Carrier 50KC04-06 Service And Maintenance Instructions

5BEARINGSThis fan system uses bearings featuring concentric split lock-ing collars. The collars are tightened through a cap screwbridging the split portion of the collar. The cap screw has aTorx T25 socket head. To tighten the locking collar: Hold thelocking collar tightly against the inner race of the bearing andtorque the cap screw to 65 to 70 in.-lb (7.4-7.9 Nm). See Fig. 7.Fig. 7 — Tightening Locking CollarMOTORWhen replacing the motor, also replace the external-tooth lockwasher (star washer) under the motor mounting base; this ispart of the motor grounding system. Ensure the teeth on thelock washer are in contact with the motor’s painted base.Tighten motor mounting bolts to 120 ± 12 in.-lb.Changing fan wheel speed by changing pulleys:The horsepower rating of the belt is primarily dictated by thepitch diameter of the smaller pulley in the drive system (typi-cally the motor pulley in these units). Do not install a replace-ment motor pulley with a smaller pitch diameter than providedon the original factory pulley. Change fan wheel speed bychanging the fan pulley (larger pitch diameter to reduce wheelspeed, smaller pitch diameter to increase wheel speed) or selecta new system (both pulleys and matching belt(s)).Before changing pulleys to increase fan wheel speed, check thefan performance at the target speed and airflow rate to deter-mine new motor loading (bhp). Use the fan performance tablesor use the Packaged Rooftop Builder software program. Con-firm that the motor in this unit is capable of operating at thenew operating condition. Fan shaft loading increases dramati-cally as wheel speed is increased.To reduce vibration, replace the motor’s adjustable pitch pulleywith a fixed pitch pulley (after the final airflow balance adjust-ment). This will reduce the amount of vibration generated bythe motor/belt-drive system.COOLINGCondenser CoilThe condenser coil is fabricated with round tube copper hairpinsand plate fins of various materials and/or coatings (see ModelNumber Format in Appendix A to identify the materials provid-ed in this unit). The coil may be one-row or composite-type two-row. Composite two-row coils are two single-row coils fabricat-ed with a single return bend end tubesheet.Condenser Coil Maintenance and Cleaning Rec-ommendationRoutine cleaning of coil surfaces is essential to maintain properoperation of the unit. Elimination of contamination and remov-al of harmful residues will greatly increase the life of the coiland extend the life of the unit. The following maintenance andcleaning procedures are recommended as part of the routinemaintenance activities to extend the life of the coil.REMOVE SURFACE LOADED FIBERSSurface loaded fibers or dirt should be removed with a vacuumcleaner. If a vacuum cleaner is not available, a soft non-metal-lic bristle brush may be used. In either case, the tool should beapplied in the direction of the fins. Coil surfaces can be easilydamaged (fin edges can be easily bent over and damage to thecoating of a protected coil) if the tool is applied across the fins.NOTE: Use of a water stream, such as a garden hose, against asurface loaded coil will drive the fibers and dirt into the coil. Thiswill make cleaning efforts more difficult. Surface loaded fibersmust be completely removed prior to using low velocity clean wa-ter rinse.PERIODIC CLEAN WATER RINSEA periodic clean water rinse is very beneficial for coils that areapplied in coastal or industrial environments. However, it isvery important that the water rinse is made with a very low ve-locity water stream to avoid damaging the fin edges. Monthlycleaning as described below is recommended.ROUTINE CLEANING OF COIL SURFACESPeriodic cleaning with Totaline ® environmentally sound coilcleaner is essential to extend the life of coils. This cleaner isavailable from Carrier Replacement Components Division aspart number P902-0301 for a one gallon container, and partnumber P902-0305 for a 5 gallon container. It is recommendedthat all coils, including standard aluminum, pre-coated, copper/copper or e-coated coils be cleaned with the Totaline environ-mentally sound coil cleaner as described below. Coil cleaningshould be part of the unit’s regularly scheduled maintenanceprocedures to ensure long life of the coil. Failure to clean thecoils may result in reduced durability in the environment.Avoid use of:• coil brighteners• acid cleaning prior to painting• high pressure washersWARNINGUNIT OPERATION AND SAFETY HAZARDFailure to follow this warning could result in personal injury,death, and/or equipment damage.This system uses Puron® refrigerant which has higherpressures than R-22 and other refrigerants. No otherrefrigerant may be used in this system. Gage set, hoses, andrecovery system must be designed to handle Puronrefrigerant. If unsure about equipment, consult the equipmentmanufacturer.