0333 567 2639

Underfloor heatingFloorboards

Heating leak under a wooden floor in a home with two underfloor manifolds, Beccles

With fourteen underfloor zones, the heating was the natural suspect. Testing each section showed the underfloor circuits were sound and the leak was on the radiator pipework.

Narrow strip of oak floor lifted to expose white plastic pipework underneath
One strip of wooden floor lifted where the methods agreed, Beccles job.
Location
Beccles, Suffolk (NR34)
Property
Residential property
System
Outdoor oil combi boiler, two underfloor heating manifolds (eight and six zones), hot water cylinder and eight radiators
First sign
Heating losing pressure again and again, no water visible anywhere
Engineer
Ferenc Gulyas, ADI Leak Detection
Outcome
Leak found on radiator pipework; fitting replaced; retest passed

What was happening

The system is large: an oil combi boiler outside, two underfloor heating manifolds in a utility cupboard serving eight and six zones, a hot water cylinder and eight radiators in the bedrooms.

It kept losing pressure. The floors are mixed and there was no visible sign of a leak anywhere.

How the leak was traced

  1. Pressure testing by section

    The system was split into sections and each tested with water. The underfloor heating circuits passed and the boiler passed, leaving the radiator pipework.

  2. Isolation valve

    A 22mm full-bore lever valve was fitted so the manifolds could be isolated from the radiator circuit for testing.

  3. Tracer gas

    Gas in the radiator circuit was picked up by the detector in the corridor area.

  4. Acoustic listening

    Narrowed the corridor reading to a specific point in the living room.

What was found

The customer was told the suspected spot and what lifting the wooden floor would involve before any boards came up.

The floor was lifted at that point and a cracked push-fit fitting on the radiator pipework was found.

What happened next

The fitting was replaced with new Hep2O fittings, the system passed a pressure test and inhibitor was added.

Rule the underfloor heating in or out first

Testing the manifolds on their own showed the underfloor heating was not leaking, which saved a search across fourteen zones. Only one section of wooden floor was lifted.

Underfloor heating leaks: the full guide.

Photos from the job

  • Two underfloor heating manifolds with pumps and an expansion vessel in a utility cupboard
    The two underfloor heating manifolds.
  • Two pressure gauges on a test rig set up on a kitchen worktop
    Testing the system section by section.
  • Tracer gas detector with a probe lying on a wooden corridor floor
    Tracer gas detector in the corridor.
  • Finger pointing at a cracked white push-fit fitting under the floor
    The cracked push-fit fitting.

Case published by ADI Leak Detection. Photos taken by the engineer during the investigation.

Similar jobs

All case studies

  • Nottingham, Nottinghamshire. Underfloor heating, Screed floor

    Leak in underfloor heating pipes under new screed

    Acoustics and tracer gas were both misled by the way the pipes were laid. Warm water and a thermal camera showed the real pipe route and a faint mark at the leak.

    Leak located; repaired by the site plumbers

  • Battle, East Sussex. Underfloor heating, Screed floor

    The underfloor heating was not the leak

    With underfloor heating everywhere, the heating looked like the obvious suspect. Testing each supply in turn showed the leak was on a hot water T-piece behind a boiler room wall.

    Leak found on the hot supply; fitting replaced; retest held

  • Marlborough, Wiltshire. Underfloor heating

    Split plastic heating pipe buried in the floor

    The circuit would not hold any pressure. Air at 2 bar could be heard escaping through a wall, and acoustic equipment followed it to one corner of the room.

    Leak found; temporary repair; part re-run in copper

Call 0333 567 2639

Mon to Fri, 7:30am to 6:30pm