Boiler Losing Pressure, February 2017


Leak Detection was carried out to a detached property in Belfast, served by a Gas System boiler sited in a purpose built cupboard located in the utility room on ground floor of the property.

This boiler provides heat to 12 radiators and an indirect heating coil within hot water cylinder.   The cylinder is located in a purpose built cupboard on the 1st floor, this provides hot water to all outlets.

A cold water storage facility is sited in the roof space of the property and supplies water to basin, bath and WC.
Our customer had noticed that gas boiler was needing to be refilled with water on a regular basis and on more than one occasion the boiler had defaulted due to insufficient water within the system.

A call was made to service engineer and a diagnostic test had highlighted that a new pressure relief valve needed to be fitted.

On completion of this work system continued to loose water content and leak detection was advised by service engineer.

A survey was carried out, terms and conditions were agreed and return date agreed.

Pre Test Checks

No water could be held within the heating system long enough to test boiler.
The system was made safe electrically and isolated from gas supply.
All residue water content was removed from the system and safety and pressure relief valves removed from the system for duration of testing procedures.

Air Testing

Compressed air was pulsed through the system in order to remove any sludge, leak sealer and remaining water content.
Air test was placed on the system. Pressure was set at 3 bar and over a 7 minute period the pressure was at 0 bar.
The pressure was repeatedly injected to the system for next phase leak detection.

Acoustic Sounding

Acoustic listening equipment was used within ground floor.
Areas of concern were noted in hallway and ground floor Cloak room WC.

Area Of Concern – Acoustic Testing
Soundings were recorded in this area.

Tracer Gas Testing

All compressed air was removed from the system and tracer gas injected to the system. Readings were immediately recorded in the hallway.
This was in close proximity to the radiator in this location.

Tracer Gas Readings- Hallway

Due to the high readings in this area it was decided to remove a tile where the pipe supplied the radiator.

Tile Removal – Excavation

Pipe work was uncovered and water damage was recorded within sub floor of property.
Pipe work was followed and revealed a defect within heating system at branch situated under floor.

Further Testing

Following the phase of leak detection further defects were located.
A separate excavation was carried out in hallway and uncovered a secondary defect on underground pipework.
This location was exposed and as per previous findings pipework was capped at this location and the system retested.


Following testing procedure and repairs being carried out on 2 under ground fittings the system was retested.
No pressure drops were recorded at this time.
The system was purged of all testing procedures, valves reinstated where necessary and prepared for the reintroduction of water.

System Recommissioned

The system was refilled and boiler turned on. Pressure was set and a further testing period was observed over a 20 hour period. No pressure drop recorded.


All excavated areas were reinstated in preparation for tiling.


Following leak detection and subsequent repairs it is recommended that the pressure in the system is observed over the next week and any discrepancies reported back to Leak Locator. It is recommended that a safety check be carried out on the gas boiler and a certificate issued.

Please Note

Machinery and equipment is calibrated and tested prior to each visit and accurate at time of testing.
Please note, where pipework is ducted a variance in accuracy maybe recorded. In the unlikely event that there is more than one breach of pipework, only one area of concern can be addressed during this phase of works and this could result in a repeat of the testing procedures.