Carrier FA4ANF Service Manual

hot water and detergent. Be careful not to disturb balance weights(clips) on blower wheel vanes. Do not drop or bend wheel asbalance will be affected.FG3A SERVICE AND TROUBLESHOOTINGStep 1—ServiceMOTORBall bearing oilers are provided on blower motor. Use electricmotor oil or SAE 10 or 20 nondetergent oil. Check motor mountbracket and base bolts. Tighten as required.BLOWERCheck ball bearings for wear. Ball bearings are self-aligning andgrease packed. Replace as required. Check thrust collars for endplay and alignment of wheel. Check blades for accumulation ofdirt. Clean as required. Check mounting brackets, base bolts, andisolation material.See Fig. 37 for diagram of internal wiring for blower coilassembly. Control box (standard 4-in. junction box) is mounted onrefrigerant connection side of unit. All leads pass through strainrelief where they enter control box. Wiring inside cabinet islocated so it does not come in contact with moving parts or sharpedges.PULLEY AND BELTSCheck belt tension and pulley alignment. (See Fig. 38.) Belttension is adjusted by motor tailpiece bolt. A deflection of about3/4 in. to 1 in. per foot of span should be obtained by pressing beltfirmly. Lock adjusting bolt in position after adjustment is made.Align pulley grooves by locating motor pulley on motor shaft or bymoving entire motor along motor mounting bracket. Adjust blowerspeed by loosening setscrew in outer (moveable) pulley face andturning this face (half or full turns) so that adjusting setscrew ispositioned precisely over the flat on pulley hub. Speed is reducedby adjusting pulley faces so they are further apart; speed isincreased with faces closer together. Check pulley setscrews andbolts.CLEANING OR REPLACING REFRIGERANTFLOW-CONTROL DEVICERefer to Fig. 36 and instructions given in FD3A Service andTroubleshooting section above.Step 2—MaintenanceDisconnect electrical power to all circuits before servicingunit. Failure to do so may result in personal injury fromelectrical shock or moving parts.As with any mechanical equipment, personal injury can resultfrom sharp metal edges. Be careful when removing parts.RETURN-AIR FILTERTo clean or replace air filter, remove screws and filter access door.Slide out filter. For washable type filters, clean with hot soapywater. Rinse clean and let dry.New filters are available from a local distributor. Place filter in slotwith filter arrow facing direction of airflow. Replace filter accessdoors with screws previously removed.Never operate unit without a filter or with filter access doorremoved. Damage to blower motor may result.COIL, DRAIN PAN, AND CONDENSATE DRAINDisconnect electrical power before removing any accesspanels or electrical shock may result.The coil is easily cleaned when dry. To check or clean coil, removecoil access panel. If coil is coated with dirt or lint, vacuum with asoft brush attachment.Be careful not to bend fins. If coil is coated with oil or grease, itmay be cleaned with mild detergent and water solution. Rinse coilwith clean water. Be careful not to splash water on insulation orfilter.Check drain pan and condensate drain at same time cooling coil ischecked. Clean drain pan and condensate drain by removing anyforeign matter from pan. Check for rust and holes. Flush pan anddrain tube with clear water. If drain is restricted, clean withhigh-pressure water. If this does not work, use a plumber’s snakeor similar probe device. Repitch drain pan to promote properdrainage.FA4A, FB4A, FC4B, AND FX4A SMART HEATCIRCUIT BOARD FUNCTION AND TROUBLESHOOTINGStep 1—PCB Component Layout, Description,and FunctionNOTE: All voltages are AC unless otherwise specified.1. The low-voltage terminal board is used to connect indoorthermostat to low, 24-v side of transformer and to serve as ajunction between indoor thermostat and outdoor section.a. R terminal is used to connect secondary side of transformerto thermostat and outdoor unit. R is fused.b. C terminal is used to connect transformer secondarycommon for thermostat and outdoor unit.c. Y terminal provides input signal from thermostat signalingheat pump operation.Fig. 37—Wiring SchematicA91151BLOWERMOTORGROUNDUTILITYBOXGROUNDLEADLINEFig. 38—Checking Pulley Alignment and TightnessA911501′3⁄4″BELT ADJUSTMENTPULLEY ALIGNMENTMUST BEPARALLELFOR PROPERALIGNMENT46