Hope you can lend some advise, I recently had the above boiler installed and I am only running 4 radiators at the moment while I renovate the flat, I am using HEP pipes and there no joins on this under the floor nor is the bathroom finished so no hot water just the 4 radiators (the others are capped off)

The issue is that when i pressurise the system to say 1.5 bar within an hour or 2 this has gone down to well below 1 bar and into the red at nearly 0, re-pressurise and the same happens.

if I then switch off the boiler at the mains it goes up to around 0.5 or just under 1 bar on occassions then when I turn it on its drops to almost 0 again yet all the radiators are on, working fine and are hot over the whole area of the radiator.

I have only done this a few times since install as I live in an upstairs flat and I am concerned that it could be a leek, however per above there are no joins and I cannot locate any leeks so far but as yet I have not lifted the floors which will be a nightmare.

Assuming that I have no leeks is there anything that I can check or test on the boiler before I commit to doing this, as if I have to keep filling then it must be going somewhere???

I have had a quick look outside but can see no signs of water from the pressure release valve which I assume is the pipe on the bottom right going outside however this could be tested further.

On a side note with this style of boiler should the pressure remain constant if only 1 radiator was connected? it would be easy to lift the hall floor to see the pipes for that radiator and I have easy access to the main junction where all the pipes meet, so I thought if I disconnected all the others and put some loops in place and only had the 1 one radiator running in theory I could work out if it was the boiler or a leek somewhere else and work my way round each radiator that was connected without the need to lift the floor??

I haver also heard others having similar issues and that perhaps it could be an expansion vessel issue??

Lee Robertson, August 2010

Mine is doing exactly the same no leaks on pipe work PRV replaced twice but still loosing presure. Two pipes outside one is PRV vent other unsure but both drop water continuously. Any more ideas ?

Rob, March 2012

I had laid the pipes for this and there are no joins, each pipe was carefully run and fixed in place to minimise movement then I had an engineer install the boiler, I have him coming back on Monday to check so will get him to try this

Thanks

Lee Robertson, August 2010

I'd be VERY suprised if it was an expansion vessel problem seeing as you've just had the boiler fitted.

As you intimate, the water MUST be going somewhere, try isolating the flow and return CH valves overnight with pressure in the boiler, this will indicate if it's the boiler or the system (ie: pressure stays normal it's the system).

If, as you say, you've just had it fitted, shouldn't the installer be coming back to check it out?
Or is this a self install?

Carefree, August 2010