Baxi Platinum Combi 24 HE A Installation & Servicing Instructions Manual page 47

LH Location Stud
Fig. 86
Motor Unit
Multi-pin Plug
Valve
Assembly
Fig. 87
Pressure Sensor
Control Box Cover
Fig. 89
P.C.B.
Selector
Switch
Facia
Selector Switch Knob
Fig. 90
© Baxi Heating UK Ltd 2014
Plate Heat Exchanger
Rubber Seal
Retaining Clip
Drive Pins
Temperature Control Knobs
14.0 Changing Components
14.19 Plate Heat Exchanger (Fig. 86)
1. Drain the primary circuit and remove the gas valve as
described in section 14.23.
2. While supporting the heat exchanger undo the screws
securing it to the brass manifolds.
3. Withdraw the heat exchanger upwards, taking care not to
damage any wires or controls.
Seals
4. There are four rubber seals between the manifolds and heat
exchanger which may need replacement.
5. Ease the seals out of the manifold. Replace carefully, ensuring
that when the seal is inserted into the manifold it is parallel and
pushed fully in.
6. When fitting the new heat exchanger note that the left hand
location stud is offset towards the centre more than the right
hand one.
7. Reassemble in reverse order.
14.20 Diverter Valve - Motor Unit & Assembly (Fig. 87)
1. To replace the motor unit, disconnect the multi-pin plug.
2. Pull off the retaining clip and remove the motor unit.
3. The motor unit can now be replaced, or the valve assembly
removed.
4. Drain the primary circuit and draw off any hot water once the
isolating taps are closed.
5. Undo the nuts on the tap rail under the boiler. Remove the
screws securing the valve assembly to the boiler bottom panel
and plate heat exchanger.
6. Remove the valve assembly. Examine any seals or washers,
replacing if necessary. Transfer the DHW NTC to the new valve
and reassemble in reverse order.
14.21 P.C.B. (Fig. 90)
1. Note the settings of the temperature control knobs, rotate
them fully anticlockwise and carefully pull them off the drive pins.
2. Completely undo 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. 89).
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.
14.22 Selector Switch (Fig. 90)
1. Note the setting of the selector switch knob and carefully pull
it off the facia.
2. Completely undo 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. 89).
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, ensuring that it is correctly positioned and
reassemble in reverse order. 47