What does the Glow-worm Ultimate F101 fault code mean?
The F101 fault code indicates a domestic hot water (DHW) pressure warning, which suggests that the pressure in the system is too low for the boiler to operate effectively. This can lead to insufficient hot water supply and may require immediate attention to prevent further issues.
Common Causes
- Low Water Pressure: This is often due to leaks in the system or insufficient water supply, which can cause the pressure to drop below the operational threshold.
- Faulty Pressure Relief Valve: A malfunctioning pressure relief valve may not maintain the correct pressure, leading to the F101 fault code being triggered.
Can I fix it myself? (DIY)
You can attempt to fix low water pressure by checking the pressure gauge on your boiler and using the filling loop to add water if necessary. However, if you suspect a leak or a faulty component, it is crucial to call a Gas Safe Engineer to ensure safety and compliance with regulations.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for addressing the F101 fault code could be around £150 to £250, primarily depending on whether a pressure relief valve replacement is needed, which typically costs around £100 to £150 including parts and labour.