Central Heating Leak Detection in Camberwell

Symptoms

The property in SE22, a two-story terraced residence, had been experiencing a gradual loss of pressure in the central heating system. The customer reported losing approximately 1 bar every 12 hours — a slow but consistent drop indicating a leak somewhere within the system.

Visible water damage was present in the bathroom and on adjacent walls, and an area of uplifted tiles in the bathroom pointed toward the likely source.

A complicating factor was that a leak in the same area had previously been identified and repaired in December, with excavation already carried out beneath the bathroom floor at that time. The recurrence of pressure loss after that earlier repair raised the question of whether the previous fix had held or whether a new fault had developed nearby.

For a central heating leak detection job of this nature — where a prior repair exists and pressure loss is gradual rather than sudden — standard visual inspection is insufficient. The slow rate of loss meant the fault could be subtle, and the existing excavation site made it difficult to isolate whether the problem was at the original repair point or elsewhere in the system.

Methods Used

Given the gradual pressure loss and the presence of a previously repaired area, the investigation was structured to systematically eliminate possibilities before committing to further excavation. Moisture meter readings were taken first to assess the extent of damp in the bathroom floor and surrounding walls.

Thermal imaging was then used to trace the route of the heating pipework through the structure, though this did not reveal any temperature anomalies indicative of a leak.

With thermal imaging returning no findings, the boiler was isolated and the system drained to allow tracer gas testing. This is the appropriate approach for central heating leak detection where the leak rate is too low to be detected by pressure testing alone under normal conditions.

Gas was introduced at multiple pressures, and after a pressure drop of approximately 0.1 bar was observed, tracer gas was detected concentrating around the original excavation site in the bathroom floor. This gave sufficient confidence to excavate the area and inspect the pipework directly.

Investigation Process

1. 1
   Initial observations and moisture readings

   On arrival, visible water damage was noted in the bathroom and on adjacent walls, with uplifted tiles indicating disturbance to the floor. Moisture meter readings confirmed elevated damp levels in and around the previously excavated area.

2. 2
   Thermal imaging of heating pipework

   Thermal imaging was used to trace the heating pipework through the bathroom and surrounding structure. No anomalies were identified that could indicate the location of the leak.

3. 3
   Boiler isolated and system drained

   With thermal imaging returning no findings, the boiler was isolated and the central heating system was fully drained in preparation for tracer gas testing.

4. 4
   Tracer gas testing at multiple pressures

   Tracer gas was introduced into the system and tests were conducted at multiple pressures. A pressure drop of approximately 0.1 bar was observed, and tracer gas was detected concentrating at the original excavation site in the bathroom floor.

5. 5
   Excavation and fault identification

   The bathroom floor was excavated at the area indicated by the tracer gas. This revealed a leaking 15mm fitting at the location of the previous repair.

6. 6
   Repair carried out

   The affected section was drained and repaired using 15mm copper pipe and two 15mm soldered straight couplers, replacing the faulty fitting.

7. 7
   System re-tested and boiler recommissioned

   Following the repair, the system was re-tested and no further leaks were identified. The boiler was re-pressurised and tested for both heating and hot water functionality, confirming the system was operating correctly.

Result & Outcome

The leak was located at the original excavation site in the bathroom floor, where a 15mm fitting from the December repair had developed a fault. Tracer gas detection provided a precise fix on the location before any additional excavation was carried out, avoiding unnecessary disruption to the surrounding floor area.

The repair involved replacing the faulty fitting with 15mm copper pipe and two 15mm soldered straight couplers. After the repair, the system was re-tested at pressure and no further leaks were found. The boiler was re-pressurised and confirmed to be functioning correctly for both heating and hot water.

For a central heating leak detection case involving a slow pressure loss after a previous repair, this outcome confirms the integrity of the system going forward. The customer was advised to allow the affected area to dry thoroughly before re-tiling the excavated section of the bathroom floor.