Draining The Boiler Or Heating System; Checking And Cleaning The Burner - Viessmann Vitopend 100-W Installation And Service Instructions For Contractors

Further details regarding the individual steps
11. Open the gas shut-off valve and
start the appliance.

Draining the boiler or heating system

!
Please note
Risk of scalding
Only drain the boiler or heating
system when the boiler water or
cylinder temperature has drop-
ped below 40 °C.

Checking and cleaning the burner

Turn off the ON/OFF switch on the con-
trol unit and the power supply.
Commissioning, inspection, maintenance
(cont.)
Danger
Gas escaping from the test
connector leads to a risk of
explosion.
Check the test connector for
gas tightness.
Note
The boiler or heating system can only be
drained if the servomotor of the diverter
valve is in its centre position (see
page 18). As soon as the servomotor of
the diverter valve is in its centre position,
turn off the ON/OFF switch on the control
unit to prevent the pump from running
dry.
Close the gas shut-off valve and safe-
guard against reopening.
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