Attack 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

Leaking Attack expansion vessel diaphragm, Small leak in heating pipework or radiators, Dripping safety relief valve, Micro‑leaks inside boiler hydraulic block

How to Fix / Troubleshooting

Safety: Do not overfill above the recommended pressure. Repeated topping up introduces oxygen and can cause corrosion.

Steps:

Check for visible leaks: Inspect all radiators, valves, and the boiler underside for damp patches or staining.
Monitor safety valve outlet: Place a small container under the discharge pipe (if safe) to see if water is being released when the system heats.
Expansion vessel test: If pressure rises sharply when hot and drops to zero when cold, the expansion vessel may be flat. A professional can check and recharge or replace it.

Repair Difficulty

Medium 3/5

Required Part

Expansion Vessel

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