Ravenheat Boiler Issue - Loosing Pressure

Hi,

I'm a 1st time poster, but have looked on the site quite a lot in the past for answers. My problem has recently only just started but I am lost as to what it could be. My boiler is a Ravenheat CSI 85T HE which was installed in April 08. On our last boiler the pressure used to drop very slowly and over time the boiler became noisier and noisier until it stopped working, our plumber said it wasn't worth fixing and just wait until it expires and get a new one.

After getting the new one installed, we had a couple of issues with leaks from the pipework going into the boiler. Everything seemed ok with the boiler, but we were only using the boiler for hot water as there was no need for the heating to be on as it was May and summer was allegedly on the way. Last Friday, we could hold off no longer and had to put the heating on, everything was fine all the radiators got warm and after about an hour I switched the heating off. About an hour after this I was in the kitchen and noticed that the pressure in the boiler had dropped from just under 1.5 bar to 0.5 bar, then on the Saturday morning the pressure had emptied down to 0 bar. My 1st thought was that we have a leak somewhere in the central heating pipework downstairs, my reasoning behind this is that if the leak was upstairs I would have seen the tell tale water marks on the ceiling which I didn't.

I then looked on the forum to see if I could see something similar to my problem, and on searching I found something about the divertor valve and how to test for this, by putting a bag on the pipe and if it leaked you would be able to tell from the bag been wet. I did this test and the bag stayed dry, so this is why I am assuming that I have a leak on the pipework downstairs. I filled the boiler up at night when I did this test to 1.2 bar and the pressure didn't change but the following morning the pressure had dropped 0.2 bar to 1.0 bar. Tonight I am going to have a look under the floorboards to see if there is an obvious leak, but our trap door has been nailed shut and I broke my claw hammer trying to get the nails out.

Sorry for rambling on, but i hope I have explained everything clearly so maybe you could point me in the right direction as to whether you think I have leaky pipes or maybe something wrong with the boiler.

Thanks in advance

Just to update, I filled our boiler up again to 1.4 bar and put the heating on, all the radiators became hot, but it lost about 0.1 bar of pressure with the heating on, I then turned the heating off and within half an hour the pressure had dropped by about half to 0.7. This morning there was no pressure in the boiler.

I have spoken to the people who installed our boiler and they have said to fill the boiler up to 1 3/4 bar, then bleed the radiators put the heating on and see if it drops pressure. They said to do this for a couple of days and if the problem carries on then they will come and have a look at the boiler. My only concern is that if there is a leaking joint then I am just adding to the problem of water collecting somewhere.

Does this sound right what our plumber has said, I tried looking under our floor through the trap door, but it wasn't a trap door it was just a cut out for a mat in front of the front door. Does this mean that I will have to take floorboards up to see if the pipework is leaking.

hi it does sound a bit like the expansion vessel has not been set up properly , i think they should come back and discharge the system and check to see what pressure is in the vessel it prob just needs pumping up a bit, what can be happeng is that the diaphram is sloppy because of lack of air pressure inside then when you up the pressure and the heating comes on it expands ok but when it all cools down the pressure will go down to almost zero or less because the water shrinks and then allows the diphram to go loose again
wih the correct pressure in it should stay stable

there can be air still in the system but it should dissipate through the auto airvent on the system so if what they have told you to do does not work get them back