Potterton Combi 80, Installation & Service Instructions Manual

Page: 24 / 47

Servicing & Routine Maintenance - Page 24
4.8 Remove the Burner
- Fig. 15
1. Disconnect the two leads to the electrodes. (Do not pull
on the cable).
2. Undo the hexagonal union nut under the burner, taking
care not to lose the seal *. Carefully pull the burner
forward approximately 3 mm to disengage the rear
burner supports, then lift the rear of the burner to an
angle greater than 45°. Continue to roll the burner out of
the appliance.
3. Remove the burner injectors separately to examine their
status, clean or renew as necessary.
* If, during removal of the burner the burner sealing
washer becomes damaged, the appliance is supplied as
standard with two spare sealing washers. They are in a
polythene bag located on the inside face of the base
panel. Further washers can be purchased from
Potterton, Part No.13-18693. If the boiler has been
operating, care must be taken to avoid contact with any
hot pipework on the underside of the appliance, during
inspection and cleaning.
4.9 Gas Pressures - Adjustment
See Section 3 'Commissioning'.
4.10 The Central Heating Sealed System
1. Check that the pressure in the system is being
maintained. The red indicator will have been set (outer
case of gauge turns clockwise) to show the system
pressure. If the black indicator shows a lower pressure
than the red indicator, the system has lost pressure and
should be re-pressurised. The correct procedures are
shown in the installation section. See
'permissible methods of filling’ Page 11.
4.11 Other Components
No further servicing is required on any other appliance
components.
It may occasionally be necessary to replenish the pre-
charge in the expansion vessel. This can be readily
achieved by use of a portable air pump.
Note: The water side of either expansion vessel must be
depressurised prior to re-pressurising the air side.
Access can be made to the charging point on the vessels, as
follows:
1. Central heating expansion vessel - access is made to
the vessel charging point from above on the right hand
side of the appliance. Re-pressurise to a minimum of 1
bar (14.5 lb/in) or marginally greater than the designed
system pressure at the appliance when cold, which ever
is higher.
2. Domestic hot water expansion vessel - access is made
by lowering the controls panel and removing the access
cover on the rear panel, also temporarily remove the
transformer. The vessel charge point can now be
connected. Re-pressurise the vessel to 3.5 bar (51 p.s.i)
or higher if mains water pressure is higher.
Note: If the portable pump can not easily be connected,
the vessel can be removed and re-pressurised off the
appliance.