29SERVICINGMexico Super FF4100 & FF4125 - Installation & Servicing56 SCHEDULEWARNING.BEFORE SERVICING always turn OFF the gas supply atthe gas service cock and switch OFF and DISCONNECTthe electrical supply to the appliance.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 ofservicing will depend upon the installation condition andusage but should be carried out at least annually .It is the law that any service work must be carried out by aCORGI registered installer. In IE servicing work must becarried out by a Competent Person.a. Light the boiler and carry out a pre-service check, notingany operational faults.b. Operate the boiler for at least 20 minutes. Check the gasconsumption.c. Connect a suitable gas analyser to the sampling point onthe flue collector. Refer to Frame 60.For correct operation the CO/CO 2 content of the flue gasshould not be greater than 0.004 ratio. If this is the caseand the gas input is within 95% of the nominal then nofurther action need be taken. If not the case, proceed tostep (d).d. Clean the main burner.e. Clean the heat exchanger.f. Clean the main injectors.g. Check that the flue terminal is unobstructed and that theflue system is sealed correctly.h. If the appliance has been installed in a compartment,check that the ventilation areas are clear. a. Light theboiler and carry out a pre-service check, noting anyoperational faults.The servicing procedures are covered more fully in Frames58 to 62 and MUST be carried out in sequence.Note.In order to carry out either servicing or replacement ofcomponents, the boiler casing must removed. Refer toFrame 57.IMPORTANT. After completing the servicing or exchange ofcomponents always test for gas soundness and carry outfunctional checks as appropriate.When the work is complete the casing MUST be correctlyrefitted and secured.The boiler must NOT be operated if the casing is not fitted.57 BOILER CASING REMOVAL1. Remove the 2 screws and lift off the lower front panel.2. Remove the 2 screws and lift off the grille assembly.3. Disconnect the electrical leads from the gas valve.4. Disconnect the in-line connector on the PCB box lead.5. Remove the thermostat phialfrom the pocket as shown.6. Remove the 2 screws securingthe control panel and pull downto release the tabs from underthe top panel.7. If the boiler is not fitted under awork top, access for fluecleaning will be improved byremoving the top panel.SERVICING