Glow Worm Repair Specialist

Repair Network has the experienced gas-safe engineer you need for repairs and service on your Glow Worm boiler.
Same or next day service, nationwide coverage, fixed-cost boiler repairs and a one-year guarantee.

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Glow Worm Boilers

Glow Worm boilers are available as combi, system and regular models.
For more than 80 years, Glow Worm has been leading the heating industry in the UK. It started in 1934 in Derbyshire when the first boiler was produced. During the decades since, Glow Worm has been producing durable and long-lasting heating solutions.
Acquired by the Valliant brand in 2001, Glow Worm is now part of the second largest heating company in Europe. The brand is recognised as the leading manufacturer in high efficiency boilers since 2005.
Glow Worm offers warranties and guarantees for its boilers and their parts, depending on the model and package you choose.

Do you own any Glow Worm Boiler?

Require some form of repairs!

Book a certified technician with the tools and experience to repair all your Glow Worm Boiler!

03333449104

Available 9 AM to 7 PM

Same day or next day repair

Why Repair Network Nationwide?

When you have a broken boiler, you want a fast, reliable and efficient repair service that is also affordable. Repair Network promises a prompt boiler repair service, carried out by a local, qualified technician.
To limit the frustration and hassle of living without your boiler, we offer set appointment times to keep you from having to wait for a service call. We always strive to provide same or next day service.
Not only do we offer nationwide coverage, but all our local technicians are gas registered to ensure that your service is both high quality and safely carried out. We also guarantee to send a technician with experience working on your brand of boiler.
We always aim to fix your boiler, preventing you from having to replace it. Our repair, not replace policy comes with a one year guarantee.

What we Cover and What we Don’t

We are transparent with our pricing because our top goal is customer satisfaction.
All of our boiler repairs comes at a fixed cost and we won’t surprise you with hidden fees. The fixed cost includes labor and genuine brand approved parts.
If an engineer isn’t able to repair your Glow Worm boiler, they will offer a free, no-obligation quote for a replacement boiler, which includes installation.
Find your fault code for your Glow Worm boiler below:

What are the error codes Glow Worm Boilers and what do the mean?

Determine the model of your Glow Worm boilers and look to the ahead for the various error codes and what they mean.

Find your Error Code

Energy Boiler Range Fault Codes

Fault codesMeaning
F.00 Fault: Flow temperature sensor
F.01 Fault: Return temperature sensor
F.10 Short circuit: Flow temperature sensor
F.11 Short circuit: Return temperature sensor
F.12 and F.91 Short circuit: Cylinder temperature sensor
F.13 Short circuit: Domestic hot water cylinder temperature sensor
F.20 Safety switch-oft. Overheating temperature reached
F.22 Safety switch-oft. Low water pressure in the boiler
F.23 Safety switch-oft. Temperature difference too great (NTC1/NTC2)
F.24 Safety switch-oft. Temperature rise too fast
F.25 Safety switch-off. Flue gas temperature too high
F.27 Safety switch-off. Fault in flame detection
F.28 Fault: Ignition unsuccessful when starting up
F.29 Fault: Flame loss
F.32 Fan frost protection function active: Fan speed outside the tolerance values
F.33 Fan frost protection function active: Air pressure switch fault
FA9 eBUS fault: Voltage too low
F.61 Fault: Gas valve control system
F.82 Fault: Gas valve switch-off control
F.83 Fault: EEPROM
F.64 Fault: Electronics/sensor/analogue-to-digital converter
F.85 Fault: Electronics temperature too high
F.67 Value sent back by ASIC is incorrect (flame slgnal)
F.88 Fault: Unstable flame (analogue input)
F.70 Invalid product code (DSN)
F.71 Fault: Flow/return temperature sensor
F.72 Fault: Deviation in the water pressure sensor/return temperature sensor
F.73 Fault: Water pressure sensor not connected or has short-circuited
F.74 Fault: Electrical problem in the water pressure sensor
F.75 Fault: Pressure sensor
F.78 The safety cut-out in the primary heat exchanger is defective
F.77 Fault: Condensate or smoke
F.78 Interruption to DHW outlet sensor at external controller
F.83 Fault: Burner temperature sensor
F.84 Fault: Flow/return temperature sensor
F.85 Fault: Temperature sensor
F.88 Fault: Underfloor heating contact
F.87 Fault: Electrodes
F.88 Fault: Gas valve
F.89 Fault: Pump
Connection No communication between the PCB and the user interface

