Benchmark Alpha CD18S Installation And Servicing Instructions page 28

8.17 COMBUSTION CHAMBER INSULATION
Gain access to the combustion chamber as described in Section 8.1.
Front insulation - see Fig. 26
1. Remove the electrodes from the combustion chamber front as described in Section 8.3.
2. Remove the four screws securing the burner.
3. Carefully remove the insulation.
Back insulation - see Fig. 30
1. Remove the combustion chamber front/burner assembly.
2. Remove the centre screw retaining the insulation.
3. Carefully remove the insulation, suction applied to the centre of the insulation will aid this.
Fit a new panel and re-assemble in reverse order.
Refill and pressurise the system. (Refer to Commissioning, Section 5.1).
8.18 PRESSURE GAUGE - Fig. 31
1. Gain access behind the casing and drain the boiler heating circuit as described in Sections 8.1 and 8.2.
2. Remove the nut securing the pressure gauge sensor and withdraw the sensor.
3. Depress the two lugs on the pressure gauge and push it out of the control panel.
4. Fit the new gauge using a new washer on the manifold connection if necessary.
5. Refill and pressurise the system. (Refer to Commissioning, Section 5.1).
8.19 PRIMARY TEMPERATURE SENSOR - Refer to Fig. 27
1. Gain access as described in Section 8.1 behind the room sealed chamber panel and drain the heating circuit as described
in Section 8.2.
2. The primary sensor is positioned on the right hand side of the heat exchanger, see Fig. 27. Disconnect the wiring and
unscrew the sensor. Re-assemble in reverse order with a new sensor and sealing washer.
8.20 AUTOMATIC AIR VENT - Fig. 31
1. Gain access behind the casing and drain the boiler heating circuit as described in Sections 8.1 and 8.2.
2. Unscrew the automatic air vent from the pump outlet. Fit a new one using a new 'O' ring.
3. Refill and pressurise the system. (Refer to Commissioning, Section 5.1).
Primary pressure switch
Pressure gauge
Fig. 31
Alpha CD18S/24S/30S - Component Replacement
Automatic air vent
Pump
Pressure relief valve
27