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manual abstract
Slide the expansion vessel and insulation out of the retaining clips. 7. Reassemble in reverse order using new sealing washers. Fully recommission the appliance and system. 12.17 Condensate Trap (Fig. 63) 1. Disconnect the two sensing wires from the trap connections. 2. Squeeze together the wire spring clip to release and ease the inlet pipe from the trap spigot. 3. Undo the nut securing the condensate drain pipe to the trap. Disconnect the pipe and sealing washer. 4. From underneath the boiler remove the screws securing the trap bracket. 5. Remove the trap and bracket from the boiler. Undo the locknut securing the trap to the bracket. 6. Reassemble in reverse order. Pressure Gauge Timer Cover Pressure Gauge Capillary Gauge Retaining Bracket Expansion Vessel Retaining Clip Appliance Upper Cross Member Vessel Spigots Boiler Chassis Lock Nut Fig. 60 Fig. 61 Fig. 62 Pipe ‘B’ Pipe ‘A’ Sensing Wires Inlet Pipe Condensate Trap Wire Spring Clip Bracket Condensate Drain Pipe Fig. 63 12.0 Changing Components 37 12.18 Pressure Relief Valve (Fig. 64) 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. 66) 1. Note the settings of the temperature control knobs. Rotate the knobs 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. 65). 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 (Fig. 66) 1. Turn the selector switch knob to the off position 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. 65). 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. 64 Fig. 65 Fig. 66 Drive Pins 12.0 Changing Components 38 12.21 Plate Heat Exchanger (Fig. 67) 1. Drain the primary circuit. 2. While supporting the heat exchanger undo the screws securing it to the brass manifolds. 3. Withdraw the heat exchanger upwards and to the left of the gas valve, taking care not to damage any wires or controls. Seals 4. There are four rubber seals between the manifolds and heat exchanger which may require replacement. 5. Ease the seals out of the manifolds. Replace carefully, ensuring that the seal is inserted into the manifold 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. 12.22 Diverter Valve Assembly (Figs. 68 & 69) The diverter valve assembly comprises of a central heating pressure differential valve and a domestic hot water pressure differential valve. These are connected to a manifold which is joined to the plate heat exchanger. DHW Pressure Differential Valve Diaphragm (Figs. 68 & 69) 1. Turn off the mains water inlet tap and drain the domestic hot water by turning on a hot tap. 2. Prise off the spring clip retaining the microswitch. Pull the switch away. 3. Undo the sensing pipe nut from the valve and slacken the nut at the inlet manifold. Ease the pipe away from the valve. 4. Undo the screws securing the differential valve cover. 5. Carefully draw off the cover and remove the diaphragm, noting the orientation. 6. Fit the new diaphragm and reassemble in reverse order. Plate Heat Exchanger Rubber Seal Rubber Seal DHW Pressure Differential Valve Microswitch Sensing Pipe Thrust Plate Pushrod Diaphragm Spring Diaphragm Fig. 67 Fig. 68 Fig. 69 Spring Clip DHW Pressure Differential Valve Cover Offset Stud 12.0 Changing Components 39 12.22 Diverter Valve Assembly (Cont) CH Pressure Differential Valve Diaphragm (Fig. 70) 1. Isolate the boiler from the central heating flow and return pipes and drain the boiler primary circuit. 2. Prise off the spring clip retaining the microswitch. Pull the switch away. 3. Undo the screws securing the different...