Glow Worm Fault Codes

Comprehensive reference table of all Glow Worm boiler error codes. Click any code for detailed troubleshooting steps.

Pro Tip

Check your boiler's digital display panel (usually behind a drop-down cover) to find the current active fault code.

Error CodeDescription
F.22Safety switch-off: Low water pressure in the boiler.
F.28Fault: Ignition unsuccessful when starting up.
F.29Fault: Flame loss during operation; possible condensate blockage.
F.75Fault: Pressure sensor; no pressure jump detected upon pump start.
F.32Fan frost protection active: Fan speed outside tolerance values.
F.20Safety switch-off: Overheating temperature reached.
F.23Safety switch-off: Temperature difference too great between NTC1/NTC2.
F.27Safety switch-off: Fault in flame detection (false flame).
F.61Fault: Gas valve control system; short circuit or defective electronics.
F.83Fault: EEPROM defective electronics or fault with burner temperature sensor.
F.00Fault: Flow temperature sensor disconnected or defective.
F.01Fault: Return temperature sensor disconnected or defective.
F.10Short circuit: Flow temperature sensor.
F.11Short circuit: Return temperature sensor.
F.24Safety switch-off: Temperature rises too fast.
F.25Safety switch-off: Flue gas temperature too high.
F.33Air pressure switch fault: Pressure monitor has not switched.
F.64Fault: Electronics/sensor/analogue-to-digital converter.
F.71Fault: Flow/return temperature sensor.
F.72Fault: Deviation in the water pressure sensor/return temperature sensor.
F.73Water pressure sensor not connected or has short-circuited.
F.76 / F.78The safety cut-out in the primary heat exchanger is defective.

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