Slow Leak in Heating System and a bit of a Plumber Challenge

Postby Heptagon7 » Tue Dec 26, 2017 4:04 pm

How does the plumbing trade identify a slow leak in a domestic heating system? My system is a Combi fed closed system on two floors. The Worcester boiler is at the high point of the system. CH pressure at off temperature drops slowly over a few weeks. When it gets into the red I re-pressure with the filling bridge to around 1.2 bar by a few litres( from my estimation).When it drops too low, pump gets a bit noisy, radiators go cool and pump has shut down on occasion, probably due to air accumulation in the boiler. Domestic hot water is fine.I suspect a slow leak in the CH pipework under the floor somewhere. No leaks or damp areas are evident anywhere so likely it is evaporating. Low pressure while the house is unoccupied could cause me a problem, plus any inhibitior is being diluted. Are there any methods to identify where the leak is without pulling up carpets and floorboards in 7 or 8 rooms?
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Simply Build It

Postby Dunny79 » Mon Jan 22, 2018 9:20 pm

Hi, I’m no expert by any means, just an enthusiastic ameatuer, but you can get a leak sealer that you inject into you’re system. It seals small leaks. Also worth trying, does the central heating pressure on the boiler creep up to 3 bar. If it does you could be losing water from the safety blow off which opens up at 3 bar. If this is happening you’ll probably have no pressure in your expansion vessel. It’ll be a red vessel either on the boiler or near by. This should have 1 bar of pressure in. If you’ve got a foot pump you can check this yourself. If it doesn’t pump up then the diaphragm inside will have perforated and you’ll need a new one. Hope this helps
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