BoilerFaultCodesTechnical description
Hot water thermistor fault (Open or Short circuit)
What causes this fault?
This fault occurs when the boiler's control board fails to detect a flame after several attempts to light the burner. The most common reasons include a lack of gas supply to the unit, a worn-out ignition electrode that can no longer create a spark, or debris blocking the burner.
This fault is slightly more common in winter, as extreme cold can cause external gas regulators to freeze or gas pressure to drop across the local network.
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.
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