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7. Parts replacement
IMPORTANT:
Before starting any maintenance
work:
•
Isolate the mains electricity supply
by disconnecting the plug at the
socket outlet (if there is an isolating
switch only, remove the fuse from
the switch).
•
Turn OFF the gas supply at the gas
service valve fitted to the boiler.
•
When removing any water carrying
components ensure that the control
box cover and terminal box cover
are in position and water is kept
away from all electrical compo-
nents.
•
Always test for gas soundness and
always carry out functional checks
after any service work and after
exchanging any gas carrying
component.
•
Always check earth continuity,
polarity and resistance to earth with
a multimeter after any service work
and after exchanging any elec-
trical component.
7.1 Initial preparation
(These initial preparation procedures
need only be carried out where speci-
fically mentioned in the individual
component replacement procedures).
