BoilerFaultCodesTechnical description
No water flow is detected for 60 secs and the temperature is less than 40ºC.
What causes this fault?
This fault occurs when the boiler's internal sensors do not detect any water movement after the pump has started. The most common cause is a seized or failing circulation pump that is no longer able to push water through the heat exchanger, but it can also be triggered by severe air locks or a total blockage in the heating circuit.
This fault is more frequent in autumn when the heating is turned back on after a long summer break, as pumps often seize up during periods of inactivity.
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.
Find a Gas Safe engineer
Search the official register →