BoilerFaultCodesWhat the manual says
Manufacturer manualReturn thermistor error
Shared across the Powermax HE range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
What causes this fault?
This fault occurs when the internal computer loses communication with the sensor that monitors water temperature coming back from your radiators. The most common reason is that the sensor has physically failed or developed an electrical fault, though it can also be caused by loose or damaged wiring connecting the sensor 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.
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Related fault codes
All 59 fault codes on the Powermax HE
Seeing a different code? Every code this model can display, in one place.