Heating - Britony Combi 80 - Losing Pressure

I have a Britony Combi 80 - made by Chaffoteaux at Maury.

Well I noticed the water pressure was slowly going down, so I refille as normal - via a metal hose under the unit. Then I decided to bleed the rads (upstairs had more air than water i them air!), then I obviously saw the water pressure drop rapidly an refilled until it behaved as normal...

Since then (a week ago now) I have seen the pressure drop to zero within 2 days. The is no *obvious* leak, there have been no changes, except I hav bled the rads.

Am I missing something here?

We have had to to have the mechanical peice (I know not the name) tha switches between service to the rads OR the hot water replaced *every year for the last 4 years! Yes the system is only 4 years old!

Thanks, HotSho

-- HotShot

Check a couple of things

2/What happens to the pressure when the system is hot? Does it go u above 2.5 bar?

post result and we'll talk through what to do next

-- Paul Barker

Thanks Paul,

1. The pressure relief valve (identified using the manual) is fine (th combi is located in the corner of the kitchen). So drips, drops o anything else.
2. When we moved-in the pressure always dropped down to 1.0 bar whatever you filled it up to. Now the pressure drops half a bar ever day. If the boiler is off, there is no change in the pressure. When i is on low the pressure drops half a bar every day, the hotter th radiators, the faster the drop in pressure.

I know this shouldn't have anything to do with it, but...the LC display has failed, I can just make out it trying to show the time...

Cheers, HotSho

-- HotShot

The pipe from the pressure relief valve goes through the wall t outside usually, it may alternatively have been run to the kitche waste in your case. Anyway you are to find the end of it and obsevr for water coming out of it no matter how small an amount.

Because you say it looses pressure when it has been on, I suspect tha it may be your expansion vessel. These are charged with air t something between 0.5 and 1 bar, quite typically they are 0.7 bar. I this is the cause of your problem either the air has escaped or th bladder is burst. There is a Schareder valve on it, depress the needl briefly, if water comes out you need a new expanshion vessel, if not get a bike pump, let all the air out, Read the pressure guage, pump u the vessel with the bike pump until the pressure guage shows a additional 0.7 bar

-- Paul Barker

I eventually got away from my PC...

The pressure relief valve outlet pipe is dripping, alot.

I have called an engineer out - If it's something simple I can do it but I doubt it.

Any ideas on the potential fault?

I don't want to get ripped-off by the engineer, unless the fault can b

Thanks for your help, HotSho

-- HotShot

If it only does it when the boiler is running you have expansion vesse problems which I've detailed above. If you were competent to fix i yourself you'd have understoof that, so good idea to get th professional in.

Pau

-- Paul Barker