BoilerFaultCodesTechnical description
The difference between the boiler water temperature and the set DHW temperature is adjustable from 10 to 50K
What causes this fault?
This fault happens when the boiler cannot maintain the correct temperature gap between the hot water being heated and the burner's settings. It is often caused by a buildup of limescale or debris inside the plate heat exchanger, which prevents heat from transferring efficiently into your taps. Alternatively, a faulty sensor inside the unit might be providing inaccurate readings, causing the system to struggle with temperature regulation.
This issue is often more noticeable in winter when the incoming mains water is much colder, forcing the boiler to work harder to reach the target temperature.
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.