Carrier 69NT40-511-1 Operating And Service Manual

Also see for 69NT40-511-1: Operation and service

Contents

6-18T-268-07WARNINGWith power OFF discharge the capacitorand disconnect the circuit wiring.c. Checking the capacitorIf the capacitor is suspected of malfunction, you maychoose to simply replace it. Direct replacement requiresa capacitor of the same value. Two methods forchecking capacitor function are:1. Volt-ohmmeter set on RX 10,000 ohms. Connectohmmeter leads across the capacitor terminals andobserve the meter needle. If the capacitor is good, theneedle will make a rapid swing toward zero resistanceand then gradually swing back toward a very highresistance reading.If the capacitor has failed open, the ohmmeter needlewill not move when the meter probes touch theterminals. If the capacitor is shorted, the needle willswing to zero resistance position and stay there.2. Capacitor analyzerThe function of the analyzer is to read the microfaradvalue of a capacitor and to detect insulation breakdownunder load conditions. The important advantages of aanalyzer are its ability to locate capacitors that havefailed to hold their microfarad ratings, or those that arebreaking down internally during operation. It is alsouseful in identifying capacitors when their microfaradrating marks have become unreadable.6.17 CONDENSER COILThe condenser consists of a series of parallel coppertubes expanded into copper fins. The condenser coilmust be cleaned with fresh water or steam so the air flowis not restricted. Fan rotation is counterclockwise whenviewed from shaft end of motor.WARNINGDo not open the condenser fan grille beforeturning power OFF and disconnectingpower plug.To Replace Condenser Coil:a. Remove the refrigerant charge per section 6.3.b. Remove the condenser coil guard.c. Unsolder discharge line and remove the line to thereceiver or water-cooled condenser (if soequipped).d. Remove coil mounting hardware and remove thecoil.e. Install replacement coil and solder connections.f. Leak-check the coil per section 6.4. Evacuate theunit per section 6.5, then charge the unit withrefrigerant per section 6.6.1.6.18 CONDENSER FAN AND MOTOR ASSEMBLYWARNINGDo not open condenser fan grille beforeturning power OFF and disconnectingpower plug.The condenser fan rotates counter-clockwise (viewedfrom front of unit), pulls air through the the condensercoil, and discharges horizontally through the front of theunit. To replace motor assembly:a. Open condenser fan screen guard.b. Loosen two square head set screws on fan. (Threadsealer has been applied to set screws at installation.)Disconnect wiring from motor junction box.CAUTIONTake necessary steps (place plywood overcoil or use sling on motor) to prevent motorfrom falling into condenser coil.c. Remove motor mounting hardware and replace themotor. It is recommended that new locknuts be usedwhen replacing motor. Connect wiring per wiringdiagram.d. Install fan loosely on motor shaft (hub side in). DONOT USE FORCE. If necessary, tap the hub only,not the hub nuts or bolts. Install venturi. Apply“Loctite H” to fan set screws. Adjust fan withinventuri so that the outer edge of the fan projects 3.2to 6.4 mm (3/16” ¦1/16”) back from edge of theventuri. Spin fan by hand to check clearance.e. Close and secure condenser fan screen guard.f. Apply power to unit and check fan rotation. If fanmotor rotates backward, reverse wire numbers 5and 8.6.19 PARTLOW RECORDING THERMOMETERNOTEThe Controller/DataCORDER return air probeis located adjacent to the Partlow bulb, and canbe used to calibrate the chart recorder.a. Instruments for Checking Bulb TemperatureThe recording thermometer may be optionally equippedwith one or two Simpson accessories (#344 units), eachconsisting of a thermistor probe and receptacle