CHECKING THE INTERNAL OVERLOAD (see Figure 4.)
1. With no power to unit, remove the leads from the compressor
terminals.
2. Using an ohmmeter, test continuity between terminals C-S
and C-R. If not continuous, the compressor overload is open
and the compressor must be replaced.
Figure 4: Internal overload
6.2 FAN MOTOR
A single phase permanent split capacitor motor is used to drive the evaporator blower and
condenser fan. A self-resetting overload is located inside the motor to protect against high
temperature and high amperage conditions.
FAN MOTOR - TEST
1. Determine that capacitor is serviceable.
2. Disconnect fan motor wires from fan speed switch or system switch.
3. Apply "live" test cord probes on Red wire and common terminal of capacitor. Motor should
run at high speed.
4. Apply "live" test cord probes on Yellow wire and common terminal of capacitor. Motor should
run at mid speed.
5. Apply "live" test cord probes on White wire and common terminal of capacitor. Motor should
run at low speed.
6. Apply "live" test cord probes on each of the remaining wires from the speed switch or
system switch to test intermediate speeds.
6.3 CAPACITOR, RUN
A run capacitor is wired across the auxiliary and main
winding of a single phase permanent split capacitor motor
such as the compressor and fan motor. A single capacitor
can be used for each motor or a dual rated capacitor can
be used for both.
The capacitor's primary function is to reduce the line
current while greatly improving the torque characteristics
of a motor. The capacitor also reduces the line current to
the motor by improving the power factor of the load. The Figure 5: Run capacitor
hook-up line side of the capacitor is marked with a red dot and is
wired to the line side of the circuit (see Figure 5.)
CAPACITOR - TEST
1. Remove capacitor from unit.
2. Check for visual damage such as bulges, cracks, or leaks.
3. For dual rated, apply an ohmmeter lead to common (C) terminal and the other probe to the
Service Manual
Room Air Conditioner with R-410A
Heat Controller, Inc.
11