Vitodens 200: What does the control panel pressure gauge measure; gas or water pressure?

[rlm]

The burner will not start.  It looks like the pressure gauge is measuring less than 0.8bar.   Is that water or gas pressure?

[Franky]

The manometer shows the filling pressure of the system.

[rlm]

So it's the water pressure (Wasserdruck) in the system.
OK, thanks. Now I know who to call.