Boiler frequently loses pressure and needs regular topping up.
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: Do not repeatedly overfill the system above the recommended pressure; this can cause further leaks.
User checks:
- Inspect visible pipework, radiators and valves for signs of dampness or staining.
- Check the condensate outlet; continuous dripping when the boiler is off may indicate an internal leak.
Engineer checks:
- Test the expansion vessel on the EHC boiler; recharge or replace if the diaphragm has failed.
- Check the pressure relief valve for passing; replace if it drips even at normal pressure.
- Perform a pressure test on the heating circuit to locate hidden leaks.
Once the underlying leak or vessel fault is resolved, the system should maintain stable pressure without frequent topping up.
Repair Difficulty
Required Part
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