Carrier 52S manual Locked OUT, Capacitor Test

CAPACITOR Ð The 52S units use a dual capacitor. One part of the capacitor is used with the fan motor. The other part of the capacitor is used by the compressor.

Run circuits on single-phase compressor motors use capacitors which dramatically affect the motor opera- tion. Run capacitors are connected to the motor circuit at all times.

To evaluate the capacitor, perform a visual check ®rst. A shorted capacitor may give a visual indication of its failure. For example, the pop-out hole at the top of a start capacitor may bulge or blow out. A run capacitor may bulge or leak. In these instances, the capacitor must be replaced with one recommended by the manufacturer.

If there are no visual signs of capacitor failure, testing of the capacitor resistance may be done with a volt- ohmmeter as detailed below:

1.Turn off unit power as described in GENERAL DISASSEMBLY section but do not unplug the service cord; it will supply ground connection for the unit chassis. Check to ensure power is off and

LOCKED OUT.

2.Connect one lead of a 20,000 ohm, 2-watt resistor to the center group of terminals on the dual capacitor. Attach the other lead from the resistor to an un- painted metal section of the unit chassis. This allows that section of the dual capacitor to discharge. Repeat this process between the other group of terminals.

Capacitors are capable of holding charge similar to a battery and may cause an electrical shock.

3.Locate and disconnect the wires from the start and/or run capacitor to isolate them from the remainder of the circuit. Refer to the unit wiring diagram if you need assistance locating wires.

4.Set up the volt-ohmmeter to measure resistance by connecting the meter across the capacitor terminals. See Figure 56.

5.The reading on the meter should ®rst indicate zero, or a low resistance, then slowly rise toward in®nity or some high value or measurable resistance. This indicates the capacitor is most likely good. If the read- ing goes to zero or a low resistance and stays there, the capacitor is likely shorted and needs replace- ment. If the reading immediately indicates in®nity, the capacitor is likely open and must be replaced.

6.Replace the capacitor if failed and rewire according to the WIRING SCHEMATICS located in the control box of the unit.

FIGURE 56 Ð CAPACITOR TEST

FAN CYCLE SWITCH Ð The fan cycle switch has

2 operating modes, continuous (CON) and cycle (CYC). To verify the fan cycle switch is operational, a conti- nuity test may be performed as follows:

1.Turn off unit power as described in GENERAL DISASSEMBLY section.

2.Label and remove the leads connected to fan cycle switch. See Figure 57.

3.Connect the volt-ohmmeter for 1X ohms and check for continuity from terminal 2 to 1 then change the switch position and check for continuity from ter- minal 2 to 3. For a 6-terminal switch this test should be done on terminals 5 to 4 and 5 to 6 as well.

4.Once test is complete, reconnect the leads.

FIGURE 57 Ð FAN CYCLE SWITCH (3 Terminal)

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