Betacom Range

CodesDescription
Red LED on Lockout - Low water pressure, Make sure pressure is above 1.5bar, reset boiler
Red LED flashing DHW temperature control knob in service position - Turn DHW control knob into temperature range
Red LED flashing Overheat - Check both overheat stats
Yellow LED flashing Error - Turn DHW control knob into temperature range and turn CH temperature control knob into power (reset position) and wait for minimum of 30 seconds before turning into either summer or temperature position
Yellow LED on Flame present on the burner
Green LED on Boiler ready for operation
Green LED off No power to boiler - Check for 230volts into the appliance, check fuse on pcb
Green LED flashing Boiler in stand-by - Reset position

Betacom a Range

CodesDescription
F00 Flow heating temperature sensor fault
F01 Return heating temperature sensor fault
F10 Flow heating temperature sensor fault
F11 Return heating temperature sensor fault
F20 Overheating fault
F22 Low water pressure
F23 Water circulation fault
F24 Water circulation fault
F26 Fault in gas valve
F27 Flame detection fault
F28 Ignition fault
F29 Loss of flame during operation
F32 Incorrect air pressure
F49 EBUS voltage fault
F61 Fault in the main board
F62 Fault in the main board
F63 Fault in the main board
F64 Fault in the main board
F65 Fault in the main board
F67 Fault in the main board
F68 Fluctuation of flame signal
F70 User interface incompatible with the main board
F71 Flow heating temperature sensor fault
F72 Permanent temperature difference between flow and return heating sensors
F73 Heating circuit pressure sensor fault
F74 Heating circuit pressure sensor fault
F76 Thermal fuse fault
F77 Fault in gas valve motor
F83 No water in the installation
F84 Permanent temperature difference between flow and return heating sensors
F85 Flow and Return heating sensor fault
F86 Underfloor heating contact fault
Err User interface fault

Betacom c Range

CodesDescription
F00 Flow heating temperature sensor fault
F01 Return heating temperature sensor fault
F10 Flow heating temperature sensor fault
F11 Return heating temperature sensor fault
F20 Overheating fault
F22 Low water pressure
F23 Water circulation fault
F24 Water circulation fault
F26 Fault in gas valve
F27 Flame detection fault
F28 Ignition fault
F29 Loss of flame during operation
F32 Incorrect air pressure
F49 EBUS voltage fault
F61 Fault in the main board
F62 Fault in the main board
F63 Fault in the main board
F64 Fault in the main board
F65 Fault in the main board
F67 Fault in the main board
F68 Fluctuation of flame signal
F70 User interface incompatible with the main board
F71 Flow heating temperature sensor fault
F72 Permanent temperature difference between flow and return heating sensors
F73 Heating circuit pressure sensor fault
F74 Heating circuit pressure sensor fault
F76 Thermal fuse fault
F77 Fault in gas valve motor
F83 No water in the installation
F84 Permanent temperature difference between flow and return heating sensors
F85 Flow and Return heating sensor fault
F86 Underfloor heating contact fault
Err User interface fault

CI Range

CodesDescription
F1 Ignition fault
F2 Fan/APS
F4 Ignition fault
F5 Overheat Fault
F6 Central heating flow thermistor
F7 Domestic hot water thermistor
F8 Tank thermistor (N/A For this appliance)
F9 Water pressure sensor fault (please contact GW technical department for further information
F10 Central return flow thermistor
F11 Main board connection fault
F12 Connection fault between main pcb and display pcb
F13 Main pcb connection fault
F14 Central heating flow temperature > 95 degrees
F15 Gas valve stepper motor fault
F16 Flame detection fault
F17 Power supply is less than 170v
F18 User interface fault
F19 Central heating thermistor unplugged
F20 Software incompatibility

