I have been in my house for a year. During that time I have had no problems with the boiler which is a combi for my hotwater and CH. I joined Homeserve as they give you a free service once a year and yesterday a Corgi engineer came out to service it giving it a clean bill of health.

The next day my pressure was at 0 and I could not use CH or hot water. My CH has been off since May and the only reason I knew it was not working is because I tried it before I saw the pressure was at 0. When I saw the pressure was down to 0 I added more water from the filler loop, taking it back up to 1.5. I then tried CH and hot water and both were working again and were stable. However, when I turned off the CH, the pressure dropped again to O. I again filled the boiler to 1.5 and tried the hot water. It is stable while it is running but after switch off over the course of about 10-20 mins it drops to O. I phoned up Homeserve and they sent out another engineer from the same company and he refilled the boiler and ran the hot water and again the pressure valve was stable. The hot water was turned off and he waited for a while but had to go to another job. After 10-20 mins the pressure then dropped again to 0. I phoned them back and they are now saying that I must have a leak but there were no problems yesterday!! I have looked over the whole house and can find no leak(unless under floorboards or in walls) and it must be a massive leak to take 20mins to empty boiler!!!

After he had gone I refilled the boiler and ran the CH for 2 hours with no drop in pressure at all. Even when running the hot water at the same time there was no drop. However, as soon as it was turned off the pressure went to 0 again within 20 mins.

Please help. Basically I need to know could the service engineer have caused this by knocking something in the boiler? He gave it a full service but did not touch anything else.

I have looked on DIY sites and the options are:

1 A leak - I have checked and cant find one.
2 Pressure relief Valve - have checked this and no water coming out.
3 Expansion vessel - don't know anything about this but could this be possible?
4 Air in system venting through automatic air vent - could this be possible?
5 Diverter or diaphram?

Are any of these possible. I have checked the first two. Would really appreciate any advice at all. Thanks.

Lizbet30, August 2008

NightmaThis is becoming a nightmare. I did not touch anything after the service engineer (from original company that did service) left yesterday so pressure at zero. Last night I heard gurgling in the radiators even though CH off and pressure zero. The only way we could sleep was if I closed all the radiators on the top floor. I assumed this was more evidence of a leak.

The plumber (employed by Homebase but new company) came out this morning. He filled up the filler loop and ran hot water. This time there was no pressure drop at all. I explained all the pipework but he said if there was a leak then there was no evidence and he would have expected some seepage even if it was under the kitchen floor(cellar doesnt run under that) and suggested that if something did pop out it has popped in again. We then tried CH and it now doesn't work at all. The odd thing is that it heats up above a section of pipe just down from the boiler but then doesn't carry on into the system. The plumber told me that he cannot do anything if there is no evidence of a leak.

My issue is now that I am worried that the engineer yesterday turned a valve to the CH pipe and did not turn it back on - could that be the new issue? Could that be now why there is no pressure drop but the central heating pipe is hot straight under the boiler but not hot. We now have hot water working pressure is stable but no CH!!!!!! I phoned Homeserve and then are now sending a new company boiler engineer out and I am waiting on the call now.

Halfway through the call the new company rang and cant see me till Tuesday so have now rung Homeserve back to see if I can get someone else. I have now phoned Homeserve again and they are trying a new company.

Just to schedule the issue.

Before Tuesday 19th August no issue with boiler for a year (moved in July 2007). I tuned off CH in May but prior to that no issue. Service engineer came to service the boiler and gave me a certificate to say all was fine with boiler.

After Tuesday 19th August next morning we had no hot water and I noticed pressure zero. I used filler loop and then both CH and hot water working fine but after a while pressure went to zero. Phoned Homeserve and they arranged for someone from the company to come back out.

I kept using the filler loop to put in water and pressure kept going to zero but both hot water and CH were working when some pressure remained. I have detailed all the other issues in earlier posts.

Wednesday 20th pm engineer came out from company that originally did the service and could find nothing wrong and the pressure seemed ok. 20 mins after he left it went to zero. I then phoned Homeserve and they said they would arrange for someone from the company to come out again. During this time I had phoned the company direct as I had a mobile number. The person on the phone had practically accused me of lying about a leak and that it was too much of a coincidence that this had happened at the time but this was not the case as I had no issues before this.

