Viessmann VITODENS 111-W Installation And Service Instructions Manual page 15

Mounting the boiler and making connections
3. Note
Only remove the locking clip under the gas pipe
union nut once the appliance has been installed.
Locking clip is no longer required.
(cont.)
4. Tighten union nuts so that they form a tight seal.
Tighten the union nuts as tightly as necessary and
ensure that the components are undamaged and
are functioning correctly throughout service life.
Observe torque settings if a torque wrench is avail-
able.
Check for gas tightness to BSI 6891.
Torque for union nuts
■ G : 24 Nm
½
■ G : 30 Nm
¾
When carrying out any work on gas connection fit-
tings, counterhold with a suitable tool. Never trans-
fer any forces to the internal components.
Installation sequence
15