user manual

6
RED DOT
RUN CAPACITOR
FAN
MOTOR
COMPRESSOR
FIGURE 7 RUN CAPACITOR HOOK–UP
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 motors. 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 line side of the capacitor is
marked with a red dot and is wired to the line side of
the circuit (see Figure 7.)
THERMOSTAT
A cross ambient
thermostat is used to
maintain the desired
comfort level. The
thermostat reacts only to a
change in temperature at the
bulb location.
Important to the
successful operation
of the unit is the position
of the sensing bulb in
relation to the evaporator
(see Figure 8).
FIGURE 8 SENSING
BULB LOCATION
CAPACITOR – TEST
1. Remove the capacitor from the unit.
2. Check for visual damage such as bulges, cracks,
or leaks.
3. For dual rated capacitors, apply an ohmmeter lead
to the common (C) terminal and the other probe to
the compressor (HERM) terminal. A satisfactory
capacitor will cause a defl ection on the pointer,
then gradually move back to infi nity.
4. Reverse the leads of the probe and momentarily
touch the capacitor terminals. The defl ection of the
pointer should be two times that of the fi rst check
if the capacitor is good.
5. Repeat steps 3 and 4 to check the fan motor
capacitor.
NOTE: A shorted capacitor will indicate a low
resistance and the pointer will move more to the
“0” end of the scale and remain there as long as
the probes are connected. An open capacitor
will show no movement of the pointer when
placed across the terminals of the capacitor.
SYSTEM CONTROL SWITCH (Figure 6)
This switch is double pole, single throw. Check for
continuity between terminals 2 and 3, and 5 and 6.
FIGURE 6 SWITCH, ON-OFF
RANGE:
Thermostat
(Part No. 618-225-02)
60° F ( ± 2° ) to 90° F( ± 4° )