Viessmann Vitodens 100 WB1A Installation And Service Instructions Manual page 50

Installation
Commissioning and testing
Venting the boiler by flushing out (after venting system)
50
(cont.)
1. Leaving the hose connections from
filling the system continue to fil the
biler from the external filling loop
and draininig the ewater to a drain
from connection D.
2. Continue flushing the water through
the boiler until no air pockets are
discharged out of the drain hose.
3. Slowly turn off the valve D and
turn off the temporary filling loop to
regulate the pressure in the boiler
and system to approx 1.2 bar.
4. Turn valve A to open position
(toggle to rear).
5. Turn on the appliance to circulate
the pump in both DHW and CH
positions in order to continue vent-
ing. Continue venting and reverse
the filling procedure if required.
Note: It is essential that there is
no air in the heat exchanger and
the system prior to firing the
appliance. This will caus en F1
fault and prevent you finishing
the installation without hinder-
ance.
6. Turn off shut off valves (C and D)
when the biler is vented and filled
fully
7. Turn boiler isolation valves A and
B to operating position (toggle to
the back), seal with the caps pro-
vided.