Gas Valve; Air/Gas Manifold And Fan Assembly - Worcester GREENSTAR 24i Junior Installation Instructions Manual

6.8.6

GAS VALVE

Refer to figure 90
B Isolate gas supply at boiler gas cock.
1. Remove wire clip from gas valve outlet.
2. Pull the gas pipe free from the gas valve.
If the pipe will not pull out, unscrew the nut to aid
removal.
2.
Fig. 90 Gas valve upper connection
Refer to figure 91
1. Undo bottom gas connection to gas valve.
2. Undo two securing screws on the underside of casing.
B Pull valve up and forward out of boiler.
B Disconnect electrical connections.
B Replace valve with new seals and check for gas
tightness.
2.
Fig. 91 Gas valve lower connection
NOTICE: The valve will require setting;
follow procedure "Setting the air/gas ratio".
6 720 644 741a (2010/10)
1.
6720643895-72.1Wo
1.
6.8.7

AIR/GAS MANIFOLD AND FAN ASSEMBLY

The following components require the
air/gas manifold and fan assembly to be
removed:
B Fan electrode assembly
B Burner
B Heat exchanger
NOTICE:
B If the joint between the Air/Gas manifold
and heat exchanger is disturbed the
sealing gasket must be replaced.
B After re-assembly, combustion must be
checked using the procedure in the
section "Setting the Air/Gas ratio".
Measurement and setting (if necessary)
of the gas ratio must not be attempted
unless the person is equipped with a
combustion analyser conforming to BS
7927 and is competent in its use.
B Remove electrical connector from fan.
B Remove wire clip from gas valve outlet then pull the
gas pipe free from gas valve (see figure 90).
Fig. 92
B Undo the securing nut at the top of the heat
exchanger and remove the retaining plate assembly
(1).
Disconnect spark electrodes and flame
sensor connection.
This will prevent damage to the electrodes
and sensor when the air/gas manifold is
rotated.
SERVICE AND SPARES
1.
53