What does the Viessmann Vitodens 100-W F22 fault code mean?
The F22 fault code indicates a dry fire condition or low pressure within the system. This typically means that the boiler is unable to detect sufficient water pressure, which can lead to overheating and potential damage.
Common Causes
- Low Water Pressure: This can occur due to leaks in the system or insufficient water supply, causing the pressure to drop below the operational threshold.
- Air in the System: Trapped air can prevent proper water circulation, leading to low pressure and triggering the F22 fault code.
Can I fix it myself? (DIY)
You can attempt to reset the boiler and check the pressure gauge. If the pressure is below 1 bar, you can top it up using the filling loop. However, if you are unsure or if the issue persists, it is crucial to call a Gas Safe Engineer to avoid any safety risks.
Estimated Repair Cost (2026 UK Prices)
The estimated cost for addressing the F22 fault, including potential pressure adjustments and system checks, is around £150. This includes the cost of a Gas Safe Engineer’s visit and any minor repairs or adjustments needed to restore proper function.