Problem with central heating - Advice Needed

[thames]

Hello
Hope someone can give me some advice on a problem im having with the central heating in my flat.
I have a Glowworm 18si fanned flue system boiler with 5 radiators. Over the past year I have had a problem that the boiler keeps losing pressure going to 0.6 where the red light will start flashing and then continuing to go to 0.0

It started almost a year ago and would lose pressure gradually over a couple of weeks but got quicker with time. We had a plumber come round and he fitted a Presure release valve which seemed to stop the problem for a couple of months how ever the problem eventually came back and slowly got worse.

We have had a couple of different plumbers round over the past couple of months and most recently had someone from British gas come round. He said he thinks it is a leak in the pipes somewhere and flushed the pipes with some filler. This has not helped and the system can now go from 1.8 to 0.0 in as little as an hour.

If the central heating is turned off but the hot water left on the boiler maintains its pressure, recently as a test I turned off each radiator individually at their bases and then turned the central heating on. this caused the boiler to lose pressure very quickly.

Obviously if this is a leak it will mean pulling up carpet and wooden flooring in my flat which I would rather not have to do not to mention drilling into the floor to get to the pipes is there anything else that would cause this problem. my flat is on the 3rd floor of a 3 story block and i have had no complaints from anyone below about leaks or ceiling stains from above so cant understand where the water could be going if it was a leak.

Thanks in advance for any help you can give.

 

[Jimbob]

expansion vessel been checked?

 

[gazleeds]

this sounds like the expansion vessel get a good local plumber to inspect the system for you

 

[payney1974]

As said already expansion vessel............. Simples.

 

[thames]

Thank you all for the quick replies. Would the british gas enginier not have checked the expansion vessle or is it something that you cant check and must just replace and hope for the best?

 

[moony]

theres a valve on the expansion vessel, press it see if water is present, not a job for you though matey get a reliable plumber (local) bg are more or less a sales pitch, he should of checked but probably didnt and you prob got charged 100 quid for something you could of easily done yourself for a tenner (leak sealer)