Hot Water System Leak Detection in West Byfleet

Symptoms

The boiler at a property in KT14 had been running continuously, refusing to settle — a persistent sign that something was wrong in the system. The hot water circuit was suspected as the source, with the boiler prioritising hot water over heating whenever it was switched on.

This behaviour pointed clearly to a pressure loss on the hot pipe, consistent with an active leak somewhere beneath the floor.

Floor coverings in the affected area had already begun to peel away, a visible consequence of a hot pipe leaking beneath the surface over time. The scale of the damage suggested the leak had been active long enough for sustained heat and moisture to degrade the floor from below.

A hot water leak detection survey was the appropriate next step to locate the source without unnecessary destruction.

The combination of a boiler that wouldn't hold pressure and a floor visibly lifting gave a clear picture: there was a buried leak on the hot pipework, and it needed to be found and repaired before the damage worsened.

Methods Used

The investigation began with a pressure test on the hot pipe, which confirmed a leak was present. From there, thermal imaging and damp metre readings were taken across the floor to map the spread of heat and moisture.

Both indicated a large affected area, with significant heat spread and high damp readings beneath the floor surface. Tracer gas was then injected into the hot pipe, and a gas analyser was used to pinpoint where the gas was escaping — it gave a clear reading directly beneath the basin in the downstairs toilet.

With the leak area identified, the floor was opened with the customer's permission. This is the standard progression in hot water leak detection: non-invasive methods narrow the search area, then targeted excavation confirms the exact fault.

Two separate defects were ultimately found — a point where two copper pipes had been crossing and bearing on each other, and a pinhole further along the same run — both located by following the gas indication through the opened floor.

Investigation Process

1. 1
   Boiler behaviour observed

   On arrival, the engineer asked the customer to turn on the boiler. It was immediately observed prioritising hot water over heating, indicating a pressure issue on the hot pipe.

2. 2
   Pressure test on hot pipe

   A pressure test was carried out on the hot pipe. The result confirmed a leak was present on this circuit.

3. 3
   Thermal imaging and damp metre survey

   Thermal imaging and damp metres were deployed across the floor. Both indicated a large spread of heat and significant moisture beneath the surface.

4. 4
   Tracer gas injection and gas analysis

   Tracer gas was injected into the hot pipe and a gas analyser was used to trace the escape point. A positive reading was obtained beneath the basin in the downstairs toilet.

5. 5
   Floor opened and first leak located

   With the customer's permission, the floor was excavated in the indicated area. Two copper pipes were found crossing and sitting on top of each other; this contact point was the first defect. The pipes were cut out and repaired.

6. 6
   Re-pressure test reveals second leak

   After the first repair, the system was re-pressure tested but failed. The gas analyser indicated a further leak further along the run.

7. 7
   Second leak located and repaired

   Further excavation uncovered a pinhole in the pipework. This was repaired using copper pipe and fittings.

8. 8
   Final pressure test and system check

   Both repairs were completed and the system was pressure tested with no further failures. The boiler was confirmed to be operating correctly with the heating now functioning.

Result & Outcome

Two separate leaks were found and repaired in the hot pipework beneath the floor at the property in KT14. The first was at a point where two copper pipes had been laid crossing over each other, causing contact stress that eventually led to failure. The second was a pinhole in the pipework a short distance further along the same run. Both defects were excavated, cut out, and repaired with copper pipe and fittings. A final pressure test confirmed no further leaks remained, and the boiler returned to normal operation with the heating functioning correctly.

This is a good illustration of how hot water leak detection sometimes reveals more than one fault: the initial gas indication led to the primary repair, but re-pressure testing after that repair exposed a secondary defect that would otherwise have remained hidden. Following the gas trace further down the pipe run was what allowed both issues to be resolved in a single visit.

The floor has sustained significant damage — coverings have peeled away over a wide area as a result of prolonged heat and moisture from the leaking pipe. The engineer has noted that the area will need time to dry out before concrete reinstatement, and that the exposed pipes should be properly protected. There is also a recommendation to reroute some of the pipework to eliminate the crossover configuration, which is the underlying cause of the first failure and could cause problems again if left as-is.