BoilerFaultCodesTechnical description
Domestic hot water pump/loading fault
What causes this fault?
This fault occurs when the boiler detects that water is not being heated quickly enough for your taps, often because the internal pump has seized or failed. It can also be triggered by a buildup of limescale or debris in the heat exchanger, which restricts water flow and prevents the system from transferring heat effectively. Essentially, the boiler is shutting down because it cannot move the hot water out of the unit fast enough to avoid overheating.
This issue is more frequently reported in winter when the incoming cold water temperature drops, forcing the boiler to work harder and highlighting any existing blockages or pump weaknesses.
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.