CI Plus Range

CodesDescription
F1 Ignition fault
F2 Fan/APS
F3 Air fault
F4 Ignition fault
F5 Overheat Fault
F6 Central heating flow thermistor
F7 Domestic hot water thermistorhttps://www.repair-network.co.uk/wp-admin/post.php?post=1634&action=edit#
F8 Tank thermistor (N/A For this appliance)
F9 Water pressure sensor fault (please contact GW technical department for further information
F10 Central return flow thermistor
F11 Main board connection fault
F12 Connection fault between main pcb and display pcb
F13 Main pcb connection fault
F14 Central heating flow temperature > 95 degrees
F15 Gas valve stepper motor fault
F16 Flame detection fault
F17 Power supply is less than 170v
F18 User interface fault
F19 Central heating thermistor unplugged
F20 Software incompatibility

Cxi Range

CodesDescription
F1 Ignition fault
F2 Fan
F3 Fan unable to reach ignition speed
F4 Ignition fault
F5 Overheat Fault
F6 Central heating flow thermistor
F7 Domestic hot water thermistor
F8 Tank thermistor (N/A For this appliance)
F9 Water pressure sensor fault (please contact GW technical department for further information
F10 Central return flow thermistor
F11 Main board connection fault
F12 Connection fault between main pcb and display pcb
F13 Main pcb connection fault
F14 Central heating flow temperature > 95 degrees
F15 Gas valve stepper motor fault
F16 Flame detection fault
F17 Power supply is less than 170v
F18 User interface fault
F19 Central heating thermistor unplugged
F20 Software incompatibility
F24 Central heating return temperature > 90 degrees
F25 Poor circulation
F26 Poor circulation

Flexicom cx Range

CodesDescription
F1 Ignition fault
F3 Fan unable to reach ignition speed
F4 Ignition fault
F5 Overheat Fault
F6 Central heating flow thermistor
F7 Domestic hot water thermistor
F9 Water pressure sensor fault, blocked flow filter or pump fault
F10 Central return flow thermistor
F11 Flow and or return thermistor fault
F13 PCB memory or sensing fault
F14 Gas valve control defective
F15 E-bus voltage failure
F22 Low water pressure or ignition temperature rise too slow
F24 Central heating return temperature > 90 degrees
F25 Circulation fault
F43 Generic error
F70 Software incompatible
F73 Unable to see pump activate
F77 Condensate pump error (optional)

Flexicom hx Range

CodesDescription
F1 Ignition fault
F3 Fan unable to reach ignition speed
F4 Ignition fault
F5 Overheat Fault
F6 Central heating flow thermistor
F9 Low water pressure Sensor
F10 Central return flow thermistor
F11 Flow and or return thermistor fault
F13 PCB memory or sensing fault
F14 Gas valve control defective
F15 E-bus voltage failure
F22 Low water pressure or ignition temperature rise too slow
F25 Circulation fault
F43 Generic error
F70 Software incompatible
F73 Unable to see pump activate
F77 Condensate pump error (optional)

Flexicom sx Range

CodesDescription
F1 Ignition fault
F3 Fan unable to reach ignition speed
F4 Ignition fault
F5 Overheat Fault
F6 Central heating flow thermistor
F7 Domestic hot water thermistor
F9 Low water pressure Sensor
F10 Central return flow thermistor
F11 Flow and or return thermistor fault
F13 PCB memory or sensing fault
F14 Gas valve control defective
F15 E-bus voltage failure
F22 Low water pressure or ignition temperature rise too slow
F25 Circulation fault
F43 Generic error
F70 Software incompatible
F73 Unable to see pump activate
F77 Condensate pump error (optional)

hxi Range

CodesDescription
F1 Ignition fault
F2 Fan
F3 Fan unable to reach ignition speed
F4 Ignition fault
F5 Overheat Fault
F6 Central heating flow thermistor
F7 Domestic hot water thermistor
F8 Tank thermistor (N/A For this appliance)
F9 Earlier models only (please contact GW technical department for further information)
F10 Central return flow thermistor
F11 Main board connection fault
F12 Connection fault between main pcb and display pcb
F13 Main pcb connection fault
F14 Central heating flow temperature > 95 degrees
F16 Flame detection fault
F17 Power supply is less than 170v
F18 User interface fault
F19 Central heating thermistor unplugged
F20 Software incompatibility
F24 Cental heating return temperature > 90 degrees
F25 Poor circulation
F26 Poor circulation

