Boiler frequently loses pressure and needs topping up

Safety: Do not repeatedly overfill the system; this can damage components.

• Inspect for visible leaks: Check all radiators, valves, and accessible pipes for damp patches or staining.
• Check PRV discharge: Look at the end of the pressure relief valve discharge pipe outside. If it's wet or dripping, the valve is passing and may need replacement.
• Expansion vessel test (basic): If pressure rises very high when hot and drops to zero when cold, the expansion vessel is likely failed. This requires an engineer to recharge or replace.
• Monitor pressure: After topping up to 1.2 bar, note how quickly pressure drops. Rapid loss suggests a significant leak that must be located and repaired professionally.