Thursday 21st same engineer as Wednesday came out and thoroughly checked boiler and said expansion vessel ok and PRV. He said he isolated the boiler and that was definitely fine and I definitely had a leak most likely under kitchen floor. I left everything as it was as Homeserve arranged for a plumber today.

Friday 22nd a plumber from different company came and have stated above in this post what is the situation now.

Do you know what on earth could be going on? Am starting to be at wits end. The only reason I can keep being at home is that I am a teacher and on summer holiday. I have had to cancel going away to see relatives but the new term will start in a week and will have to go back to work then. I have now had issues for 4 days. I did say to the service engineer yesterday about the expansion vessel but he said it was ok.re continues!

Lizbet30, August 2008

Latest update!!!
The Homeserve engineer has just left and thoroughly checked the boiler. I explained about having to top the boiler up 7 times yesterday and he isolated the boiler and found it was secure. Therefore he says it can only be a leak but yesterday at least 10 litres of water must have come out as I kept topping it up when boiler pressure went to zero so the leak must be massive.

It seems probable that because we had no issues before the service man came on Tuesday and the CH has been off since May, when the original he came out to check the boiler and pressure it must have either started a leak or popped a join in the pipes. The issue is now where this massive amount of water is since Tuesday as there are no visible signs. Our house is an old Victorian terrace and the boiler is in a bedroom on the first floor. The pipes go down into the floor and into a boxed unit in the lounge below next to the fireplace and into the cellar, being open in the ceiling (we have not done up the cellar so easy to see in the joists. There are no leaking pipes in the cellar and no pools of water. I have checked all the ground floor ceilings and all the walls and radiator joins. He thinks that the solution may be the kitchen extension put on the house at a later date so the cellar does not run under there. This means that they are under a concrete floor which is covered with slate tiles. He thinks that a joint may have popped under the floor on Tuesday. Does this sound right?

They are going to now get a plumber out to check this and he says they should isolate the pipes going to the kitchen first and check the pressure in the system which will let them know if that is definitely the issue. What I don't understand is that there are no signs at all in the kitchen floor (or ceiling) of water seeping upwards through the floor. Would the water just go into the ground then? The boiler has been topped up at least 10 times since Tuesday and so we are talking a lot of water. Would appreciate any comments. There were no issues with the CH from July 2007 when we moved in until May when turned off and we have had hot water all summer with no issues until Tuesday. The only time I have ever had to top up the pressure was when I first moved in a year ago as I noticed it was at .5 and then no issues until after engineer came on Tuesday. Thanks.

Lizbet30, August 2008

you can asscertain where wether the leak is on the system or in the boiler by re-filling, and closing the heating isolation valves on the boiler. leave it a hour or whatever and see if the guage moves. if it does, its the boiler, if it dosen't, open the valves and see if the guage moves. if it does it's the system. (Providing the guage is on the boiler and not pipework?

steve, August 2008

Thanks for getting back to me. They are going to come back today so will see what happens. If it is a leak it must be massive as I filled up to 1.5 from empty 7 times yesterday and there is no evidence of water anywhere. The pipes go under the floor and are on the ceiling of the cellar and I can see no dripping and the walls show no discolouration. An odd thing happened this morning when I again filled up the boiler to 1.5 and turned on the heating. This time it went up to 3 and the PRV did start venting outside. I needed to bleed nearly 4 litres out from a radiator before it became stable at 1.5. It then stayed there. When I tuned off the heating it stayed at 1.5 for an hour. When I turned on the heating again though. It went down to 0 again. Am going to suggest The diaphragm i Expansion vessel is perforated to them. The thing is if I had a leak I would have known about it. I have never had to top up the filling valve before except when I first moved in. It does suggest the service caused this.

Lizbet30, August 2008

There are only 3 things that could cause this.

1)Quite a large leak
2)Pressure relief valve passing
3)The diaphragm in the Expansion vessel is perforated

If there was a leak or the PRV was passing this would almost always show up whether the system was on or not.
You seem to have ruled out 1 and 2,therefore I would suggest No 3.

Although 20 mins to go to zero seems excessively quickly.You have a Homecare scheme,therefore you should DEMAND that they return to at least find out what the problem is,after all it is highly likely that there engineer caused the problem,regardless of what he says he did not touch.

Gasman, August 2008