BoilerFaultCodesWhat the manual says
Manufacturer manualThermistor resistance value incorrect (9.7-10.3 kΩ at 25°C) or lack of continuity between the PCB and the thermistor.
What causes this fault?
This fault occurs when the sensor responsible for measuring the temperature of the water returning to the boiler begins to provide inaccurate readings or fails entirely. The most common reason is the internal electrical component within the sensor wearing out over time, though loose wiring or moisture on the connections can also disrupt the signal sent to the main control board.
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.
Avoid the next call-out bill
A cover plan would handle faults like Return Thermistor Fault: no call-out fees, no surprise bills.
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