Potterton Promax SL Series Installation & Service Instructions Manual page 74

15.5 Spark and Sensing Electrodes (Fig. 51)
1. Disconnect all three leads from tabs.
Spark ­ Opaque cable
Earth ­ Green/Yellow cable
Sensing ­ White cable
2. Remove the two screws securing each of the electrodes to the combustion box door and remove the electrodes.
3. Fit the new electrodes (and new gasket, as required) and reassemble in reverse order.
15.6 Fan (Fig. 52)
WARNING: The PCB Control and Fan Assembly are 325 Vdc. Isolate at supply before access.
1. Loosen the screw holding the injector pipe into the venturi.
2. Remove the electrical connections to the fan and protection sensor on the fan.
3. Remove the wing nuts securing the fan to the base of the combustion box.
4. Lower the fan and remove.
5. If changing the fan remove the screws securing the venturi and fan protection sensor bracket, noting the positions of the injector
opening and sensor bracket, fix them to the new fan.
6. Fit the new fan and reassemble in reverse order.
The injector pipe, condensate trap and gas valve can be changed after the removal of the fan.
page 48
The removal of the fan is necessary to enable the changing of the injector pipe, condensate trap and gas valve (see section
15.6).
15.7 Injector Pipe (Fig. 53)
1. Remove the injector pipe by pulling out from the 'O' ring joint in the gas valve.
2. Fit the new injector pipe and reassemble in reverse order.