BoilerFaultCodes 00
Your boiler is operating normally and there are no faults currently detected by the system.
Glow-worm Xtrafast 96 120 Fault codes & diagnostics
12 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Combi Natural Gas 35-37 kW 2001-present
GC Number 47-047-25
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Severity at a glance
Each cell = one fault code. Hover to identify. 10 High
1 Medium
1 Low
Just want the most common Glow-worm Xtrafast 96 120 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 12 documented codes
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02 Your boiler has stopped working because the fan system cannot properly clear waste gases or bring in fresh air to burn fuel safely.
Your boiler has stopped working because the fan system cannot properly clear waste gases or bring in fresh air to burn fuel safely.
Parts commonly replaced
- Fan motor
- Air pressure switch
- Venture tube
Related codes
04 Your boiler is failing to light the flame needed to heat your water and radiators.
Your boiler is failing to light the flame needed to heat your water and radiators.
What to check first
- Check that your gas pre-payment meter hasn't run out of credit
- Ensure other gas appliances in your home, like a hob, are receiving gas
- Press the 'Reset' button on the boiler control panel to see if it restarts
Parts commonly replaced
- Ignition Electrode
- Flame Sensing Electrode
- Gas Valve
Related codes
05 Your boiler has got too hot and has shut itself down as a safety precaution to prevent damage.
Your boiler has got too hot and has shut itself down as a safety precaution to prevent damage.
What to check first
- Check that all radiator valves are fully open (especially TRVs)
- Ensure there is enough water pressure in the system (typically 1.0 to 1.5 bar)
- Press the reset button once the boiler has had time to cool down
Parts commonly replaced
- Overheat Thermostat
- Circulation Pump
- Main Heat Exchanger
Related codes
06 Your boiler has detected a problem with the internal sensor that monitors the temperature of your heating water, meaning the system cannot run safely.
Your boiler has detected a problem with the internal sensor that monitors the temperature of your heating water, meaning the system cannot run safely.
Parts commonly replaced
- Central heating NTC thermistor
- Wiring harness connectors
Related codes
07 Your boiler has stopped providing hot water because the internal sensor responsible for measuring water temperature has either failed or has a loose connection.
Your boiler has stopped providing hot water because the internal sensor responsible for measuring water temperature has either failed or has a loose connection.
Parts commonly replaced
- DHW Thermistor (NTC Sensor)
- Wiring Harness
Related codes
08 Your boiler has lost its ability to monitor the temperature of the stored hot water, meaning it cannot heat your water reliably or safely.
Your boiler has lost its ability to monitor the temperature of the stored hot water, meaning it cannot heat your water reliably or safely.
Parts commonly replaced
- Storage vessel NTC thermistor
- Wiring harness
Related codes
09 Your boiler's internal sensor is struggling to accurately read the water pressure, which prevents the system from operating safely.
Your boiler's internal sensor is struggling to accurately read the water pressure, which prevents the system from operating safely.
Parts commonly replaced
- System pressure sensor
- Sensor wiring harness
Related codes
12 Your boiler's control panel and its internal computer are having trouble communicating with each other, preventing the unit from starting.
Your boiler's control panel and its internal computer are having trouble communicating with each other, preventing the unit from starting.
Parts commonly replaced
- User Interface PCB
- Main Control PCB
- Connection Wiring Loom
13 Your boiler's internal computer has developed a fault and can no longer control the system safely.
Your boiler's internal computer has developed a fault and can no longer control the system safely.
Parts commonly replaced
- Main PCB (Printed Circuit Board)
- Wiring Harness
Related codes
14 Your boiler has shut down because a sensor has detected that it is getting far too hot, likely due to a circulation problem.
Your boiler has shut down because a sensor has detected that it is getting far too hot, likely due to a circulation problem.
Parts commonly replaced
- Circulation Pump
- Flow NTC Sensor
- Main Heat Exchanger
Related codes
20 Your boiler's internal computer parts are struggling to talk to each other, which prevents the system from starting up normally.
Your boiler's internal computer parts are struggling to talk to each other, which prevents the system from starting up normally.
Parts commonly replaced
- Main PCB
- User Interface Display PCB
- Wiring Harness
Related codes
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