Viessmann Vitopend 100-W Installation And Service Instructions Manual page 54

Commissioning, inspection, maintenance
Further details regarding the individual steps
1. Switch the control unit on and close
the gas shut-off valve.
2. Use / to select "IF00"
The main display shows the current
pressure in MPa.
3. Drain the system as much as possi-
ble or close the cap valve on the
expansion vessel. Relieve pressure
until 0 MPa is displayed.
4.
A
If the pre-charge pressure of the expan-
sion vessel is lower than the static sys-
tem pressure, top up with nitrogen at
test connector A until the pre-charge
pressure is 0.01 to 0.02 MPa higher
than the static system pressure.
54
(cont.)
5. Top up with water (see page 34)
until the charge pressure of the
cooled system is at least 0.08 MPa,
and is 0.01 to 0.02 MPa higher than
the pre-charge pressure of the
expansion vessel.
Permiss. operating pressure:
(0.3 MPa)