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

Also see for 50SZ Series: Manual Product data

Contents

INSTALLATION REQUIREMENTSFailure to follow these precautions could result in damage tothe unit being installed:1. Make all electrical connections in accordance with NECANSI/NFPA (latest edition) and local electrical codesgoverning such wiring. In Canada, all electrical connec-tions must be in accordance with CSA standard C22.1Canadian Electrical Code Part 1 and applicable localcodes. Refer to unit wiring diagram.2. Use only copper conductor for connections betweenfield-supplied electrical disconnect switch and unit. DONOT USE ALUMINUM WIRE.3. Be sure that high-voltage power to unit is within operatingvoltage range indicated on unit rating plate. Consult localpower company for correction of improper voltage.4. Insulate low-voltage wires for highest voltage containedwithin conduit when low-voltage control wires are in sameconduit as high-voltage wires.5. Do not damage internal components when drilling throughany panel to mount electrical hardware, conduit, etc.HIGH-VOLTAGE CONNECTIONSThe unit must have a separate electrical service with a field-supplied, waterproof disconnect switch mounted at, or within sightfrom the unit. Refer to the unit rating plate, NEC and local codesfor maximum fuse/circuit breaker size and minimum circuit amps(ampacity) for wire sizing (See Table 3 for electrical data).The field-supplied disconnect may be mounted on the unit over thehigh-voltage inlet hole (See Fig. 2 and 3).If the unit has an electric heater, a second disconnect may berequired. Consult the Installation, Start-Up, and Service Instruc-tions provided with the accessory for electrical service connec-tions.Operation of unit on improper line voltage constitutes abuse andmay cause unit damage that could affect warranty.ROUTING POWER LEADS INTO UNITUse only copper wire between disconnect and unit. The high-voltage leads should be in a conduit until they enter the duct panel;conduit termination at the duct panel must be watertight. Run thehigh-voltage leads through the power entry knockout on the powerentry side panel. See Fig. 2 and 3 for location and size. When theleads are inside the unit, run leads up the high-voltage raceway tothe line wiring splice box (See Fig. 13). For single-phase units,connect leads to the black and yellow wires (See Fig. 14).CONNECTING GROUND LEAD TO GROUND SCREWConnect the ground lead to the chassis using the ground screw inthe wiring splice box (See Fig. 14).ROUTING CONTROL POWER WIRES (24-V)Form a drip-loop with the thermostat leads before routing theminto the unit. Route the thermostat leads through grommeted,low-voltage hole provided in unit into unit control power splicebox (See Fig. 2 and 3). Connect thermostat leads to unit controlpower leads as shown in Fig. 13.The unit transformer supplies 24-v power for complete systemincluding accessory electrical heater. An automatic-reset circuitbreaker (See Fig. 15) is provided in the 24-v circuit; see the cautionlabel on the transformer. Transformer is factory wired for 230-voperation. If supply voltage is 208-v, rewire transformer primaryas described in Special Procedures for 208-v Operation section.SPECIAL PROCEDURES FOR 208-V OPERATION1. Disconnect the yellow primary lead from the transformer. Seeunit wiring label (See Fig. 12).2. Connect the yellow primary lead to the transformer terminallabeled 200-v.Indoor blower-motor speeds may need to be changed for 208-voperation. Refer to indoor airflow and airflow adjustments section.PRE-START-UPFIRE, EXPLOSION, ELECTRICAL SHOCK HAZARDFailure to observe the following warnings could result inserious personal injury or death:1. Follow recognized safety practices and wear protectivegoggles when checking or servicing refrigerant system.2. Do not operate compressor or provide any electric power tounit unless compressor terminal cover is in place andsecured.3. Do not remove compressor terminal cover until all electri-cal sources are disconnected and tagged.4. Relieve and recover all refrigerant from system beforetouching or disturbing anything inside terminal box ifrefrigerant leak is suspected around compressor terminals.5. Never attempt to repair soldered connection while refrig-erant system is under pressure.6. Do not use torch to remove any component. Systemcontains oil and refrigerant under pressure.To remove a component, wear protective goggles andproceed as follows:a. Shut off electrical power to unit and install lockout tag.b. Relieve and reclaim all refrigerant from system usingboth high- and low-pressure ports.c. Cut component connecting tubing with tubing cutter andremove component from unit.d. Carefully unsweat remaining tubing stubs when neces-sary. Oil can ignite when exposed to torch flame.Use the Start-Up Checklist supplied at the end of this book andproceed as follows to inspect and prepare the unit for initialstart-up:1. Remove access panel.2. Read and follow instructions on all DANGER, WARNING,CAUTION, and INFORMATION labels attached to, orshipped with, unit.Transformer contains a manual reset overcurrent protector.It will not automatically reset. Disconnect power and installlockout tag prior to servicing. This compartment must beclosed except when servicing.3. Make the following inspections:a. Inspect for shipping and handling damages such as brokenlines, loose parts, disconnected wires, etc.b. Inspect for oil at all refrigerant tubing connections and onunit base. Detecting oil generally indicates a refrigerantleak. Leak-test all refrigerant tubing connections usingelectronic leak detector, or liquid-soap solution. If a refrig-erant leak is detected, see following Check for RefrigerantLeaks section.c. Inspect all field and factory-wiring connections. Be surethat connections are completed and tight.d. Ensure wires do not touch refrigerant tubing or sharpsheetmetal edges.9