Vaillant ecoTEC plus

[Jeannie920]

I'm house sitting whilst my son is on holiday. He has the above gas boiler. He showed me how to turn the heating on if it got cold but I messed up when I turned the heating back off. Now I can't get any hot water. All I have are flashing symbols on the left hand display. It's flashing F.75 and 0.5 and there is a C . Can anyone help please?

 

[Dan Robinson]

You need to top the pressure up.

Look for a filling loop which may be built into the underside of the boiler.

 

[DP]

Follow a 'wire knitted' pipe under the boiler, Dan refers to this a a filling loop ( picture on the right)
You should see two toggles as seem above the white line. Left toggle is open, right is closed.
If I wanted to add water to the system, I would turn the right hand toggle to raise the system pressure to similar as in first picture