Keston Chronic Pressure Loss

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

Hidden leak in heating circuit, Faulty expansion vessel, Dripping pressure relief valve, Micro-leaks at radiator valves

How to Fix / Troubleshooting

Safety: Do not continually top up the system; this introduces fresh oxygen and accelerates corrosion.

User actions:

Visually inspect radiators, valves, and visible pipework for signs of leaks or staining.
Check the pressure relief valve discharge pipe outside for drips when the boiler is running.
Record pressure readings when cold and when hot to share with the engineer.

Engineer actions:

Test the expansion vessel pre-charge and recharge or replace if the diaphragm has failed.
Inspect the pressure relief valve for debris and replace if it continues to weep.
Use leak detection methods (dye, pressure test) to locate hidden leaks in the system.
Repair leaks and flush/chemically treat the system to prevent corrosion.

Repair Difficulty

Medium 3/5

Required Part

Expansion Vessel

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