Carrier 50SZ Series Installation, Start-up And Service Instructions Manual

Also see for 50SZ Series: Manual Product data

Contents

when the outdoor temperature is below 40° F (unless accessorylow-ambient kit is installed). Do not rapid-cycle the compressor.Allow 5 minutes between “on” cycles to prevent compressordamage.CHECKING COOLING AND HEATINGCONTROL OPERATIONStart and check the unit for proper control operation as follows:1. Place room thermostat SYSTEM switch in OFF position.Observe that blower motor starts when FAN switch is placedin ON position and shuts down within 60 sec. when FANswitch is placed in AUTO position.2. Place SYSTEM switch in COOL position and FAN switch inAUTO position. Set control below room temperature. Observethat cooling cycle shuts down when control setting is satisfied.3. Place system switch in HEAT position. Set control aboveroom temperature. Observe that compressor, outdoor fan, andindoor blower motor starts. Observe that heating cycle shutsdown when control setting is satisfied.4. When using an automatic changeover room thermostat, placeboth SYSTEM and FAN switches in AUTO positions. Ob-serve that unit operates in Cooling mode when temperaturecontrol is set to “call for Cooling” (below room temperature),and unit operates in Heating mode when temperature controlis set to “call for Heating” (above room temperature).CHECKING AND ADJUSTING REFRIGERANT CHARGEThe refrigerant system is fully charged with R-22 refrigerant andis tested and factory sealed. Allow system to operate a minimumof 15 minutes before checking or adjusting charge.NOTE: Adjustment of the refrigerant charge is not requiredunless the unit is suspected of not having the proper R-22 charge.The charging label and the tables shown refer to system tempera-tures and pressures in cooling mode only. A refrigerant charginglabel is attached to the outside of the service access door. If chargelevel is suspect in Heating mode, reclaim all refrigerant and chargeto nameplate amount. (This information may be obtained from thephysical data table also.)IMPORTANT: When evaluating the refrigerant charge, an indi-cated adjustment to the specified factory charge must always bevery minimal. If a substantial adjustment is indicated, an abnormalcondition exists somewhere in the cooling system, such as insuf-ficient airflow across either coil or both coils.REFRIGERANT CHARGEThe amount of refrigerant charge is listed on the unit nameplateand/or the physical data table. Refer to the Refrigeration ServiceTechniques Manual, Refrigerants Section.NO CHARGECheck for leak. Use standard evacuating techniques. After evacu-ating system to 500 microns, weigh in the specified amount ofrefrigerant (refer to system data plate).LOW CHARGE COOLINGUse Cooling Charging Charts (See Table 8). Vary refrigerant untilthe conditions of the chart are met. Note that charging charts aredifferent from type normally used. Charts are based on chargingthe units to correct superheat for the various operating conditions.Fig. 13—Control ConnectionsC99056YCW2EGROTHERMOSTATAND SUBBASE UNIT CONTROL POWERSPLICE BOXBRNWHTYELGRNREDORNFig. 14—Line Power ConnectionsA05141GROUND SCREW(IN SPLICE BOX)YELBLKGROUNDLEADSINGLE-PHASECONNECTIONSTO DISCONNECTPER NECLEGENDNEC – National Electrical CodeField WiringSplice ConnectionsNOTE: Use copper wire only.L1L2Fig. 15—Control Wiring PlateC9907024 V Circuit Breaker24 Volt CompartmentFig. 16—Fan Blade ClearanceC99009FAN GRILLEMOTOR1/8" MAX BETWEENMOTOR AND FAN HUB MOTOR SHAFT1/2˝12