What does the Viessmann Vitodens 111-W F44 fault code mean?
The F44 fault code on the Viessmann Vitodens 111-W indicates a problem with the secondary heat exchanger, which is responsible for transferring heat from the boiler to the domestic hot water supply. This fault can lead to reduced efficiency and hot water supply issues.
Common Causes
- Blocked Heat Exchanger: Debris or limescale buildup can obstruct the flow of water, affecting heat transfer.
- Faulty Temperature Sensors: Malfunctioning sensors may incorrectly report temperatures, leading to operational issues.
Can I fix it myself? (DIY)
It is highly recommended to call a qualified Gas Safe Engineer to address this issue, as working on gas appliances can be dangerous and requires professional expertise.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for replacing the secondary heat exchanger is around £600 to £800. This includes parts and labour, as the heat exchanger is a significant component that requires professional installation.