What does the Vaillant Home F78 fault code mean?
The F78 fault code on a Vaillant Home boiler indicates a system ignition fault, which means the boiler is unable to ignite the burner. This can prevent the heating and hot water from functioning properly.
Common Causes
- Insufficient Gas Supply: A blockage or issue with the gas supply can prevent the boiler from igniting.
- Faulty Ignition Electrode: If the ignition electrode is damaged or malfunctioning, it may fail to create the spark needed for ignition.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for any gas or electrical issues, as attempting to fix these problems without proper training can be dangerous.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving an F78 fault could be around £150 to £250, depending on whether the ignition electrode needs replacing or if there are issues with the gas supply that require further investigation.