CAPACITORS
WARNING
ELECTRIC SHOCK HAZARD
Turn off electric power before servicing. Discharge capacitor with a 20,000 Ohm 2 Watt resistor before handling.
Failure to do so may result in personal injury, or death.
Many motor capacitors are internally fused. Shorting the terminals will blow the fuse, ruining the capacitor. A 20,000 ohm 2 watt resistor can be used to discharge capacitors safely. Remove wires from capacitor and place resistor across terminals. When checking a dual capacitor with a capacitor analyzer or ohmmeter, both sides must be tested.
Capacitor Check with Capacitor Analyzer
The capacitor analyzer will show whether the capacitor is “open” or “shorted.” It will tell whether the capacitor is within its micro farads rating and it will show whether the capacitor is operating at the proper
Capacitor Connections
The starting winding of a motor can be damaged by a shorted and grounded running capacitor. This damage usually can be avoided by proper connection of the running capacitor terminals.
From the supply line on a typical 230 volt circuit, a 115 volt potential exists from the “R” terminal to ground through a possible short in the capacitor. However, from the “S” or start terminal, a much higher potential, possibly as high as 400 volts, exists because of the counter EMF generated in the start winding. Therefore, the possibility of capacitor failure is much greater when the identified terminal is connected to the “S” or start terminal. The identified terminal should always be connected to the supply line, or “R” terminal, never to the “S” terminal.
When connected properly, a shorted or grounded running capacitor will result in a direct short to ground from the “R” terminal and will blow the line fuse. The motor protector will protect the main winding from excessive temperature.
Dual Rated Run Capacitor
F C H
DEFROST THERMOSTAT
(“WY” Electromechanical Control Models Only)
This thermostat is a single pole - double throw with con- tacts between terminal “2” and “3” closing on temperature rise and contacts between terminals “2” and “1” closing on temperature fall. When the contacts between terminals “2” and “3” open, power to the compressor is interrupted. When contacts between terminals “2” and “1” make, power is suppled to the heater element.
This control is a dual purpose control that acts as an outdoor thermostat and defrost control.
When the sensing bulb, attached to the condenser coil, senses enough icing on the outdoor coil it will interrupt power to the compressor and supply power to the heating element until the coil temperature reaches above 43°. Then the heater will shut off and the unit will resume operating in the reverse cycle mode.
When the outdoor coil temperature drops below 20 degrees, the unit will operate in electric heat mode continuously until the outdoor coil temperature rises above 43°.
Figure 10: Defrost Control
DEFROST BULB LOCATION
(All “WY” Electromechanical Control Models)
The defrost control bulb must be mounted securely and in the correct location to operate properly (see Figure 11).
Figure 11: Defrost Bulb Location
(All “WY” Models)
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