SI Range

CodesDescription
F1 Ignition fault
F2 Fan/APS
F4 Ignition fault
F5 Overheat Fault
F6 Central heating flow thermistor
F7 Domestic hot water thermistor
F8 Tank thermistor (N/A For this appliance)
F9 Water pressure sensor fault (please contact GW technical department for further information)
F10 Central return flow thermistor
F11 Main board connection fault
F12 Connection fault between main pcb and display pcb
F13 Main pcb connection fault
F14 Central heating flow temperature > 95 degrees
F15 Gas valve stepper motor fault
F16 Flame detection fault
F17 Power supply is less than 170v
F18 User interface fault
F19 Central heating thermistor unplugged
F20 Software incompatibility

sxi Range

CodesDescription
F1 Ignition fault
F2 Fan
F3 Fan unable to reach ignition speed
F4 Ignition fault
F5 Overheat Fault
F6 Central heating flow thermistor
F7 Domestic hot water thermistor
F8 Tank thermistor (N/A For this appliance)
F9 Water pressure sensor fault (please contact GW technical department for further information)
F10 Central return flow thermistor
F11 Main board connection fault
F12 Connection fault between main pcb and display pcb
F13 Main pcb connection fault
F14 Central heating flow temperature > 95 degrees
F15 Gas valve stepper motor fault
F16 Flame detection fault
F17 Power supply is less than 170v
F18 User interface fault
F19 Central heating thermistor unplugged
F20 Software incompatibility
F24 Cental heating return temperature > 90 degrees
F25 Poor circulation
F26 Poor circulation

Ultracom₂ cxi Range and Ultracom₂ sxi Range

CodesDescription
F00 Flow heating temperature sensor fault
F01 Return heating temperature sensor fault
F10 Flow heating temperature sensor fault
F11 Return heating temperature sensor fault
F20 Overheating fault
F22 Low water pressure
F23 Water circulation fault
F24 Water circulation fault
F26 Fault in gas valve
F27 Flame detection fault
F28 Ignition fault
F29 Loss of flame during operation
F32 Incorrect air pressure
F49 EBUS voltage fault
F61 Fault in the main board
F62 Fault in the main board
F63 Fault in the main board
F64 Fault in the main board
F65 Fault in the main board
F67 Fault in the main board
F68 Fluctuation of flame signal
F70 User interface incompatible with the main board
F71 Flow heating temperature sensor fault
F72 Permanent temperature difference between flow and return heating sensors
F73 Heating circuit pressure sensor fault
F74 Heating circuit pressure sensor fault
F76 Thermal fuse fault
F77 Fault in gas valve motor
F83 No water in the installation
F84 Permanent temperature difference between flow and return heating sensors
F85 Flow and Return heating sensor fault
F86 Underfloor heating contact fault
Err User interface fault

Ultracom₂ 35 Store

CodesDescription
F00 Flow heating temperature sensor fault
F01 Return heating temperature sensor fault
F02 Hot water temperature sensor fault
F03 Storage tank temperature sensor fault
F10 Flow heating temperature sensor fault
F11 Return heating temperature sensor fault
F12 Hot water temperature sensor fault
F13 Storage tank temperature sensor fault
F20 Overheating fault
F22 Low water pressure
F23 Water circulation fault
F24 Water circulation fault
F26 Fault in gas valve
F27 Flame detection fault
F28 Ignition fault
F29 Loss of flame during operation
F32 Incorrect air pressure
F49 EBUS voltage fault
F61 Fault in the main board
F62 Fault in the main board
F63 Fault in the main board
F64 Fault in the main board
F65 Fault in the main board
F67 Fault in the main board
F68 Fluctuation of flame signal
F70 User interface incompatible with the main board
F71 Flow heating temperature sensor fault
F72 Permanent temperature difference between flow and return heating sensors
F73 Heating circuit pressure sensor fault
F74 Heating circuit pressure sensor fault
F76 Thermal fuse fault
F77 Fault in gas valve motor
F79 Storage tank temperature sensor fault
F81 Overheating of hot water circuit
F83 No water in the installation
F84 Permanent temperature difference between flow and return heating sensors
F85 Flow and Return heating sensor fault
F86 Underfloor heating contact fault
Err User interface fault

