Technical data

26
8.22 MAIN HEAT EXCHANGER - Refer to Fig. 23
1. Drain the boiler heating circuit as described in section 8.2.
2. Remove the four screws securing the combustion chamber front cover and remove the cover.
3. Remove the fan assembly as described in section 8.7.
4. Remove the two screws securing the flue hood and lift out the flue hood.
5. Remove the two screws securing the heat exchanger and remove by pulling it towards the front, being careful not to
damage the combustion chamber insulation.
6. Fit a new heat exchanger, using new 'O' rings. Lubricating the 'O' rings with a soap solution will aid assembly. Ensure the
heat exchanger is correctly located between the combustion chamber insulation sides.
7. Replace the two screws securing the heat exchanger.
8. Re-assemble in reverse order.
Note: Connect the fan wiring, blue to terminal 1 and brown to terminal 2. Ensure the pressure tubes are connected
correctly - refer to Fig. 23.
9. Refill and pressurise the system. (Refer to Commissioning, section 5.1).
8.23 COMBUSTION CHAMBER INSULATION
1. Gain access as described in section 8.1.
2. Remove the four screws securing the combustion chamber front cover and remove the cover.
3. Slide out the insulation front panel from the front cover.
4. To replace the rear and side panels, remove the heat exchanger as described in section 8.22 and slide out the insulation panels.
5. Fit a new panel and re-assemble in reverse order.
Note: Connect the fan wiring, blue to terminal 1 and brown to terminal 2. Ensure the pressure tubes are connected
correctly - refer to Fig. 23.
6. Refill and pressurise the system. (Refer to Commissioning, section 5.1).
8.24 PRESSURE GAUGE
1. Gain access as described in section 8.1.
2. Drain the boiler heating circuit as described in section 8.2.
3. Remove the nut securing the pressure gauge sensor to the return/filter housing and withdraw the sensor.
4. Remove two screws securing the gauge to the control panel and withdraw.
5. Fit the new gauge using a new washer on the diverter valve connection if necessary.
6. Refill and pressurise the system. (Refer to Commissioning, section 5.1).
8.25 TEMPERATURE SENSORS - Fig. 29
The temperature sensors fitted to the hot water storage, primary return and primary flow are all the same. Refer to Fig. 2 for
their location.
1. Gain access as described in section 8.1.
2. Disconnect the wiring and unscrew the sensor. Re-assemble in reverse order with a new sensor.
8.26 AUTOMATIC AIR VENT - Fig. 29
1. Drain the boiler heating circuit as described in section 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).
8.27 PUMP - Fig. 29
Drain the boiler heating circuit as described in section 8.2.
Pump Head
1. Remove the four socket head screws securing the pump head to the body. Withdraw the head, remove the wiring cover
and disconnect the wiring.
2. Connect the wiring to the new head as follows:-
Brown to L, Blue to N, Green/yellow to .
Ensure the pump is set to maximum (3) and re-assemble in reverse order.
3. Refill and pressurise the system. (Refer to Commissioning, section 5.1).
Alpha 500E - Component Replacement