BoilerFaultCodesWhat the manual says
Manufacturer manualFlue thermistor error
What causes this fault?
This fault occurs when the boiler's internal computer receives an incorrect or missing signal from the sensor that monitors the heat of the exhaust gases. It is usually caused by the sensor itself failing due to age, or a fault in the wiring that connects the sensor to the main control panel. Because the boiler cannot confirm that the exhaust fumes are at a safe temperature, it shuts down immediately to prevent heat damage.
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 E33: no call-out fees, no surprise bills.
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All 59 fault codes on the Powermax HE
Seeing a different code? Every code this model can display, in one place.