CH leaks

We have a problem with pressure loss in our central heating system. Topping up each day and loosing 1bar or so in a matter of hours shows something is wrong. Brit. Gas have said there must be a leak and they've got to the stage of suggesting taking up flooring to inspect pipes and junctions. This is getting expensive and disruptive! BG have a £1000 limit on their part of repair and making good costs. Have people tried:

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(There are others)

Any experience with one of these companies? Pin-pointing the leak position may save money in the long term, even though the survey will cost a few hundred pounds. I've yet to explore the home insurance angle to reclaim some costs.

Reply to
mechanic
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Have you checked that the pressure relief valve is seating properly? A common cause of pressure loss. Normally just turn the knob a few times with the system pressurised to clear any crud from the seat.

Reply to
Bob Minchin

Can you isolate sections by adding ball valves, then you could narrow down the likely fault area. But first off have you checked the obvious stuff like the pressure relief valve (which can and do leak after a time) Air bleed valve (mine is a brass pot on the pump) Pressure in the pressure vessel (if this has no air pressure then system pressure can go high and lose water through the pressure relief valve)

Reply to
MrCheerful

Yup this...

If you tie a sandwich bag (or similar) over the end of the pressure relief pipe outside with a rubber band, you will be able to see if any water is being discharged though that over the day.

Reply to
John Rumm

my leak was hidden behing a bed ! .....

Reply to
Jimbo in the near of Hawick ..

Yes, actually I had a bag over the condensate pipe all day today (with the boiler off) to check for leakage via that - nothing. The PSV was replaced last week when this problem first surfaced, and the washers and seating were perfectly dry. There must be considerable water being lost somewhere but no sign of it on the surface, around rads, hot water cylinder or boiler. The BG guy is coming next week to blank off the pipework in order to separate the boiler from the rad feed pipework. Not sure which is the most expensive outcome as apparently the boiler is now too old to have full parts support.

Reply to
mechanic

There is also the possibility of discharge from a joint into the earth, as we have suspended timber floor about half a meter off the ground. It is a lot of water as you say - hard to miss.

Reply to
mechanic

Condom.

Reply to
The Natural Philosopher

The pressure relief pipe would be the most likely, if your loss is from the condensate pipe then the boiler heat exchanger has gone, in which case it is probably time for a new boiler.

Reply to
MrCheerful

If you've definitely ruled out the pressure relief valve, it's got to be a leak under the ground floor boards. Half a meter is a bit of a squeeze, but you may be able to crawl under there to take a look. (Take a mobile phone with you, so you can call the fire brigade if you get stuck. That'll give them some fun!) You can probably get access via the under stairs cupboard without wrecking the downstairs floors. Do you know any small, slim, agile people, who aren't scared of spiders?

Or get one of those USB cams, but it will be very hard to spot what won't be much more than a steady drip of water. It'll just soak into the ground under the house, particularly if you are on sand.

Reply to
GB

send a small child down. When we bought our first house it needed wiring and my wife's youngest brother who was about 8 yo, thought it was great fun to crawl under the floorboards pulling cables.

Reply to
charles

Early last year our CH developed a leak from the body of one of the automatic air vents. Put some Fernox sealer into the system, and it resealed it nicely. Was intended to be temporary, but it was 18 months before I got around to replacing the AAV (did both for good measure), and the seal was still good. I reckon it would have lasted a lot longer, in fact.

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Might be worth a try if you're sure it's not the PRV.

Reply to
Chris Hogg

No drips from the condensation pipe over six hours or so, during which the pressure dropped by about one bar. Our British Gas 'engineer' suggested this to rule out the heat exchanger (apparently no spares of this model now available).

I'll check on the insurance cover tomorrow and explore the leak detection company options. Drilling holes in our Amtico flooring or ripping it up together with the plywood substrate doesn't appeal one bit. Re-instating it would cost a small fortune.

Reply to
mechanic

I exaggerated - it's really about 300mm. We have air bricks in the walls for ventilation - maybe the BG fibre optic probe thingie may spot a pool of water.

Reply to
mechanic

... snipped Our British Gas

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May not be relevant to your actual problem but BG are renowned for saying that spares aren't available when they often are. Bear this in mind if the problem turns out to be in the boiler and they recommend a boiler replacement!

Reply to
nospam

Is there no way you can at least peer under the floor with a torch and spot water?

Reply to
James Wilkinson Sword

Is that a euphemism?

Reply to
James Wilkinson Sword

no

Reply to
Jimbo in the near of Hawick ..

Even if the PRV is working properly and not letting by, you can still get a problem due to over pressure if the expansion vessel has failed or needs pumping up. However I would have expected that would have been one of the first things they would have checked...

Reply to
John Rumm

Note that the condensate pipe is quite a different thing from the over pressure relief pipe. (one would expect the condensate pipe to pass water periodically - but that is not water from the primary side of the heating circuit.

Reply to
John Rumm

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