Gas Valve; Air/Gas Manifold And Fan Assembly - Bosch WORCESTER GREENSTAR Ri ErP Series Installation, Commissioning And Servicing Instructions

7.8.6 GAS VALVE

▶ Isolate gas supply at boiler gas cock.
1. Refer to figure 72 and re move the wire clip from the 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. 72 Gas valve upper connection
1. Refer to figure 73 and undo bottom gas connection to gas valve.
2. Undo two securing screws on the underside of casing.
▶ Disconnect electrical connections.
▶ Pull valve up and forward out of boiler.
▶ Replace valve with new seals and check for gas tightness.
2.
Fig. 73 Gas valve lower connection
NOTICE: The valve will require setting; follow
procedure "Setting the air/gas ratio".

7.8.7 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
NOTICE:
▶ If the joint between the Air/Gas manifold and heat
exchanger is disturbed sealing gasket must be
replaced.
▶ After re-assembly the 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.
Greenstar Ri ErP - 6 720 813 283 (2016/07)
1.
6720643895-72.1Wo
1.
▶ Remove electrical connector and earth wire the from fan.
▶ Remove wire clip from gas valve outlet then pull gas pipe free from the
gas valve (see figure 72).
2.
1.
Fig. 74
▶ 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.
1. 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.
▶ Lift up assembly and remove from boiler.
1.
Fig. 75 Rotate the air/gas manifold assembly
NOTICE: After re-assembly, check the CO/CO
described in section 7.6 Setting the air/gas ratio.
SERVICE AND SPARES
3.
6720804530-16.1Wo
levels as
2
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