Boiler frequently loses pressure and needs topping up every few days
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Do not repeatedly over-pressurise the system above 2.0 bar. This can cause further leaks.
User checks:
- Inspect for leaks: Check all radiators, valves, and visible pipework for damp patches or staining.
- Check external PRV discharge: Look at the copper pipe outside; if it drips when the boiler heats up, the pressure relief valve may be passing.
- Top up correctly: Use the filling loop to raise pressure to 1.0–1.2 bar when cold, then close both valves fully.
If pressure continues to drop, a heating engineer should test and recharge or replace the expansion vessel, replace the pressure relief valve, and locate any hidden leaks.
Repair Difficulty
Required Part
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