £25.00), would it it
wise to replace the pressure release valve at the same time?

"Sam" wrote in message
...
Got an C&M Britony boiler that has been loosing pressure for a while.

It appears that the pressure release valve drips to the overflow releasing
the pressure over time, or suddently gives way (say at 2 bar) and drops
the
pressure. So far I have lived with this, and just topped up as required.

However! yesterday a leak started within the boiler, after examination the
leak has been progressive (i.e substantial limescale etc) and therefore
been
leaking over time from the "air seperator". The leak is to the extent that
any water in the system is lost.

Obviously the air seperator needs replacing (cost about £25.00), would it
it
wise to replace the pressure release valve at the same time?



I've had two boilers, and the pressure release valve was set to 2.4bar on
one,
and 3bar on the other. It might actually say on the valve if you have a
look.
2 bar seems a little low to me for an overpressure valve, on the other hand
2 bar
seems a slightly high pressure to run a CH system at. Can you test the
overpressure
valve by filling the CH loop until the overpressure valve blows off: I
presume you have a
pressure guage on your combi. Also, what is the pressure of your boiler when
cold,
and what does it climb to when it fires up the CH? There are other faults
that could
cause your overpressure release valve to appear to be acting up. It should
not drip water
out of the overflow if the pressure is below its calibrated operating point
though.

Andy.

On Tue, 14 Jun 2005 12:36:31 +0000, Sam wrote:

Got an C&M Britony boiler that has been loosing pressure for a while.

It appears that the pressure release valve drips to the overflow releasing
the pressure over time, or suddently gives way (say at 2 bar) and drops the
pressure. So far I have lived with this, and just topped up as required.

However! yesterday a leak started within the boiler, after examination the
leak has been progressive (i.e substantial limescale etc) and therefore been
leaking over time from the "air seperator". The leak is to the extent that
any water in the system is lost.

Obviously the air seperator needs replacing (cost about £25.00), would it it
wise to replace the pressure release valve at the same time?

The SealedCH Faq may help you.


--
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

Can you test the overpressure valve by filling the CH loop until the
overpressure valve blows off: I
presume you have a pressure guage on your combi. Also, what is the
pressure of your boiler when
cold, and what does it climb to when it fires up the CH?

Operates at about 3bar, but "drips" virtually continously till pressure get
down to 0.

When refilled, usually take it to 1 bar, when operating (hot) may reach
1.5-2bar.

When refilled, usually take it to 1 bar, when operating (hot) may reach
1.5-2bar.

If it is reaching 2 bar when operating, I'd consider adding an additional
expansion vessel.

Christian.