How to diagnose failed expansion vessel and how to replace expansion vessel on a Vaillant Eco tec boiler step by step
This video is for GAS SAFE ENGINEERS only, always follow manufacturer instructions.
Before to start any work on gas appliance isolate the power, turn off the gas and the waters.
1. Remove front cover
2. Download manual
www.vaillant.co.uk/downloads/...
3. Drain the boiler
4. Leave open the drain point
5. Undo the expansion vessel nut
6. Remove expansion vessel bracket
7. Replace expansion vessel
8. Fit bracket and connect expansion vessel nut
9. Close the drain point.
10. Re-pressurise the heating system till 1 - 1.5 bar.