30
British Gas 440 - 480 RD2 -
Installation & Servicing
SERVICING
48 BURNER AND CONTROLS ASSEMBLY REMOVAL
49 CLEANING THE BURNER/PILOT ASSEMBLY
50 CLEANING THE FAN/FLUE WAYS
Note.
Brushes with metallic bristles MUST NOT be used.
1. Brush off any deposits that may have fallen onto the burner
head (ensuring that the flame ports are unobstructed) and
remove any debris that may have collected.
2. Remove the main burner injector. Check, clean or replace,
as required.
3. Refit the injector, using an approved jointing compound.
4. Inspect the pilot burner and ignition/detection electrode;
ensure they are clear and in good condition.
Check that:
a. The HSI and detection electrodes are clean and
undamaged.
b. The HSI and detection leads are in good condition.
c. The position of the HSI and detection electrodes
relative to the burner are correct. Refer to Frames 54
& 57.
5. Clean or renew components as necessary.
1. Remove the control box cover.
2. Unplug the HSI lead from the PCB and withdraw it from the
box.
3. Disconnect the detection lead from the electrode.
4. Remove the screw securing the control box to the
baseplate, slide to the left to release and place to one side.
5. Undo the gas service cock union.
6. Remove the 4 wing nuts and withdraw the burner and
controls assembly, complete, from the boiler.
7. Place on a convenient working surface.
1. Remove the silicon rubber tube from the fan pressure
sensing point.
2. Disconnect the fan leads.
3. Remove the screw and withdraw the fan thermistor
sensor from the scroll.
4. Disconnect the silicon rubber tube from the top of the
collector hood.
5. Remove the 4 M4 screws on the top of the collector
hood and by sliding it forwards remove collector hood/
fan assembly.
6. Check that the fan impeller runs freely. Remove any
debris from the impeller with a soft brush.
7. Remove the flue baffles.
8. Remove all loose deposits from the heat exchanger,
particularly between the fins, using a suitable brush.
9. Reassemble in reverse order. Lubricate fan 'O' ring
with silicon grease. Ensure the fan leads, 2 sensing
tubes and fan sensor are reconnected.
Mex
1892
440 & 450 FF Only
SER
VICING