Central Heating Leak Detection in Southampton

Symptoms

The property in SO18 is a large detached house served by a system boiler on the ground floor, with a hot water cylinder on the first floor. The heating system had been losing pressure, indicating a leak somewhere within the pipework — but with no visible signs of water on the surface, the source was not immediately apparent.

Because the system spans multiple floors and the pipework runs beneath floors and through walls, pinpointing the origin of the pressure loss required specialist internal leak detection rather than a visual inspection alone. With tiled kitchen floors and concealed underfloor pipework, any leak in that area would be particularly difficult to locate without dedicated equipment.

Thermal imaging gave an early indication of an anomaly in the kitchen in front of the fridge freezer, but further investigation was needed to confirm the exact source and avoid unnecessary disruption to flooring.

Methods Used

This internal leak detection job required a staged approach, working through multiple methods to narrow down the leak location without causing unnecessary damage. Thermal imaging identified a thermal anomaly in the kitchen, but damp meter readings across that area returned consistently low results, meaning the leak had not yet saturated the surrounding material to a detectable level.

Because standard moisture readings gave nothing away, tracer gas testing was used in two stages — first at 1 bar for 60 minutes, then at 3 bar. The higher pressure run produced a positive detection in the corridor under the stairs, and an endoscope camera was then used beneath the floorboards to trace the leak back to its actual source: a faulty push-fit fitting beneath the tiled kitchen floor.

The tracer gas had migrated laterally and surfaced away from the leak point, which is why the kitchen itself showed no gas reading at the lower pressure.

Investigation Process

1. 1
   Thermal imaging survey

   Thermal imaging was carried out across the property and identified a thermal anomaly in the kitchen floor in front of the fridge freezer, flagging it as the area of interest.

2. 2
   Damp meter survey

   The kitchen area was surveyed with a damp meter. All readings came back low with no elevated moisture identified, indicating the leak had not saturated the surrounding material.

3. 3
   Tracer gas test at 1 bar

   The pipework was cleared using an air compressor and tracer gas was introduced at 1 bar and monitored for 60 minutes. No pressure loss was recorded and no gas was detected.

4. 4
   Tracer gas test at 3 bar

   Testing was repeated at 3 bar, and tracer gas was detected in the corridor under the stairs — confirming an active leak, though the gas had migrated away from the actual source.

5. 5
   Endoscope camera inspection

   An endoscope camera was used beneath the floorboards to trace the leak. The source was identified as a faulty push-fit fitting beneath the tiled kitchen floor.

6. 6
   Tiles and boards lifted, fitting replaced

   With the owner's agreement, two tiles and the wooden floorboards were removed to access the fitting. The faulty push-fit fitting was found and replaced.

Result & Outcome

The leak was traced to a faulty push-fit fitting beneath the tiled kitchen floor. Although the thermal anomaly and the tracer gas detection pointed in slightly different directions — the gas surfaced under the stairs corridor rather than in the kitchen — the combination of methods used across this internal leak detection job allowed the engineer to pinpoint the exact fitting responsible for the pressure loss.

With the owner's agreement, two tiles and the wooden floorboards above the fitting were removed. The faulty push-fit fitting was confirmed and replaced on the same visit, resolving the source of the heating system pressure loss.

The engineer has recommended leaving the floor open to allow it to dry thoroughly before reinstatement, and setting the boiler to a low temperature during the drying period. This ensures the repair is not compromised by residual moisture trapped beneath the floor once it is sealed back up.