BoilerFaultCodesTechnical description
PRV Assembly
What causes this fault?
This fault occurs when the boiler's internal safety system detects that the pressure relief valve is no longer functioning correctly or has been triggered. The most common cause is a buildup of excessive pressure within the system, often due to a depleted expansion vessel or a leak in the valve assembly itself. Because this valve is a critical safety component designed to prevent the boiler from over-pressurising, the unit will shut down to prevent damage.
This issue often surfaces in autumn or winter when the heating is first turned on after summer, as the sudden heat causes water expansion that older expansion vessels and relief valves can no longer manage.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.