36
1
5
4
3
2
6
fig. 59
GW 643/1
1
1
2
2
fig. 60
Gasventil
7.6 Replacement of NTC
temperature sensor
Note: The NTC temperature sensor is
an extremely reliable component and
as such is unlikely to fail. Before
changing the NTC please check that
it is defective - see section 8 - fault
finding.
•
Disconnect boiler from electricity
supply.
•
Remove front casing as in section
7.1.3 and remove combustion
chamber cover as in section 7.1.5
•
Pull off connecting wire to sensor.
•
Unscrew NTC sensor. (4, fig 62)
•
Reassemble in reverse order.
•
Carry out electrical checks (see
section 5.1).
7.7 Replacement of gas valve
•
Isolate the boiler from the electrical
supply
•
Remove the front casing as in
section 7.1.3
•
Lower front control panel as in
section 7.1.6
•
Turn off the gas service valve (1,
fig. 50)
•
Loosen screw (1, fig. 59) and pull
off rectifier plug (2, fig. 59) from
the gas operator.
•
Pull off modulating coil wires (3,
fig. 59).
•
Disconnect air tube from gas
operator (4, fig. 59).
•
Remove two screws (5, fig. 59) at
burner inlet connection.
•
Remove screw (6, fig. 59) from gas
valve inlet connection.
•
Rotate gas valve to left and then lift
to remove.
•
Remove both inlet and outlet
connections from the gas valve (1,
fig. 60) by removing the eight
securing screws (2, fig. 60) and
refit to new gas valve using new
seals provided.
•
Reassemble in reverse order.
•
Set burner pressure in accordance
with instructions supplied with spa-
re part.
•
Carry out electrical checks (see sec-
tion 5.1) and test all gas joints for
soundness.