Ultracom cxi Range and Ultracom cx Range

CodesDescription
F1 Ignition fault
F3 Fan unable to reach ignition speed
F4 Ignition fault
F5 Overheat Fault
F6 Central heating flow thermistor
F9 Water pressure sensor fault, blocked flow filter or pump fault
F10 Central return flow thermistor
F11 Main board connection fault
F13 PCB memory or sensing fault
F14 Gas valve control defective
F15 E-bus voltage failure
F22 Low water pressure or ignition temperature rise too slow
F25 Circulation fault
F43 Generic error
F70 Software incompatible
F73 Unable to see pump activate
F77 Condensate pump error (optional)
No display or Er loose connection X51

Ultracom hxi Range

CodesDescription
F1 Ignition fault
F3 Fan unable to reach ignition speed
F4 Ignition fault
F5 Overheat Fault
F6 Central heating flow thermistor
F9 Water pressure sensor fault, blocked flow filter or pump fault
F10 Central return flow thermistor
F11 Main board connection fault
F13 PCB memory or sensing fault
F14 Gas valve control defective
F15 E-bus voltage failure
F22 Low water pressure or ignition temperature rise too slow
F25 Circulation fault
F43 Generic error
F70 Software incompatible
F73 Unable to see pump activate
F77 Condensate pump error (optional)
No display or Er loose connection X51

Ultracom sxi Range

CodesDescription
F1 Ignition fault
F3 Fan unable to reach ignition speed
F4 Ignition fault
F5 Overheat Fault
F6 Central heating flow thermistor
F9 Water pressure sensor fault, blocked flow filter or pump fault
F10 Central return flow thermistor
F11 Main board connection fault
F13 PCB memory or sensing fault
F14 Gas valve control defective
F15 E-bus voltage failure
F22 Low water pressure or ignition temperature rise too slow
F25 Circulation fault
F43 Generic error
F70 Software incompatible
F73 Unable to see pump activate
F77 Condensate pump error (optional)
No display or Er loose connection X51

Ultrapower sxi Range

CodesDescription
F1 Ignition fault
F3 Fan unable to reach ignition speed
F4 Ignition fault
F5 Overheat Fault
F6 Central heating flow thermistor
F9 Water pressure sensor fault, blocked flow filter or pump fault
F10 Central return flow thermistor
F11 Main board connection fault
F13 PCB memory or sensing fault
F14 Gas valve control defective
F15 E-bus voltage failure
F22 Low water pressure or ignition temperature rise too slow
F25 Circulation fault
F43 Generic error
F70 Software incompatible
F73 Unable to see pump activate
F77 Condensate pump error (optional)
No display or Er loose connection X51

Xtramax HE Range

CodesDescription
F1 Ignition fault
F2 Fan
F3 Fan
F4 Ignition fault
F5 Overheat Fault
F6 Central heating flow thermistor
F7 Domestic hot water thermistor
F8 Tank thermistor
F9 Water pressure sensor fault (please contact GW technical department for further information)
F10 Central return flow thermistor
F11 Main board connection fault
F12 User interface connection fault
F13 PCB memory or sensing fault
F14 Gas valve control defective
F16 Flame detection fault
F17 Power supply is less than 170v
F18 User interface fault
F19 Central heating thermistor unplugged
F20 Software incompatibility
F23 Water circulation fault
F24 Cental heating return temperature > 90 degrees
F25 Maximum temperature rise slope
F26 Maximum delta temperature

Xtrafast 96/120 Range and Xtrafast 96/120E1 Range

CodesDescription
F00 No fault
F02 Air flow fault
F04 Ignition fault - flame detection
F05 Overheating
F06 Central heating thermistor/wiring fault
F07 Domestic hot water thermistor/wiring fault
F08 Storage vessel thermistor/wiring fault
F09 System pressure sensor fault
F10 Fan fault
F11 Poor circulation
F12 User interface fault
F13 Main pcb fault
F14 Central heating flow temperature > 97 degrees
F15 Gas mechanism fault
F20 Communication fault