Carrier 48/50PG C03-14 Operation And Service Manual

Contents

87Condenser-Fan Adjustment (Fig. 55)1. Shut off unit power supply.2. Remove condenser-fan assembly (grille, motor, motorcover, and fan) and loosen fan hub setscrews.3. Adjust fan height as shown in Fig. 55.4. Tighten setscrews and replace condenser-fan assembly.5. Turn on power to unit.C09292Fig. 55 − Condenser−Fan AdjustmentNOVATION Heat Exchanger Condenser Serviceand ReplacementThe condenser coil in this unit is a NOVATION heat exchangersurface. The NOVATION heat exchanger is an all−aluminumconstruction with fins over a single−depth crosstube. Thecrosstubes have multiple small passages through which therefrigerant passes from header to header on each end. (See Fig. 56.)The all−aluminum construction provides increased resistance tocorrosion over aluminum fins on copper tubes in normal and mildmarine applications.EQUIPMENT DAMAGE HAZARDFailure to follow this caution may result in damage toequipment.Refer to product data manual for coil usage in coastal orindustrial applications.CAUTION!TUBESFINSMICROCHANNELSMANIFOLDa30-4457C07273Fig. 56 − NOVATION Heat Exchanger CoilsRepairing Tube LeaksRCD offers service repair kits for repairing tube leaks in thecrosstubes. These kits include approved braze materials andinstructions specific to the aluminum NOVATION heat exchangercoil.EQUIPMENT DAMAGE HAZARDFailure to follow this caution may result in damage toequipment.Use of other than approved repair procedures may affect thepressure rating or the corrosion resistance of the NOVATIONheat exchanger condenser coil.CAUTION!Replacing the NOVATION Heat Exchanger CoilThe service replacement coil is preformed and is equipped withtransition joints with copper stub tubes. When brazing theconnection joints to the unit tubing, use a wet cloth around thealuminum tube at the transition joint. Avoid applying torch flamedirectly onto the aluminum tubing.Verify Sensor PerformanceVerify that thermistor, transducer, and switch inputs are readingcorrectly. These values can be accessed through the ScrollingMarquee display in the Temperatures, Pressures, and Inputs menus.Some values will depend on configuration choices. Refer to theControl Set Up Checklist completed for the specific unitinstallation and to the configuration tables in Appendix A.Economizer Operation During Power FailureDampers have a spring return. In event of power failure, damperswill return to fully closed position until power is restored. Do notmanually operate damper motor.EvacuationProper evacuation of the system will remove noncondensables andensure a tight, dry system before charging. Evacuate from bothhigh and low side ports. Never use the system compressor as avacuum pump. Refrigerant tubes and indoor coil should beevacuated to 500 microns. Always break a vacuum with drynitrogen. The two possible methods are the deep vacuum methodand the triple evacuation method.Deep Vacuum MethodThe deep vacuum method requires a vacuum pump capable ofpulling a minimum vacuum of 500 microns and a vacuum gaugecapable of accurately measuring this vacuum depth. The deepvacuum method is the most positive way of assuring a system isfree of air and liquid water. (See Fig. 57.)LEAK INSYSTEMVACUUM TIGHTTOO WETTIGHTDRY SYSTEM0 1 2 3 4 5 6 7MINUTES500045004000350030002500200015001000500MICRONSC06264Fig. 57 − Deep Vacuum Graph48/50PG and PM