BoilerFaultCodesTechnical description
Return sensor temperature rise incorrect. The time taken for the return temperature to rise is too great.
What causes this fault?
This fault occurs when the boiler detects that the water returning to the unit isn't heating up as quickly as it should while the burner is active. The most common reasons are a blockage in the system or a failing pump that isn't moving the hot water away from the boiler fast enough. Sometimes, it can simply be a faulty sensor that is no longer reading temperatures accurately.
This issue is more common in autumn when heating systems are first turned on after a long summer break, often due to pump seizing or sludge build-up.
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.