28
2000225065A
12 Servicing
12.1 General
Refer to Table 2 Section 1 General Information. Measurement
of the products of combustion can be achieved by connection
of a probe to the combustion analyser test point, see diagram
12.1.
Before commencing with a service or replacement of parts the
boiler should be isolated from the electrical supply and the gas
supply should be turned off at the gas isolation valve, see
diagram 8.1.
All routine servicing requirements can be achieved by the
removal of the front panel and inner panel only. To remove
simply undo the two screws on the underside of the front panel
and lift off, see diagram 6.3. Undo the two screws on the front
of inner panel and lift off, see diagram 6.3.
Unless stated otherwise any part removed during servicing
should be replaced in the reverse order to removal.
Servicing should always include the removal of any debris from
the condensate pipe and siphon.
After completing any servicing of gas carrying components,
ALWAYS test for gas soundness and carry out a functional test
of the controls.
12.2 Spark Electrode
Disconnect the electrode lead and two securing screws.
Withdraw the spark electrode carefully from the combustion
chamber, see diagram 12.2 and 12.5.
Inspect the tips for damage.
Clean away any debris and check the spark gap is 3.5 to 4.5
mm.
Check the electrode gasket for signs of damage and replace if
necessary.
12.3 Burner
Drop down the control panel into the service position, see
diagram 12.13.
Disconnect the gas supply at the gas service cock, see diagram
8.1.
Remove the two gas pipe retaining clips, one located below gas
valve and the other one located on the underside of the boiler
chassis, see diagram 12.4.
Pull sealing grommet down gas pipe, see diagram 12.4.
Push the gas pipe upwards further into gas valve connection
and then rotate anti-clockwise (looking down) until the gas pipe
end is over the large hole in boiler chassis, see diagram 12.4.
Withdraw the gas pipe from gas valve connection and remove.
Note: When replacing ensure that the sealing grommet, situated
below the gas valve is correctly re-seated.
Disconnect the gas control valve electrical plug at the gas
control valve.
Disconnect the electrical leads from the fan.
Remove the five combustion chamber front retaining nuts, see
diagram 12.5.
Gently remove the fan, gas control valve and burner assembly
from the combustion chamber, see diagram 12.3.
SECURING
SCREW 2 OFF
SPARK
GAP 3.5 to 4.5
Diagram 12.2
HEAT
EXCHANGER
ELECTRODE
GASKET
Diagram 12.1
COMBUSTION
ANALYSER
TEST POINT
FLUE
ELBOW
Diagram 12.3
BURNER
COMBUSTION CHAMBER
FAN
GAS CONTROL
VALVE
SEALING
RING
EARTH LEAD
11410
11484
11502
