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

SERVICE AND SPARES

6.8.6 GAS VALVE

Refer to figure 96
▶ 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. 96 Gas valve upper connection
Refer to figure 97
1. Undo bottom gas connection to gas valve.
2. Undo two securing screws on the underside of casing.
▶ Pull valve up and forward out of boiler.
▶ Disconnect electrical connections.
▶ Replace valve with new seals and check for gas tightness.
2.
Fig. 97 Gas valve lower connection
NOTICE: The valve will require setting; follow
procedure "Setting the air/gas ratio".

6.8.7 AIR/GAS MANIFOLD AND FAN ASSEMBLY

The following components require the
air/gas manifold and fan assembly to be removed:
▶ Fan electrode assembly
▶ Burner
▶ Heat exchanger
42
1.
6720643895-72.1Wo
1.
NOTICE:
▶ If the joint between the Air/Gas manifold and heat
exchanger is disturbed the sealing gasket must be
replaced.
▶ 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.
▶ Remove electrical connector from fan.
▶ Remove wire clip from gas valve outlet then pull the gas pipe free from
gas valve (see figure 96).
Fig. 98 Retaining plate assembly
▶ Undo the securing nut at the top of the heat exchanger and remove the
retaining plate assembly.
Disconnect spark electrodes and flame sensor
connection.
This will prevent damage to the electrodes and sensor
when the air/gas manifold is rotated.
▶ Rotate fan and air/gas manifold assembly (1.) around the top of the
heat exchanger until the lug on the air/gas manifold is visible.
1.
Fig. 99 Rotate the air/gas manifold assembly
▶ Lift up assembly and remove from boiler.
NOTICE: After re-assembly, check the CO/CO
described in section 6.6 Setting the air/gas ratio.
1.
levels as
2
6 720 802 047 (2013/05)