BoilerFaultCodesWhat the manual says
Manufacturer manualFlue NTC Fault
From this model's manual
Verified against the Potterton/Potterton Promax He Store 4159176 installation & service manual.
What causes this fault?
This fault occurs when the sensor responsible for monitoring the temperature of the exhaust gases sends an incorrect or missing signal to the boiler's control board. The most common reason is that the sensor has physically failed due to age, but it can also be caused by loose wiring connections or the boiler running too hot.
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 21 fault codes on the Promax HE Store
Seeing a different code? Every code this model can display, in one place.