What does the Glow-worm Energy F39 fault code mean?
The F39 fault code indicates a system pressure fault, which typically means that the boiler’s water pressure is either too low or too high. This can lead to inefficient operation or potential damage to the system if not addressed promptly.
Common Causes
- Low Water Pressure: This can occur due to leaks in the system, a faulty pressure relief valve, or insufficient water supply.
- High Water Pressure: This may be caused by a malfunctioning pressure reducing valve or issues with the expansion vessel.
Can I fix it myself? (DIY)
You can attempt to check and adjust the system pressure by using the filling loop to add water if it’s low. However, if the pressure is high or if you suspect a leak or other serious issue, it is essential to call a Gas Safe Engineer to avoid any safety risks.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for addressing a pressure fault could range from £150 to £300, depending on whether it requires a simple adjustment or the replacement of components like the pressure relief valve or expansion vessel.