10. Flame Sensor.
Refer to Fig. 32.
Remove the burner as described in Sections 15.3, h and 16.4.7.
Undo the M3 screw and remove the sense electrode from the burner.
Fit the replacement electrode in the reverse order, checking that
the sense gap is 5 to 6mm.
11. Gas Valve.
Refer to Fig. 28.
Check that the electricity and gas supplies to the appliance are
turned off.
Hinge down the facia panel into the servicing position as
described in Section 15.3, c.
Remove the air pressure switch bracket as described in
Section 16.4. 2.
Undo the two G
3
⁄
4
inch nuts on the gas valve and the two M4
screws on the gas valve bracket and withdraw the valve.
Whilst supporting the valve carefully pull off the three electrical
solenoid plug connections.
Fit the replacement gas valve in the reverse order ensuring the
sealing washers are correctly fitted.
Turn on the gas supply and check for soundness.
To set the burner pressure.
Refer to Fig. 28.
The minimum and maximum burner pressure must be set after a
new gas valve has been fitted.
Follow the procedure described in Section 13.4 - Appliance Operation.
The minimum burner pressure must be set first since
maximum is adjusted simutaneously.
Start the appliance in the domestic hot water mode as described
in Section 13.4. - Appliance Operation.
Turn the gas mode switch on the rear of the facia to minimum.
Refer to Fig. 26.
Adjust the minimum pressure screw on the gas valve to give a
burner pressure of 1.5mbar (24CDi) or 1.0mbar (28CDi) or 3.1
mbar (35CDi
II
) for natural gas or 5.4mbar (24CDi) or 3.8mbar
(28CDi) or 3.1mbar (35CDi
II
) for propane.
Turn the gas mode switch on the rear of the facia to maximum.
Adjust the maximum pressure screw on the gas valve to give a
burner pressure of 14.8mbar (24CDi) or 15.5mbar (28CDi) or
13.5mbar (35CDi
II
) for natural gas or 35.5mbar (24CDi) or
35.5mbar (28CDi) or 34.7mbar (35CDi
II
) for propane.
Turn the gas mode switch on the rear of the facia to normal.
After completing the adjustments, check the minimum and
maximum pressures and adjust as necessary.
28CDi/35CDi
II
ONLY:
Ensure the appliance lights in the central
heating mode. Turn the CH pressure adjuster on the rear of the
control board (Fig. 26) fully clockwise, wait until the pressure
stops increasing and then
slowly
turn it anti-clockwise until the
burner pressure is 10.8mbar natural gas or 24.3mbar propane for
28CDi or 8mbar natural gas or 21.3mbar propane for 35CDi
II.
After completing the adjustments, check the minimum and
maximum pressures and adjust as necessary.
It should not be necessary to alter the central heating
potentiometer setting when the gas valve only is replaced and
the minimum and maximum pressures are set.
23
Fig. 36. Appliance Components (lower assembly)
Domestic hot water sen-
sor (not shown) located
behind water to water heat
exchanger
Circulating pump
Flow pipe from pump and
union connection
Expansion vessel
Air pressure switch
Gas valve
Water to water
heat exchanger
Pressure relief
valve
Drain tap
(C.H. Return)
Pressure Gauge
Facia and controls shown
in the service position
Plastic water
cover
Filling loop
Water diverting valve
and micro switch
assembly
Drain tap C.H. flow
Содержание 24CDi
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