New (quality) build: Is central heating piping pressure tested?

I don't have a problem. Am just curious.

In my previous ex-LA house the central heating pipes were mainly visible along the skirting boards and were also routed upstairs under the floorboards. It was possible therefore to inspect the piping for leaks quite easily.

In my current house, built in 2004, all piping is hidden under the tiled floors. Only the little stubs that pop up through the floor tiling where the radiators connect are visible.

Question: When such piping is installed, is it pressure tested in some way? I could imagine discovering where a leak is with hidden piping could be a very costly business. One would have to lift some or all of the floor tiles for a start.

MM

Reply to
MM
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Pipes under floorboards is bad enough but I never did like the idea of under tiling ...

Reply to
Usenet Nutter

Hmm, if it's rads rather than UFH, could they not have used flexible pipe and slid it into larger pipes embedded into the floor? That way if something does ever c*ck up it might at least be possible to fix without ripping the whole floor up...

Reply to
Jules

The Water Regulations (or rather WRAS, the advisory scheme) have a recommended procedure for pressure testing of supplies. ISTR though that although some sort of pressure testing is mandatory in commercial environments, it isn't on domestic installations.

Building Regulations mandate pressure testing of sewers, but not water supply IIRC.

However pressure testing is widely used by professional plumbers, and particularly for UFH.

A suitable gauge for dry air testing with a 15mm push fit on it is now about 30 quid

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use one along with a car tyre footpump. It's not foolproof. I just had to tackle an inaccessible joint with a very slow drip on it, that didn't show under air testing. (My one and only poor solder joint in a thermal store installation). But it will show most problems.

Possibly the much higher pressure, professional test kits will show even the slightest leaks up.

(As an aside, when I used to work on ultra-high vacuum systems years ago, mass-spectrometer gas analysers had just become available. You connected up your vacuum system to the gas analyser, then went round squirting helium gas at each joint, until the analyser showed up that the gas had found a way inside the vacuum system - I don't think plumbers have these *yet*)

Reply to
dom

It should be. TBH if the mains is about 3.5 bar I usually just crank it up to mains pressure and leave it for several hours.

Reply to
YAPH

Dry pressure testing works very well on systems which have never had water in them. Can be much more touch and go on a system once it's been wetted. Water can block leaks for long enough that you won't find them. Depends on pipe layout and nature of the leak.

Reply to
Andrew Gabriel

It's not UFH. It's standard copper tubing feeding radiators. I am assuming that enough care is taken during the pipework installation to give the pipework the longest life possible. As I see it, the ONLY long-term threats to the pipework could be: structural movement, e.g. earth tremor, settlement; or freezing; or corrosion. Otherwise the pipes should surely last indefinitely without risk of leaking?

In my previous house, if there had been a leak it would have been relatively trivial to repair, given the visibility of and easy access to the pipework. This wouldn't be the case in my present property. By the way, if I had the choice, I'd rather have the pipework on the surface! Make it a design feature, perhaps. My next property is going to be really old and I shall make a point to find one with open pipework.

MM

Reply to
MM

When installing UFH I decided to invest in a wet pressure tester. It cost =C2=A390, but I thought that cheap compared with a leak after screeding. The procedure suggested was to fill the pipework with water, connect up the pressure tester and take it up to 8 bar. Leave it for 30 minutes, if no pressure drop, reduce the pressure to 6 bar and leave it a further 24 hours. In fact I left mine at 6 bar for over a week while the screed was laid and set - to protect against labourer's boots. Overkill, yes, but the peach of mind....

R.

Reply to
TheOldFellow

The main "long-term threat to the pipework" will be from the constant expansion and contraction of the pipes in normal operation as the boiler starts up and circulates the hot water, forcing the pipes to expand, then stops and allows the pipes to contract as they cool down.

It is extremely rare for plain pipe to leak. The leaks will normally come at joints and fittings where the expansion and contraction of the pipes place quite high stresses on both soldered and mechanical joints.

There will also be some corrosion between the dissimilar metals used, although this can be kept to a minimum by use of a corrosion inhibitor in the system.

Reply to
Bruce

Only a knob tests systems with air. It goes bang if it fails and bits of metal & plastic may fly around at terminal velocities, i.e., it will terminate you if you're in the way.

One of the aims of the test is to force any weak joint to fail, then it is not a good idea, i.e. a system failure under a pressure test is a sucessful pressure test. . Since many fittings are made by no-name manufacturers in far eastern sweat shops with no quality control, putting such fittings under air pressure really is not a good idea.

The HVCA recommendation is to test with water if at all possible. If pneumatic testing is unavoidable. then the recommendations are onerous, e.g., evacuate areas under test, no more than 0.5 bar pressure, tie down hoses, calibrated pressure gauge, board over windows, etc.. You deviate from these recommendations at your peril (and you needlessly endanger anyone in the vicinity).

Water testing will show a leak far quicker than air. A competent plumber would have no qualms in filling a new system with water because he should be confident that there will be no leaks.

Helium leak detectors are used but only by leak detection contractors.

Reply to
Onetap

Bad assumption. Time is money to builders. To do things with full care and attention to detail takes lots of time...

Reply to
Dave Liquorice

This immediately makes me ask whether the pipe runs under the flooring are continuous without joins?

MM

Reply to
MM

Which is, I am given to understand by the neighbours, what happened. These houses are NOT the bad kind that feature on those "Watchdog" type programmes on the TV. They were built by a local builder who is currently building other houses in the immediate area.

MM

Reply to
MM

No, mine have started to leak after ~17 years :-(.

Reply to
Chris Bartram

Yep - that's the sort of thing you'll see in a DIY install. My dad did exactly this when planning the pipework for his solid floor extention. All the pipework runs are short enough that there are no joins under the floor. (Mind you, that is easier with a single-pipe system.)

Reply to
Andrew Gabriel

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