Boiler frequently loses pressure and needs topping up every few days

Safety: Repeated topping up introduces fresh oxygen and can damage the system. Do not ignore ongoing pressure loss.

• Check visible leaks: Inspect all radiators, valves, and visible pipes for damp patches or staining.
• PRV discharge: Look at the pressure relief valve discharge pipe outside. If it is dripping, the PRV may be passing due to overpressure or debris.
• Expansion vessel test (basic): With the system cold and depressurised, gently press the Schrader valve on the expansion vessel. If water comes out, the diaphragm has failed and the vessel must be replaced.
• Professional leak detection: If no obvious leaks are found, a heating engineer can pressure-test the system and use leak detection methods to locate hidden faults.