Water heater frequently loses pressure and needs refilling.

Safety: Do not repeatedly overfill; high pressure can cause damage.

• Visual leak check: Inspect all visible radiators, valves, and joints for dampness or staining.
• Safety valve outlet: Check the discharge pipe from the safety valve for signs of water. If wet, the valve may be opening due to overpressure.
• Expansion vessel: A technician should check and recharge the expansion vessel pre‑charge pressure and replace it if the diaphragm has failed.
• Heat exchanger leak: If no external leaks are found, the primary heat exchanger may be leaking into the DHW side and requires professional diagnosis.