Bosch Appliances 24I RSF manual Replacement Of Parts, Component Access, Draining the Appliance

15.Replacement Of Parts

15.1IMPORTANT

Switch off the electricity and gas supplies before replacing any components. After the replacement of any components, check for gas soundness where relevant and carry out functional checks as described in Section 12 - Commissioning

15.2 COMPONENT ACCESS

To replace components it is necessary to remove one or more sections of the cabinet and cover plates within the appliance as described in Section 14.3. The facia panel may also need to be hinged down as described in Section 14.3 (c).

15.3 DRAINING THE APPLIANCE

Check that the electricity supply to the appliance is turned off. Before removing any component holding water it is important that as much water as possible is removed from the appliance.

(a)Central Heating Circuit. Turn off the central heating flow and return valves at the appliance. Open the pressure relief valve, make sure that the dust cap on the auto air vent is removed. See Fig. 30. Close the pressure relief valve when the flow has stopped. Some water will remain in the expansion vessel, pump and Gas to Water heat exchangers and extra care must be taken when removing these components.

(b)Domestic Hot Water Circuit. Turn off the mains cold supply valve at the appliance and open the lowest hot water tap. A quantity of water will remain in the Gas to Water heat exchanger, extra care must be taken when removing this component.

15.4 COMPONENT REPLACEMENT

1. Automatic Air Vent. See Figs. 30. and 32.

Remove the inner casing cover as described in Section 14.3 (b). Drain the central heating circuit as described in Section 15.3 (a). Unscrew air vent from the heat exchanger.

Fit the replacement assembly ensuring thread sealant is applied and the dust cap is removed.

Open the valves and fill and re-pressurise the system as described in Section 12.2.

2. Air Pressure Switch. See Fig. 34.

Check that the electricity supply to the appliance is turned off. Remove the cabinet front panel as described in Section 14.3 (a) and lower the facia. Section 14.3(c).

Carefully pull off the sensing tubes and the electrical connections from the switch. Remember to note their positions.

Unscrew the two screws behind the Air Pressure Switch and remove the switch from the appliance.

Fit the replacement switch in the reverse order ensuring that the electrical connections have been made to the correct terminals on the switch. Check that the sensing tubes are fitted correctly.

3.Fan. See Fig. 30.

Check that the electricity supply to the appliance is turned off. Remove the fan assembly as described in Section 14.3(e).

Fit the replacement fan in the reverse order.

4. Overheat Thermostat. See Fig. 30 and 32.

Check that the electricity supply to the appliance is turned off. Remove the inner casing cover as described in Section 14.3 (b). Carefully pull off the two wires from the thermostat head.

Undo the retaining nut on the top of the appliance and remove the retaining clip from the heat exchanger. Carefully withdraw the thermostat from the appliance.

Fit the replacement thermostat in the reverse order ensuring that some heat sink compound is between the thermostat and the heat exchanger.

5. Gas to Water Heat Exchanger. See Fig. 32.

Check that the electricity supply to the appliance is turned off. Drain the central heating circuit and domestic circuits as described in Section 15.3 (a) and (b).

Remove the inner casing cover, fan, flue hood assembly, combustion chamber front, overheat thermostat, automatic air vent and combustion chamber side insulation as described in Sections 14.3 (b, e, f and g), 15.4 (1) and 15.4 (4).

Fit the replacement heat exchanger in the reverse order ensuring that all the fibre washers are correctly fitted and a layer of heat sink compound is on the thermostat.

Open the valves and fill and re-pressurise the system as described in Section 12.2.

Fig. 32. Combustion chamber.

Heat	Auto air
exchanger	vent
Overheat
Thermostat

Hot water heat	Central heating
exchanger	heat exchanger
connections	connections

Cut-outs in	Pump bulk
combustion	head
chamber sides	connector

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