30
British Gas 4100 & 4125 RD2 -
Installation & Servicing
SERVICING
48 BURNER AND CONTROLS ASSEMBLY REMOVAL
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 impellor runs freely. Remove any
debris from the impellor 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.
Re-assemble in reverse order. Lubricate fan 'O' ring with
silicon grease. Ensure the fan leads, 2 sensing tubes and
fan sensor are reconnected.
49 CLEANING THE BURNER ASSEMBLY
Note.
Brushes with metallic bristles MUST NOT be used.
1.
Brush off any deposits that may have fallen onto the
burner heads (ensuring that the flame ports are
unobstructed) and remove any debris that may have
collected.
2.
Remove the main burner injectors .Check, clean or
replace, as required.
3.
Refit the injectors, using an approved jointing
compound.
4.
Inspect the ignition/detection electrodes; 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 Frame 54 &
57.
5.
Clean or renew components as necessary.
50 CLEANING THE FAN/FLUEWAYS
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.
SER
VICING
