Glow-Worm Combi Boiler Error Codes
Glow-Worm Combi Boiler Error Codes

Glow-Worm Combi Boiler Error Codes

Glow-Worm Combi Boiler Error Codes An error code will flash on the display panel of your boiler. These codes are designed to help users to resolve general faults and they appear when something has gone wrong with your boiler.

Glow Worm error codes are used to diagnose problems and faults within your boiler system. Here we provide a comprehensive list of error codes for Glow Worm boilers, together with an explanation as to what each means and how to fix the problem.

Glow-worm Boiler Error Code Solutions

Boiler Model Fault Codes Cause of Problem
BetacomRed LED OnLockout – low water pressure (increase pressure to 1.5bar) and reset boiler
BetacomRed LED flashingOverheat – check both overheat stats
BetacomYellow LED flashingTurn domestic hot water (DHW) control knob into temperature range and turn central heating (CH) temperature control knob into power (reset position)
BetacomYellow LED onFlame present on the burner
BetacomGreen LED onGreen LED on
BetacomGreen LED offNo power to boiler – Check for 230volts into the appliance, check the fuse on printed circuit board (PCB)
Betacom4 / Ultracom3 cxi / sxi / 35F00 / F10 / F71Flow heating temperature sensor fault
Betacom4 / Ultracom3 cxi / sxi / 35F01 / F11Return heating temperature sensor fault
Betacom4 / Ultracom3 cxi / sxi / 35F20Overheating fault
Betacom4 / Ultracom3 cxi / sxi / hxi / 35 / Flexicom cx / hx / sxF9 / F22Low water pressure (or ignition temperature rise too slow)
Betacom4 / Ultracom3 cxi / sxi / 35F26 / F77Fault in gas valve
Betacom4 / Ultracom3 cxi / sxi / 35 / CI / hxi / Xtramax HEF27 / F16Flame detection fault
All BoilersF28 / F1/ F4Ignition fault (flame detection)
Betacom4 / Ultracom3 cxi / sxi / 35F29Loss of flame during operation
Betacom4 / Ultracom3 cxi / sxi / 35F32Incorrect air pressure
Betacom4 / Ultracom3 cxi / sxi / 35F49EBUS voltage fault
Betacom4 / Ultracom3 cxi / sxi / 35F61 / F62 / F63 / F64 / F65 / F67Fault in the main board
Betacom4 / Ultracom3 cxi / sxi / 35F68Fluctuation of flame signal
Betacom4 / Ultracom3 cxi / sxi / 35F70User interface incompatible with the main board
Betacom4 / Ultracom3 cxi / sxi / 35F72 / F84Permanent temperature difference between flow and return heating sensors
Betacom4 / Ultracom3 cxi / sxi / 35F73 / F74Heating circuit pressure sensor fault
Betacom4 / Ultracom3 cxi / sxi / 35F76Thermal fuse fault
Betacom4 / Ultracom3 cxi / sxi / 35F83Thermal fuse fault
Betacom4 / Ultracom3 cxi / sxi / 35F85Flow and Return heating sensor fault
Betacom4/ Ultracom3 cxi / sxi / 35F86Underfloor heating contact fault
All BoilersERR / F12 / F18User interface fault
Betacom cTemperature 30 flashingFault on central heating (CH) thermistor
Betacom cTemperature 40 flashingFault on DHW thermistor
Betacom cTemperature 50 flashingFault on outside sensor
Betacom cTemperature 60 flashingLow system pressure
Betacom cTemperature 70 flashingFault on APS
Betacom cTemperature 80 flashingOverheat open circuit
Betacom cTemperature 90 flashingFlame or gas failure
Compact e / sNo DHWCheck dhw microswitch / Check external controls, Please test for 230V on switch live contact
Compact e / sNo C/HCheck dhw microswitch if dhw demand led is lit / Check external controls, Please test for 230V on switch live contact
Compact e / sNo C/H but boiler is firingCheck divertor motor and cartridge / Check external controls, Please test for 230V on switch live contact
Compact e / sBoiler locks out within 10 secondsCheck pump proving switch, air pressure switch and overheat state / Check pump proving switch, air pressure switch and overheat stat
Compact e / sPoor burner pressureCheck burner pressure/ignition adjustment pots on PCB
Ci Range (plus) / Si rangeF2Fan/APS
All BoilersF5Overheat Fault
All BoilersF6Central heating flow thermistor
All BoilersF7Domestic hot water thermistor
All BoilersF8Tank thermistor fault
sxi / si / ci (plus) range / Xtramax HEF9Water pressure sensor fault (please contact GW technical department for further information)
All boilersF10Central return flow thermistor
All boilersF11Main board connection fault
Ci (plus) / cxi / hxi / si / sxi rangeF12Connection fault between main printed circuit board (PCB) and display PCB
Ci (plus) / cxi / hxi / si / sxi rangeF13Main pcb connection fault
Ci (plus) / cxi / hxi / si / sxi rangeF14Central heating flow temperature > 95 degrees
Ci (plus) / cxi / si / sxi rangeF15Gas valve stepper motor fault
Ci (plus) / cxi / hxi / si / sxi range / Xtramax HEF17Power supply is less than 170v
Ci (plus) / cxi / hxi / si / sxi range / Xtramax HEF19Central heating thermistor unplugged
Ci (plus) / cxi / hxi / si / sxi range / Xtramax HEF20Software incompatibility
cxi / hxi / sxi range / Flexicom cxF24Central heating return temperature > 90 degrees
cxi / hxi / sxi / Xtrafast 96/120 / Xtrafast 96/120E1F25 / F26 / F11Poor circulation
ci rangeF3Air fault
cxi / sxi / hxi range/ Xtramax HEF2 / F3Fan
cxi / sxi range / Flexicom cx / hx / sx / hxi / Ultracom cxi / cx / hxi / sxi / Ultrapower sxiF3Fan unable to reach ignition speed
Flexicom cx / hx / sx / hxi / Ultracom cxi / cx / hxi / sxiF9Water pressure sensor fault, blocked flow filter or pump fault
Flexicom cx / hx / sxF11Flow and or return thermistor fault
Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi / Xtramax HEF13PCB memory or sensing fault
Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi / Xtramax HEF14Gas valve control defective
Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi / Xtramax HEF15E-bus voltage failure
All boilersF25 / F23Circulation fault
Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxiF43Generic error
Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxiF70Software incompatible
Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxiF73Unable to see pump activate
Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxiF77Condensate pump error (optional)
hxi rangeF9Earlier models only (please contact GW technical department for further information)
Ultracom? 35 StoreF02 / F12Hot water temperature sensor fault
Ultracom? 35 StoreF03 / F13 / F79Storage tank temperature sensor fault
Ultracom? 35 StoreF81Overheating of hot water circuit
All UltracomNo display or Erloose connection X51
Xtramax HE RangeF24Cental heating return temperature > 90 degrees
Xtramax HE RangeF25Maximum temperature rise slope
Xtramax HE RangeF26Maximum delta temperature
Xtrafast 96/120 RangeF00No-fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF00No-fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF02Airflow fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF05Overheating
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF06Central heating thermistor/wiring fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF08Storage vessel thermistor/wiring fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF09System pressure sensor fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF10Fan fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF13Main printed circuit board (PCB) fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF14Central heating flow temperature > 97 degrees
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF15Gas mechanism fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF20Communication fault

