GLOVES
SAFETY GLASSES
REGULAR AND PHILLIPS HEAD SCREW DRIVERS
SMALL ADJUSTABLE WRENCH
ALLEN WRENCH SET (EXTRA LENGTH)
3/8-IN. SOCKET SET
CHANNEL LOCK PLIERS
VOLT-OHMMETER
5/16-IN. AND 1/4-IN. NUT DRIVERS

WARNING
Before cleaning, servicing, performing maintenance or removing the chassis from the wall sleeve, disconnect all power to the unit to avoid the possibility of electrical shock and personal injury. Only trained and qualified service personnel should perform installation and service procedures on these units. Untrained personnel may perform basic maintenance tasks such as cleaning and replacing filters. Refer to GENERAL DISASSEMBLY section of this manual for proper procedures to disconnect power to 52S units.

The Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Consider the following safety issues:

Prior to performing any service or maintenance on electrical equipment you must Disconnect All Power.

New and unfamiliar tasks should be performed under the supervision of an experienced service technician.

Personal protective equipment, such as safety glasses and work gloves, should be worn.

The floor around the work area should be clean and free of debris.

Make sure tools are the correct tools for the job, and that they are working properly and in good condition.

The 52S unit may weigh up to 150 pounds. Use a lifting device or ask for assistance if the unit must be moved.

BASIC FAN MOTOR ELECTRICAL TESTS
There are 2 basic electrical tests for PSC fan motors that will determine the electrical state of the motor. The first test requires checking the electrical resistance between the motor windings. The second test requires checking the electrical resistance between the motor windings and ground. These tests may be accomplished by performing the following steps:

1. DISCONNECT ALL POWER TO UNIT.

2. Remove the unit from the sleeve and open the control box as detailed in the GENERAL DISASSEMBLY section.

3. Label and disconnect the fan motor wires from the push button switch and capacitor as shown in Figure 5. Two-speed motors have 2 wires on the capacitor and 2 wires on the push button switch. Three-speed motors have 2 wires on the capacitor and 3 wires on the push button switch. Refer to the unit wiring diagram inside the control box.

FIGURE 5 - OPEN CONTROL BOX

4. Measure and record the resistance between the black wire and each of the other wires. Make sure the motor is cool before attempting to measure resistance. The internal thermostat of the motor may be electrically open and will not close until the motor cools. See Figure 64 for typical motor winding resistance measurements. The resistance values in the table are approximate. Values that are within 10% of those listed are acceptable. If the motor in your model is not listed, find a motor of similar horsepower and voltage on the chart and compare it to the resistance measurements of your motor.

FIGURE 64 - TYPICAL 52S FAN MOTORS

5. Measure the resistance of each of the motor wires to the motor casing. The resistance should be infinite. Make sure the motor is cool before attempting to measure resistance. The internal thermostat of the motor may be electrically open and will not close until the motor cools. A motor that has measurable resistance to ground is shorted to ground and must be replaced.

FAN MOTOR REPLACEMENT
Perform the following steps to remove and reinstall the fan motor:

1. DISCONNECT ALL POWER TO UNIT.

2. Remove the unit from the sleeve as detailed in the GENERAL DISASSEMBLY section and place the unit on a large flat surface.

3. Remove the discharge air grille, the aluminum top panel, the top cover, and the discharge air deck as detailed in the GENERAL DISASSEMBLY section under To Access Indoor-Air Section Components (Figures 14 - 17). Save the screws.

4. Remove 5/16-in. screw, located below the motor, that secures the sheet metal air block and the motor ground wire to the partition. Remove the air block.

5. Remove the gusset, and detach the condenser orifice from the outdoor coil as detailed in the GENERAL DISASSEMBLY section under To Access Outdoor-Air Section Components. See Figures 18 and 19.

FIGURE 38 - TUBE INSERTED STRAINER

FIGURE 19 - REMOVING CONDENSER ORIFICE

6. Loosen the mechanical fastener that holds the indoor fan to the fan motor shaft. The indoor fan may be secured to the fan motor shaft by either an Allen screw or a square head bolt. This may require removing the electric heat assembly. If so, refer to the HEATERS section of this manual under Heater Removal.

7. Open the control box as detailed in the GENERAL DISASSEMBLY section. Label and disconnect the fan motor wires from the push button switch and capacitor. Two-speed motors have 2 wires on the capacitor and 2 wires on the push button switch. Three-speed motors have 2 wires on the capacitor and 3 wires on the push button switch. Refer to the unit wiring diagram inside the control box.

8. Using the 5/16-in. nut driver, remove the 2 screws that hold the outdoor coil to the basepan. See Figure 19.

9. Gently lift the outdoor coil up and just outside of the unit basepan. This allows access to the spring clip that secures the outdoor fan to the fan motor.

CAUTION
Do not kink or break the tubes that connect to the coil. The system still has refrigerant in it. Wear gloves, the coil fins are sharp and can cut your hands.

10. WEAR SAFETY GLASSES! Using the adjustable pliers, carefully remove the spring clip that secures the fan to the fan shaft. See Figure 65. Using 2 screwdrivers, gently slide the outdoor fan off the motor shaft. See Figure 66.

FIGURE 65 - SPRING CLIP

FIGURE 66 - REMOVING OUTDOOR FAN FROM MOTOR SHAFT

11. Remove the 3 mounting bolts that secure the fan motor to the partition and remove the fan motor from the unit.

12. Reinstall the new fan motor by reversing Steps 1 through 11.