FOUND IT! Finding an underfloor leak

[MickyP10]

Hi

Have an underfloor heating leak in a five-year old bungalow and trying to find the best way of tracking it down. The (copper) pipes are under screed. System only seems to lose pressure when cold (or maybe it just loses more when cold), so my initial thought of a thermal imaging camera has been put on hold. They're expensive, too. Most of the rooms have laminate flooring, and this has a foam membrane/underlay which may contain damp in the screed, so damp isn't obvious on the surface. Either way, there isn't an obvious damp stain anywere.

Was going to get a pipe detector, purely to find the lines I should be concentrating on, but pretty sure they're not going to pick up pipes buried in screed. Would a damp meter do anything, aside from working out that the bathroom is damper than the living room? Would an infrared thermometer be better? Tried pressurising to 2 bar cold and having a shuftie and listening with a microphone and sound meter. Can't hear a thing apart from my stomach gurgling when I lie on the floor! I haven't but could try shutting the rads and pressuring to two bar to see if that helps.

Have gone to some lengths checking and replacing above-floor componets: TRV gland seals, pressure vessel pressure valve, have tried a leak sealer, etc. Now getting desperate!

I suspect when the heating's on (as it's been cold) the damp patch which is forming is drying out again. Would it be a case of leaving the heating off, keep topping up and try and exaggerate the leak so its origin is more obvious? Or should I move?

 

[gigz]

Try isolating as much as you can to try and narrow it down, also have you checked the P.R.V.

 

[MickyP10]

Got a new prv on order but outlet pipe is bone dry, inside and out.

Just shut off the rads and whacked a couple of bar in the system. Hoping something will show.

 

[heatingman]

sounds like a job for the cheap perfume.

 

[MickyP10]

Heard about that, and I'll try anything. Will the pong permeate the screed, though?

 

[heatingman]

If its a nice cheap stinky one yes it will, whack up the pressure after administering into system, and close all internal doors and windows. Sometimes helps to get a non-smoker to sniff it out, years off abuse kill the old nostrils. Used this method a lot, sometimes takes you to within inches of leak, othertimes just identified the room/area. Always saves time and money destroying/removing/digging in vain.
Takes a bit of explaining when I get home, "why do you stink like a brothel, where you been"

 

[WDIK]

If its a nice cheap stinky one yes it will, whack up the pressure after administering into system, and close all internal doors and windows. Sometimes helps to get a non-smoker to sniff it out, years off abuse kill the old nostrils. Used this method a lot, sometimes takes you to within inches of leak, othertimes just identified the room/area. Always saves time and money destroying/removing/digging in vain.
Takes a bit of explaining when I get home, "why do you stink like a brothel, where you been"

:lol

 

[MickyP10]

Do I run I just run it round for a couple of mins? Then shut down and up the pressure?

 

[heatingman]

No heat, just circulate around system, what type of boiler do you have.

 

[MickyP10]

Firebird S 90 oil burner. When the pump comes on the boiler does too.

If I turn the boiler off (at the boiler), and turn the system on, not sure whether the pump will run on its own. I suspect it'll be as dead as the boiler, though.

If I kept the rads shut (except the towel rail, as this is where I'd tip it in), so's it'd wizz around the pipework quickly, would it matter if I had the boiler on for a min or so? Don't really want to start hard wiring pumps, etc.

 

[heatingman]

keep it on low too wizz it round system, close any aav's.

 

[MickyP10]

OK, ta. Will try later today.

 

[MickyP10]

Found it! After lifting the kitchen tiles and digging up the boiler pipework, I pushed a a chisel through a pipe, causing another leak. After fixing that and buggering up the vacuum cleaner hoovering dirt and screed, oh and lifting the laminate floor in the utility room, I was walking back to the bedroom, barefoot and thought I felt a warm patch in the hall. Remember all of my floors are laminate.

Next day I lifted the edging strips from hall to bedroom, cut the foam membrane and levered up for a look and it was soaking. The membrane was holding the water beneath the flooring, so flooring wasn't opening up or distorting. Now ripped up half of the hall flooring and found a 12-foot damp stain! Currently trying to get closer to source.

Thanks to heatingman for stink test tip. I did run the pump for three or four mins with the stink perfume ('Madame'), but couldn't sniff much in the other rooms. Was only after when I refilled after going through the pipe that I discovered most of the perfume still in the towel rail. It's worth a go, though. My next step would have been a thermal imaging camera, and they must be £250-ish per day.

 

[ChrisR]

Any other Fragrance recommendations?
Who remembers 'Enery Cooper and the Great Smell of Brut?

 

[MickyP10]

Hai Karate?