What does the Glow-worm Betacom F33 fault code mean?
The F33 fault code on a Glow-worm Betacom boiler indicates a high limit thermostat fault, which typically means that the boiler has overheated or that there is a malfunction in the thermostat itself. This safety feature prevents the boiler from operating under unsafe conditions.
Common Causes
- Overheating: This can occur due to insufficient water flow, blocked pipes, or a malfunctioning pump.
- Faulty Thermostat: A defective high limit thermostat may not accurately read the temperature, causing the boiler to shut down.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for this fault, as it involves gas and electrical components that can be dangerous if handled improperly. Attempting to fix it yourself could void warranties or lead to further issues.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving an F33 fault could be around £150 to £250, depending on whether the high limit thermostat needs replacing or if additional repairs are required to address overheating issues.