27SERVICINGClassic Slimline FF - Installation & Servicing3. Pull the HT lead connection off the printed circuit boardand pull the lead upwards through the bottom panelgrommet.4. Remove the 4 screws retaining the air box/pilot assemblyto the vertical manifold and carefully remove the assembly.1. Remove the screw retaining the front burner supportstrap to the combustion chamber. Remove the M5 pozisituated at the LH bottom rear of the burner and pull theburner downwards to disengage the retention tab.Remove the burner to a safe place for inspection andcleaning.2. Remove the control box fixing screw. Pull the box forwardand downward to disengage.To ensure the continued safe and efficient operation of theappliance, it is recommended that it is checked at regularintervals and serviced as necessary.The frequency of servicing will depend upon the installationcondition and usage, but should be carried out at leastannually. It is the law that any service work must be carried outby CORGI registered installer. In IE service work must becarried out by a Competent Person.a. Light the boiler and carry out a pre-service check, notingany operational faults. Operate the boiler for at least 20minutes. Check the gas consumption.b. Connect a suitable gas analyser to the sampling point onthe top RHS of the back panel. For correct boiler operationthe CO/CO 2 content of the flue gas should not be greaterthan 0.004 ratio. If this is the case and the gas input is atleast 90% of the nominal, then no further action need betaken. If not, proceed to paragraph c.c. Clean the main burner. Refer to Frame 51.d. Clean the heat exchanger. Refer to Frame 52.e. Clean the main and pilot injectors. Refer to Frame 53.49 SCHEDULE f. Remove any debris from inside the base of the casing.g. Check that the flue terminal is unobstructed and that the fluesystem is sealed correctly.h. If the appliance has been installed in a compartment, checkthat the ventilation areas are clear.The servicing procedures are covered more fully in Frames 50to 54 and must be carried out in sequence.WARNING.Disconnect the electrical supply and turn off gas supply.IMPORTANT. After completing the servicing or exchange ofcomponents always test for gas soundness and carry outfunctional checks as appropriate.When work is complete the casing MUST be correctly refitted,ensuring that a good seal is made.The boiler must NOT be operated if the casing is not fitted.Note.In order to carry out either servicing or replacement ofcomponents, the boiler casing must be removed. Refer toFrame 50.1. Open the controls pod door and release the 2 captivescrews at the bottom of the casing. Swing the bottom ofthe boiler casing out until the controls pod casing hascleared the controls, then unhook the casing top from thepack panel. Retain the casing in a safe place. Where theremoval of the casing is impaired by a pelmet, theinstruction in Frame 2 should be followed.2. Isolate the gas supply at the service cock fitted to the boiler.50 BOILER CASING REMOVAL51 BURNER AND AIR BOX REMOVALSERVICING