Vaillant ecotec 637 F75 fault

My boiler fails to come on in the morning with an F75 fault. The pressure has dropped to 0.8 bar, so i top it up to 1.0 bar and the boiler starts.

This procedure has been repeated every morning for the past 4 days, where is the the water going that i’m topping it up with and can you come and fix it?



Hi Dennis,

The F.75 Fault code is a common fault with the EcoTEC series.  We have covered this in a previous FAQ, please find link below:

F.75 Fault Code