Glow-worm Energy boiler range error codes

Fault CodeCause of Problem
F.00Flow temperature sensor
F.10Flow temperature sensor short circuit
F.12 and F.91Cylinder temperature sensor short circuit
F.13Domestic hot water cylinder temperature sensor short circuit
F.20Safety switch-off – overheating temperature reached
F.22Safety switch-off – low water pressure in the boiler
F.23Safety switch-off – temperature difference too great (NTC1/NTC2)
F.24Safety switch-off – temperature rise too fast
F.25Safety switch-off – flue gas temperature too high
F.27Safety switch-off – fault in flame detection
F.28Ignition unsuccessful when starting up
F.29Flame loss
F.32Fan frost protection function active – fan speed outside the tolerance values
F.33Fan frost protection function active – air pressure switch fault
FA9eBUS fault – voltage too low
F.61Gas valve control system fault
F.82Gas valve switch-off control fault
F.83EEPROM fault – electronics defective
F.64Electronics/sensor/analogue-to-digital converter fault
F.85Electronics temperature too high
F.67Value sent back by ASIC is incorrect (flame signal)
F.88Unstable flame (analogue input), underfloor heating contact or gas valve fault
F.70Invalid product code (DSN)
F.71Flow/return temperature sensor
F.72Deviation in the water pressure sensor/return temperature sensor
F.73Water pressure sensor not connected or has short-circuited
F.74Electrical problem in the water pressure sensor
F.75Pressure sensor fault
F.78The safety cut-out in the primary heat exchanger is defective
F.77Fault: Condensate or smoke
F.78Interruption to domestic hot water (DHW) outlet sensor at external controller
F.83Burner temperature sensor fault
F.84Flow/return temperature sensor fault
F.85Temperature sensor fault
F.87Electrodes fault
F.89Pump fault
ConnectionNo communication between the printed circuit board (PCB) and the user interface

Glow-worm Error Codes F1, F4, F28 or F29

If you are seeing the error codes F1, F4 F28, or F29 on your boiler there’s an issue with your condensate pipe. This error appears when your pipe is frozen, which can happen during the cold months as it runs outdoors. You can fix this issue yourself if you feel confident enough, otherwise call an engineer, by thawing out the pipe which you can find out how to do with our handy guide to thawing a condensate pipe.

Leave a Reply

Your email address will not be published. Required fields are marked *