OK, so I’ve got a faily bad leak in the central heating, but there’s no visible signs of it at all, apart from loosing all pressure in the sytem (1bar to 0bar in about 5hrs) so, there’s got to be a leak and I guess it’s under either the tiled kitchen floor, or under the solid wood floor in the dining / living room. Anything above this height should be visible in water damage etc.
So, I just got a quote for almost £600 for a thermal and gas leak detection and repair of the leak (mins re-laying tiles if req).
Seem steep, but saves pulling up all floors until it’s found. Sadly the insurance company won’t pay for track and trace, just any damage so it’s got to come out the back pocket hence asking the question. Anyone else had it done, had success or did you end up ripping everything up and finding it the old fashioned way? Anyone rented the equipment and done it themselves?

Mine wasn’t quite that bad but pouring that sealant stuff in sorted it…

Is it loosing the pressure while the heating is off.

If it only looses pressure with the heating on it could be an expansion vessel. Combi boiler have an expansion vessel which when it fails leaves no room for the expansion of the water when hot so blows the water out of the pressure release.

Just a thought always start with the simple options.

Tried two bottles, no differance. Wierdly when I got distracted re-filling, and it went to 3 bar, it held for a week until I bled through a radiator at which point it dropped (past where the bleed got it too) and carried on until no pressure again.

big surfer – I think so, but I’ll check as sson as I can leave the heating off (1yr old in the house, need to spend the night away so that I can leave it to get proper chilly. Not sure it’d be fair in the weather we’re about to have!!

what about the pressure relief valve (if it has one) on my worcester combi’s they often get stuck, easy to replace. Check the overflow pipe for wetness. Even a few drops will lower pressure significantly.

Had the Gas Man out yesterday to fix the same problem. As bigsurfer said it was the expansion vessel which has a bladder in to separate water and air. I think he ended up pumping more air into it and cleaning the pressure relief valve so it makes a proper seal when it shuts. To test it’s a boiler problem locate the central heating pipes (out and return), there should be an inline valve, turn these off with a quarter turn. Then repressure the boiler, locate the pressure relief outlet and see if water is coming out and if you’re still losing pressure. If it is, the good news is you haven’t got a leak, the bad news: you need to see to your old boiler..

Right, I’ll pack nipper off to the outlaws and try the above.
Failing that, no-one for a leak detection company?

the one that came out on a job that I was working on were utterly clueless and useless. And bloody expensive.

The bloke was pointing his thermal camera at the wall and ceiling despite me telling him there were no pipes in those areas!

its the exzpansion vessel/ prv// go out side with a balloon and put it over the little copper pipe that sticks out the wall turn central heating on full wack.. check it in an hour.. any water in ballon and its the boiler not yer pipes.. its the boiler in 50% of circs.. in the rest its at a rad valve or the rad itself..

Turn off boiler before you go bed,top up pressure to 1.5/2 bar then isolate central heating pipes,generally located under boiler ,then in the morning you will know if leak is on system or boiler

What boiler is it first off?

It’s a Ravensheat jobby, havn’t got the model type at work, but if you google shite, it’ll probably come up!

I’ll do the ballon thing tonight, but until I can heat the house a differnt way (and find a way to actually turn those two isolation valves (bloody installation!!) then I’ll have to wait for the next bit.

3 different plumbers have said it’s not the bolier leaking though and is a pipe, I’m struggling to see where that much water could be going to as there’s nothing visible, hence my under floor thoughts.

Thanks for the advice so far, I’ll get on it when I get home.

Is it a condensing Ravenheat?

dont do as peasant says great idea but your isolation valves with leak 9 times out of ten..

Fair comment totalshell

Does it happen all the time?

I have a simular issue, only when it’s cold the pressure drops, the water loss is from the overflow. No idea why but the system’s done it since new (there were other issues at the time and it wasn’t cold so it wasn’t sorted then).

I just top it up when the pressure drops (every couple of weeks in this weather).

Anyone know why?

