Boiler frequently loses pressure and needs topping up every few days

Safety: Do not repeatedly operate the filling loop to compensate for leaks; this introduces fresh oxygen and can damage the system.

• Inspect PRV discharge: Check the copper safety discharge pipe outside. If it drips when the boiler runs, the PRV may be passing due to overpressure or debris.
• Look for visible leaks: Examine all radiators, valves, and accessible pipework for damp patches or staining.
• Record pressure pattern: Note whether pressure rises excessively when hot and drops when cold—this suggests an expansion vessel issue.
• Engineer tasks:
  • Test and recharge the Main expansion vessel; replace if the diaphragm has failed.
  • Replace a faulty PRV that does not reseal.
  • Use leak detection methods (dye, pressure test) to locate hidden leaks.