Looking for a leak

[Tim Lamb]

Umm. I suspect the valves on the filling loop are small bore leading to lots of noise.

You could unhitch and fill a container to get an actual.

Nevertheless, it does sound to be a significant amount of water going somewhere. I thought I had fixed mine when an auto air bleed literally fell off the attachment thread! Pre-fixed to the manifold so likely transport or installation damage. However, the system has now gone back to losing a *needle thickness* per day with no visible signs. Fully carpeted/tiled. Clearly with a manifold system I can isolate sections relatively easily when the Tuits line up. Meanwhile my guess is the screed over block and beam where a screeders shovel may have damaged a pipe and any subsequent leak invisible.

[Peter Parry]

I had a similar problem with a boiler with an aluminium heat exchanger corroding severely over time (Only about 10 years). Found where the problem was when one day it was all quiet in the kitchen and I heard the trickling water out of the condensate drain when the boiler was off. (I have some interesting photos of the dead heat exchanger if anyone wants some teaching material for plumbers.)

[DerbyBorn]

The filling loop will sound like it is passing a lot of water - but it is pushing against some back pressure.

[Robin]

Water meter? Ours has a 1 pulse/litre which would give a cross-check when averaged over a few days.

[John Rumm]

They are typical service valve size. When fully open the fill runs quietly.

Indeed I could...

Although the exact quantity in this case is not really the problem!

Yup UFH with a leak can be a right pain to fix.

[John Rumm]

No meter. I could unhitch the end of the filling loop hose and time it into a container if I wanted. However that does really seem to be focussing on the wrong problem.

[John Rumm]

ISTR a recent BigClive video on YouTube where he dissected a bit of pipe he cut out of his system that had sprung a pinhole leak. There were clear spots of corrosion inside the pipe where it was thinning.

Yup, here it is:

[John Rumm]

Its still got a 4 - 5 bar advantage over what is in the system (system pressure say 0.6 bar when I start refilling, mains pressure 6 bar).

[Thomas Prufer]

"fluorescein dye" in eBay... coupla quid, it's a orangey yellow.

A very very little goes a very long way! Found on eBay: "Typically 1 gram of fluorescein LTC powder will successfully colour change 1 ton of water."

Thomas Prufer

[Robin]

I just thought that if it turned out to be a lot less then a couple of litres it'd be less to worry about. Anyhow, I realise now a check on the amount is probably a lot easier: note the pressure before filling; then after filling drain into a container to get back to the initial mark.

[John Rumm]

A leak into the combustion chamber is possible. The outside however it spotlessly clean.

I will introduce a pressure valve into the pipework separate from the boiler's internal one, then I can isolate the boiler form its pipework and see if I can eliminate one or the other.

Already tried that.

Its not usually off for long enough at this time of year.

[John Rumm]

That would work (although I would need to drain from elsewhere, since the filling loop connection has a non return valve on it).

[John Rumm]

Ta, ordered some...

[Terry Casey]

Fill plastic bags with cold water - possibly place in the freezer for a while to ensure they are really cold - and hang/place them anywhere that the water vapour might escape and watch for tell-tale condensation

[Cynic]

I had a leak in a pressurised system in a 3 storey office block in Leeds. Same problem and couldn't find it so I injected a couple of containers of Fernox MB1. A couple of weeks later an unusual smell was reported in a small office in the ground floor. The leak was a weeping screwed ms elbow joint under the floor below the radiator. It was resolved by freezing, stripping out and reassembly using hemp and bosswhite. End of problem.

[Mr Pounder Esquire]

Snip. Not being rude. I was losing water. The loop valve was not turned off properly, even though it looked okay.

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[Tim Lamb]

Further news on my leak.

Isolating the floors showed the leak was upstairs! Slight wet patch showing below the manifold cover.

Water drip from the *plumber fitted* mixer valve! Basically the threaded spigot on the valve was too short to seal against the fibre washer inside the 22mm coupler. The joint was garmed up with plumbers mait.

Agricultural solution plus lots of ptfe tape...... we'll see how it goes.

[Roger Hayter]

Could you just saw a few mm off the nut?

[Tim Lamb]

Umm. That is where the spanner flats are. I actually turned a brass insert sleeve so that the thread bottoms. Not intended to be a seal but to load the taped threads and stop the joint bottoming on the body of the valve.

If it leaks again I'll buy a second fibre washer.

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[misterroy]

Yes, that is where the pinhole leak was in my hot water system. In a wall cavity, where the pipe went from vertical to horizontal. The water was spraying towards the outside and draining freely leaving no mark.