Potterton Performa 28i, Installation And Servicing Instructions, Page: 35 / 48

12.0 Changing Components
35
12.18 Pressure Relief Valve (Fig. 61)
1. Drain the primary circuit.
2. Disconnect the discharge pipe from the valve.
Using a suitable hexagon key undo the grub
screw sufficiently to release the valve.
3. Note the orientation of the valve, rotate it and
withdraw it from the manifold.
4. Fit the new valve and ‘O’ ring seal and set to
the previously noted orientation. Reassemble in
reverse order.
12.19 P.C.B. (Fig. 63)
1. Note the settings of the temperature control
knobs. Rotate the knobs fully anticlockwise and
carefully pull them off the drive pins.
2. Remove the screws securing the control box
cover and release the cover retaining barbs from
their slots. Disengage the rear of the cover from
the control box hinge pin (Fig. 62).
3. Note the position of all plugs and wires on the
P.C.B. and disconnect them.
4. Undo the securing screws and remove the
P.C.B. Transfer the control knob drive pins to the
new P.C.B. and turn them fully anticlockwise.
5. Reassemble in reverse order, ensuring that the
temperature controllers are reset to their previous
positions.
12.20 Selector Switch
1. Turn the selector switch knob to the off position
and carefully pull it off the facia.
2. Remove the screws securing the control box
cover and release the cover retaining barbs from
their slots. Disengage the rear of the cover from
the control box hinge pin.
3. Note the position of the electrical connections
and the orientation of the switch. Remove the
electrical connections.
4. Remove the screws securing the switch to the
facia panel.
5. Fit the new switch and reassemble in reverse
order. Turn the knob to the required setting.
Pressure Relief Valve
Grub Screw
‘O’ ring seal
Discharge Pipe
Control Box Cover
P.C.B.
Selector
Switch
Facia
Selector Switch Knob
Temperature Control Knobs
Fig. 61
Fig. 62
Fig. 63
Drive Pins