What does the Viessmann Vitodens 100-W F98 fault code mean?
The F98 fault code on the Viessmann Vitodens 100-W indicates a malfunction in the energy monitoring system, which is responsible for tracking the boiler’s efficiency and performance. This issue can lead to improper operation of the boiler and may affect heating and hot water supply.
Common Causes
- Faulty Energy Meter: The energy meter may be defective or malfunctioning, leading to incorrect readings and triggering the fault code.
- Wiring Issues: Damaged or loose wiring connections within the energy monitoring system can disrupt communication and cause the F98 error.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for this issue, as it involves electrical components and safety concerns. Attempting to fix it yourself may void the warranty or lead to further complications.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F98 fault code is around £150 to £250. This includes diagnostics and potential replacement of the energy meter or repair of wiring, which are the most likely causes of the fault.