35
British Gas 4100 & 4125 RD2 -
Installation & Servicing
SERVICING
62 AIR PRESSURE SWITCH (APS) REPLACEMENT
1.
Remove the lower front panel, control panel and
the top panel. Refer to Frame 47.
2.
Remove the APS fixing screw.
3.
Remove both sensing tubes from the APS.
4.
Remove the 3 electrical connections from the
APS.
5.
Fit the new APS and reassemble in reverse order.
6.
Check the operation of the boiler .
1.
Remove the lower front panel and grille
assembly. Refer to Frame 47.
2.
Remove the burner and controls assembly.
Refer to Frame 57.
3.
Unscrew the gas inlet pipe from the valve.
4.
Remove the 4 securing screws and withdraw
the valve from the burner manifold.
5.
Fit the new gas valve, ensuring that:
a.
The valve is fitted the correct way round -
an arrow engraved on the valve indicates
the direction of flow.
b.
The sealing 'O' ring supplied with the
valve is correctly fitted at the outlet
flange.
c.
An approved jointing compound is used
when reconnecting the gas inlet pipe.
6.
Reassemble in reverse order.
7.
Check the operation of the boiler.
60 GAS VALVE REPLACEMENT
1.
Remove the lower front panel, control panel and top panel. Refer to
Frame 47.
2.
Remove the silicon rubber tube from the fan pressure sensing point.
3.
Disconnect the fan leads.
4.
Remove the securing screw and withdraw the fan thermistor sensor
from the scroll.
5.
Disconnect the silicon rubber tube from the top of the collector hood.
6.
Remove the 4 M4 screws on the top of
the collector hood and by sliding it
forwards remove collector hood / fan
assembly.
7.
Remove the three M4 screws retaining
the fan to the collector hood.
8.
Fit the new fan and re-assemble in
reverse order. Lubricate fan 'O' ring
with silicon grease. Ensure the fan
leads, 2 sensing tubes and fan sensor
are reconnected.
9.
Check the operation of the boiler.
61 FAN REPLACEMENT
SER
VICING
