Vaillant Ecofit Pure - low pressure

[Kai1977]

I forgot to turn off the boiler before releasing air from the radiator today. Luckily heating was off and water was cold!

But now the boiler won't work and the water pressure has dropped to 0.8. Assume it's related to me clearing the air but not sure?

I've tried turning off the boiler and resetting it but it won't start up and displays an F.75 error.

Separately to this I've been hearing a water hammer sound whenever I turn on a tap, hot or cold, but this has been happening for over a week and I'm pretty sure it's because our neighbours have been doing some building work and our pipes are next to theirs.

 

[oldbuffer]

Re-pressurise the boiler to around 1.2 - 1.3 bar. When you bled the radiator(s) you will have lowered the pressure in the system. Depending on your boiler it will not run if the pressure is below a certain value.

 

[Kai1977]

Thank you, that's sorted it!

 

[CountryFan]

F75 is usually a pressure sensor fault or sometimes a pump fault. Don’t be surprised if it recurs.