Potterton Combi 80, Installation & Service Instructions Manual

Page: 35 / 47

Replacement of Parts - Page 35
5.24 Expansion Vessel D.H.W.
- Fig. 23
Isolate the electrical supply prior to this operation.
1. Remove the white front case and base panel.
See 4.1 & 4.2in ’Routine Maintenance’.
2. Lower the control panel assembly by undoing the
securing screw at the top right hand side of the control
panel. Close the isolating valve on the cold water inlet
and open the lowest hot water tap. Remove the drain
screw on the isolating valve to completely drain the
appliance. Replace drain screw in isolator valve.
3. Remove the access panel to the left of the transformer.
Temporarily remove the transformer - See 5.28.
Note : It is not necessary to fully remove the top right
hand screw.
4. Release the vessel by unscrewing it from the inlet
manifold.
5. Carefully withdraw the vessel through the access hole.
Refit new component.
6. Re-assemble in reverse order, using a new sealing
washer. Open the isolating valve, and check for leaks.
5.25 Heat Exchanger - Fig. 14
1. Perform 4.1 to 4.6 & 4.8 in ‘Routine Maintenance’.
Remove the combustion chamber insulation by
removing each side panel retaining screw and pulling
the complete side panel /insulation assembly forwards.
The rear insulation can remain in situ.
2. Drain the appliance as described on Page 26. Undo the
heat exchanger connection to the auto air vent pipe.
3. Disconnect the electrical connections from the C.H.
overheat thermostat. The control box should be
protected from water spillage.
4. Release the four spring clips retaining the heat
exchanger tails by pulling the clip forwards and towards
the centre of the appliance and ease the heat exchanger
up, out of the housings.
5. The heat exchanger waterways can now be descaled or
a replacement heat exchanger can be fitted, in which
case the overheat thermostat must be transferred to the
new heat exchanger.
6. Re-assemble in reverse order. Use a soap solution to
lubricate the new ‘O’ rings when fitting the new heat
exchanger, also, ensure the heat exchanger is pushed
fully down. Re-charge the system as described in
Section 1.8 and check the joints for leaks.