Troubleshooting
Pressure Relief Valve Discharging Water
The relief valve is doing its job — but something upstream is wrong.
If you notice water dripping or running from the small pipe that exits your home's exterior wall near the boiler, the pressure relief valve (PRV) is discharging. This is a safety device releasing excess pressure — so while the valve is working correctly, the underlying cause (too-high pressure or a failed expansion vessel) needs fixing.
Diagnosis involves the sealed system, so book a technician.
Common causes
- System pressure too high
- Failed or waterlogged expansion vessel
- Filling loop left open
- Failed PRV that needs replacing
This is not a DIY repair
Combi boilers are gas-fired appliances regulated under the BC Safety Standards Act. Opening the unit, touching the gas valve, or working on the flue without a valid BC gas-fitter licence is both unsafe and illegal. Diagnosing the fault is helpful — fixing it should always be left to a certified technician.
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