28SERVICINGClassic Slimline FF - Installation & Servicing9. Remove all loose deposits from the heat exchanger,particularly between the fins, using a suitable brush.10. Reassemble in reverse order, ensuring the fan leadsand 3 sensing tubes are reconnected.1. Remove the 2 silicon rubber tubes from the fan sensingpoints.2. Disconnect the fan leads.3a. Rear flueSlacken the M4 screw securing the flue connector to thefan. Disconnect the connector from the fan and slideinto the flue.3b. Side flueSlacken off two M4 screws securing the flue elbow andflue connector. Disconnect the flue connector from theelbow and slide into the flue. Remove the flue elbow.4. Disconnect the silicon rubber tube from the rear of thecollector hood.5. Slacken the two M5 nuts on the front tie rods, releasingthe tie rods from the combustion chamber.6. Remove the M5 central fixing screw at the rear of thecollector hood and remove collector hood/fan assembly.7. Check that the fan impeller runs freely. Remove anydebris from the impeller with a soft brush.8. Remove the flue baffles.52 CLEANING THE FAN ASSEMBLY / THE FLUEWAYS53 CLEANING THE BURNER AND PILOT ASSEMBLY1. Brush off any deposits that may have fallen on to theburner head (ensuring the flame ports are unobstructed)and remove any debris that may have collected.Note.Brushes with metallic bristles must not be used.2. Remove the main burner injector and ensure there is noblockage or damage. Clean or renew as necessary.3. Refit the injector, using an approved jointing compoundsparingly.4. Inspect the pilot burner and ignition / detection electrode.Ensure that they are clean and in good condition.Check that:a. The pilot burner injector is not blocked or damaged.Refer to Frame 60 for removal details.b. The pilot burner is clean and unobstructed.c. The ignition / detection electrode is clean andundamaged.d. The ignition / detection lead is in good condition.e. The spark gap is correct (refer to Frame 60). Clean orrenew as necessary.Note.The pilot shield is located around the pilotassembly bracket and is located by the electroderetaining nut.Reassemble the boiler in the following order.1. Refit the flue baffles.2. Inspect the collector hood rope gasket and replace, ifnecessary, ensuring that the self adhesive rope is fittedcentrally on to the lip of the collector hood / fanassembly. The boiler efficiency will be adverselyaffected if incorrectly fitted. Refit the collector hood andretain with the 2 front tie rods and the rear central fixingscrew. Tighten the nuts and screw. Ensure that thesealing gasket is compressed. Refit the pressure pipe.3. Refit the positive pressure tubes on the top of the fanhousing. Reconnect the electrical leads.4. Refit the air box assembly and burner. Ensure that theburner front fixing is refitted.5. Reconnect the gas supply and the electrical wiring. Referto Frames 36 & 38.6. Check the sightglass in the boiler casing. Clean or renewas necessary. Refer to Frame 57.7. Check for gas soundness. Check the gas service cockand pressure test point.8. Refit the boiler casing (Refer to Frame 46, item 20). Notethat it is not necessary to disturb the controls casing pod.9. Close the controls pod door.54 REASSEMBLYSERVICING