Yes it’s a condensing one. Bag about to be tied over the outlet pipe, but it’s proper cold in the house so leaving the heating on to keep nipper warm so can’t do the isolating tonight (I take the point about the valves leaking, but it could be worth a go). Of course, I need to actually get to the valves, and the moron who installed it make that more tricky than a tricky thing!

Yes, it happens all the time, whether I top up when it’s already been on or not. So does it from cold as well as hot.

The really irritating thing was sitting in traffic watchting a young lady pull to the front of the queue on Yeti going on the Wednesday ride while I knew I was on my way home to wrestle with this little bugger!

If a condensing heat exchanger leaks internally, the central heating water will run down the condensate sump and out through the condensate waste. You’ll never notice it. Only way to tell us disconnect the waste and fill the boiler up when cold. See if the waste starts to run.

Ok, understand that, but how do I know which one the waste is?

I think some kitchen alterations are about to happen, if I cure it, all will be forgiven. If not, Mrs transapp is never going to forgive me!

Oh, and balloon is taped over the outlet. Should know in an hour…

Oh, and can’t thank you all enough for all the help. Sick of this damn thing now.

thats another alternative PS.. the ballon tricks favourite.. HT if your boiler ‘overflow’ actually the pressure relief pipework leaks when the boiler is cold and hot than the pressure relief valve is at fault.. simple fix unless its a new WB then its boiler off…

kids party ballons the central heating mans favourite tool alongside his exhaust gas analyser..

odds on the ballon having water in it.. 2/1? or evens.. dont froget to turn the boiler on.. max it up..

boiler on max, slightly overfilled (1.75bar) pressure should be dropping now, but I’ve been drooling over retro pictures of Tomac’s bike, not keeping check!

Going outside now

talking of Tomac is that kid eli tomac on the sx lites his son?

No water at all from the overflow pipe, but actually more than I would expect from the gas exhaust (enough to form an ice patch on the floor where it’s condensed and dripped).

Yes, it is Tomacs son. Talented family (although I think maybe a garage full of mx bikes gave him a head start!)

next tip than is PS’s when its off leave it an hour to see if water is coming out of the condensate..

after that on to peasants turn the boiler valves off.. while its off.. ( only the central haeting flow and return) and see if the pressure drops over night.. turn boiler off at fuse spur before doing any of this..

Right oh, any tips on how to find which one is the waste please? the out/return are faily obvious, but the others are a little more confusing (and I can only see a tiny bit of the pipes through a cut out in the splash back of a kitchen surface)

It’ll be plastic.

ah yes, there’s a plastic pipe in there. Thank you, I’m on it.

Something slightly odd last night, having a hunt around for where the plastic pipe goes into the boiler, firstly I found a small leak. Not where the waste pipe goes in, but on what looks like a copper box, with several pipes going into it, underneath the red (what I presume is) the expansion chamber. Very irritationgly, there was a wad of tissue under the leak that must have been seen by either or both of the British Gas Engineers when they’ve come around to look at the boiler (other faults, now corrected)
The second bit is that when I traced the plastic pipe into what loooks like the condensing trap (plastic vessle type thing, earthed with two white cables coming out a connection the top), the pressure in the system leapt to 3.0bar, and it’s stayed there overnight. ❓
I didn’t do anything other than move the connector on top of the condensing trap (assume this is the condensing sensor??), and not remove, just move it.
I’m now really confused, but it doesn’t look like it’s pipework….

This is the boiler

http://www.ravenheat.co.uk/pdf/manuals/CSI85A(T).pdf

From memory, those cables on the trap are wired to the ignition, and stop the boiler firing if the trap backs up. Nothing to do with pressure.

You shouldn’t really have your hands in there. Get a gas man in.

Yes I know I should get a gas man, but 3 have said there’s a leak in the pipework and I’m just not convinced. Glad I did go in as I’ve found a leak, obviously covered up by British gas (one put it there and one can’t not have seen the damp tissue…) so I’ll be calling to issue bollocking shortly.
Then I’m back to the original issue, only now it’s not loosing pressure….
Oh well quit while ahead and thanks again!