Benchmark MAIN Installation & Service Instructions Manual page 42

Modulator
Wires
Ignition
Lead
Electrical Plug
Inlet Pipe
Gas Feed
Pipe
Fig. 65
Flow Pipe
Central Heating
Temperature Sensor
Safety Thermostat
Fig. 66
Return Heating
Temperature Sensor
Retaining Clip
42
© Baxi Heating UK Ltd 2007
Gas Valve
Heating Return Pipe
Fig. 67
14.0 Changing Components
14.8 Gas Valve (Fig. 65)
1. Undo the nut on the gas feed pipe under the boiler.
2. Completely undo the securing screws and hinge the facia
panel down.
3. Disconnect the wires from the valve modulator and the
ignition lead from the spark generator. Disconnect the
pressure sensing pipe from the valve. Undo the screw
securing the spark generator electrical plug to the valve and
disconnect the plug.
4. Pull the earth wire off the spade terminal on the valve.
5. Remove the screws securing the inlet pipe flange to the
boiler bottom panel and those securing the outlet manifold
to the burner manifold.
6. Remove the valve from the boiler.
7. Note the orientation of the inlet pipe and outlet
manifold. Undo the securing screws and remove the pipe
and manifold.
8. Examine the 'O' ring seals for damage, replacing as
necessary.
9. Fit the inlet pipe and outlet manifold to the new valve,
ensuring that the 'O' ring seals are in place.
10. Reassemble in reverse order and check the burner
pressure as described in Section 11.2.
14.9 Central Heating Temperature Sensor
(Fig. 66)
1. Ease the retaining tab on the sensor away and disconnect
the electrical plug.
2. Unscrew the sensor from it's pocket and reassemble in
reverse order. The plug will only fit one way.
14.10 Safety Thermostat
(Fig. 66)
1. Pull the electrical connections off the thermostat.
2. Remove the screws securing the thermostat to the
mounting plate on the flow pipe.
3. Reassemble in reverse order. The thermostat is not
polarised - either wire can fit either terminal on the
thermostat.
14.11 Return Heating Temperature Sensor
(Fig. 67)
1. Ease the retaining tab on the sensor away
and disconnect the electrical plug.
2. Prise the sensor retaining clip off the pipe and remove
the sensor from the clip.
3. Reassemble in reverse order.