Upper front panel •Hinge down control cover to gain access to con- trol panel. •Disengage the two 'quarter turn' fasteners by turning the heads of the screws a quarter of a turn towards the centre of the boiler. •Carefully lower the panel down on its hinge until it is horizontal. •Turn both plastic catches to release upper front panel. •Remove upper front panel by pulling forward at the bottom and lifting off.

ROUTINE CLEANING AND INSPECTION

To ensure the continued efficient and safe opera-tion of the boiler it is recommended that it is checked and serviced at regular intervals. The fre- quency of servicing will depend upon the particu- lar installation conditions and usage, but in gen- eral once a year should be enough.It is the law that any servicing is carried out by acompetent person. Service Check and Preparation. •Operate boiler and check for any faults that need to be put right. •Isolate boiler from the gas and electrical supplies. •On completion check all gas carrying parts for soundness with leak detection fluid. •The maximum domestic hot water flow rate is 12 litres/minute. •Remove boiler casing as follows: Note: Important:
Diagram 28 Do not use a wire or sharp instrument on theholes. •Replace burner in reverse order to removal. Take care not to scratch or otherwisedamage painted surface of heat exchanger.
Des 047 see diagram 5. Heat exchanger Cold water inlet filter (exept SB models) •Open one or more hot water taps to drain boiler. •Undo connecting nut from cold water inlet con- nection to gain access to filter. •Remove white filter from inlet connection. from boiler taking care to retain both fibre washersand seal on gas supply for use on reassembly. •Unscrew and remove two injector bar retaining screws and separate injector bar from burner. •Examine and clean injectors as necessary. •After removal of burner, examine heat ex- changer for any blockages or build up of deposits. •Clean using soft brush or vacuum cleaner. Reassembly of parts removed for servicing •Drain down hot water circuit of boiler as follows: •Close isolating valve on cold water inlet connec- tion on fixing jig, •Replace all parts in reverse order to removal. Flue system •Check externally to make sure flue is not blocked. •Inspect flue system to make sure all fittings are secure. Operation of fan •Switch on electrical supply and turn on gas. •Switch boiler On/Off switch to 1 (On). •Light burner by opening a hot tap. •Without upper front panel in place, burner should be prevented from lighting by air flow detection system. •Refit upper front panel. •Check that fan runs when burner is lit and stops when it goes out. 18