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57 THERMOSTAT CONTROL, THERMISTOR SENSOR LEAD and ON/OFF SWITCH
REPLACEMENT
Refer also to Frame 54.
Remove the control box fixing screw (B). Pull the
box forward and downward to disengage.
Thermostat control
1. Pull the knob off the shaft.
2. Remove the backnut securing the thermostat
control to the control box.
3. Pull off the Molex connector from the printed
circuit board.
4. Replace and re-assemble in reverse order.
Thermistor sensor lead
5. Pull the sensor lead connector off the printed
circuit board.
6. Remove the sensor from the heat exchanger
pocket and unclip from the back panel.
7. Remove the strain relief bush from the back
panel base.
8. Remove the sensor lead through the grommet in
the control box.
9. Replace and re-assemble in reverse order.
On/off switch
10. Disconnect the electrical connectors from the
rear of the switch.
11. Press in the 2 side retaining clips and remove
the switch.
12. Re-assemble in reverse order.
58 PILOT BURNER REPLACEMENT
1. Refer to Frame 54.
2. Remove the burner and air box assembly.
Refer to Frame 49.
3. Remove the electrode retaining nut and remove the pilot
shield and electrode.
4. Unscrew the central pilot fixing screw and lift the pilot clear
of the pilot injector. The pilot injector may now be
unscrewed if required.
5. Replace the pilot burner (injector if necessary) and retain
with the M4 screw previously removed. Ensure that the
Henrad WH
LXFF, FF
SERVICING
-
Installation
copper sealing washer is replaced when refitting the pilot
injector.
6. Replace the electrode and pilot shield, retaining both with
the electrode nut. Check the spark gap.
7. Replace the box assembly.
8. Replace the burner.
9. Replace the boiler casing.
10. The pilot is factory set to maximum and no further
adjustment is possible. Ensure that there is an inlet
pressure of 20 mbar available. Also check burner ignition
and cross-lighting.
29
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