24
Alpha SolarSmart 100 - Component Replacement
8.6 CYLINDER TEMPERATURE SENSORS
Both sensors are the same.
Remove the cylinder case as described in Section 8.1.
Remove the split pin retaining the sensor in the pocket (see Fig. 27) and withdraw the sensor. Disconnect the sensor leads
from the control unit.
Reassemble in reverse order, ensuring the sensor is retained with the split pin.
8.7 PRESSURE RELIEF VALVE
The pressure relief valve is supplied as an assembly - the inlet safety manifold assembly (see Fig. 27).
Loosen and remove the four fittings from the assembly. Lift out the assembly taking care not to lose the mains inlet mesh
filter.
Reassemble in reverse order using new seals. Ensure the mesh filter is in position.
8.8 CONTROL UNIT
Remove the cylinder case as described in Section 8.1.
Remove the two fixing screws and lift off the terminal block cover (see Fig. 27). Remove all terminal connections from the
control unit. Remove the two screws securing the control unit (see Fig. 27) and remove the unit.
Reassemble in reverse order.
8.9 DBU PUMP
Note:
Care must be taken when carrying out repairs to the DBU as it reaches very high temperatures and can emit steam
from connections when being removed.
Isolate the mains electric supply and remove the front case of the drain back unit by simply pulling it forwards.
Place a bucket under the drain plug at the bottom of the unit and using a suitable spanner, unscrew the plug while holding
the plug housing with another spanner to prevent damaging the pipe. Expect about 8 litres.
Remove the two screws securing the pump retaining bracket (see Fig. 28) and remove the bracket.
Undo the two pump unions (see Fig. 28) and withdraw the pump.
Inside the main cylinder case - remove the two fixing screws and lift off the terminal block cover (see Fig. 27) and disconnect
the pump leads from terminals 12, 13 and
. Release the cable clamp and withdraw the lead. If the lead has been
extended, disconnect it from the relevant junction box.
Reassemble in reverse order using new pump washers. Refer to Section 4.5, paragraph 3 if required when connecting the
pump lead.
Refer to Section 5.2 to refill the drain back unit.
Fig. 28
Pump unions
Drain point
Retaining bracket fixing screws
Heat exchanger
Connection and locknut
Connection and locknut
Cylinder bottom connection
Heat exchanger connections
(4 off)
