BoilerFaultCodesTechnical description
Boiler shut down due to air passing through the pump or system not correctly vented (monitors temperature rise across the heat exchanger).
What causes this fault?
This fault occurs when air enters the internal pipework or the water stops moving quickly enough, causing the heat exchanger to reach high temperatures too fast. The most common reason is trapped air bubbles passing through the pump or a pump that is beginning to fail and can no longer push water through the boiler effectively.
This fault is frequently seen in autumn when heating systems are turned back on after summer, as air often settles in the radiators and pipework during the period of disuse.
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.