SERVICING
27 Rev 1
WARNING
Disconnect Electrical Power Supply:
1. Allow device to cool to the surrounding ambient tem-
perature, at least 15 minutes. Device can be very hot if
recently energized.
2. Disconnect leads from PTCR device. Using an ohmme-
ter, test across terminals as shown in the following illus-
tration.
OHMMETER
3. Resistance should be approximately 30
Ω
±30%. Resis-
tance can range from 10 to 100 ohms depending on
device temperature.
S-16 CHECKING FAN AND BLOWER MOTOR
WINDINGS
The auto reset fan motor overload is designed to protect the
motor against high temperature and high amperage condi-
tions by breaking the common circuit within the motor, simi-
lar to the compressor internal overload. However, heat gen-
erated within the motor is faster to dissipate than the com-
pressor, allow at least 45 minutes for the overload to reset,
then retest.
WARNING
Disconnect Electrical Power Supply:
1. Remove the motor leads from their respective connec-
tion points and capacitor (if applicable).
2. Check the continuity between each of the motor leads.
3. Touch one probe of the ohmmeter to the motor frame
(ground) and the other probe in turn to each lead.
If the windings do not test continuous or a reading is
obtained from lead to ground, replace the motor.
S-17 CHECKING COMPRESSOR WINDINGS
WARNING
HERMETIC COMPRESSOR ELECTRICAL TERMI-
NAL VENTING CAN BE DANGEROUS. WHEN INSU-
LATING MATERIAL WHICH SUPPORTS A HER-
METIC COMPRESSOR ELECTRICAL TERMINAL
SUDDENLY DISINTEGRATES DUE TO PHYSICAL
ABUSE OR AS A RESULT OF AN ELECTRICAL
SHORT BETWEEN THE TERMINAL AND THE COM-
PRESSOR HOUSING, THE TERMINAL MAY BE EX-
PELLED, VENTING THE VAPOROUS AND LIQUID
CONTENTS OF THE COMPRESSOR HOUSING AND
SYSTEM.
If the compressor terminal PROTECTIVE COVER and
gasket (if required) are not properly in place and secured,
there is a remote possibility if a terminal vents, that the
vaporous and liquid discharge can be ignited, spouting
flames several feet, causing potentially severe or fatal injury
to anyone in its path.
This discharge can be ignited external to the compressor if
the terminal cover is not properly in place and if the dis-
charge impinges on a sufficient heat source.
Ignition of the discharge can also occur at the venting
terminal or inside the compressor, if there is sufficient
contaminant air present in the system and an electrical arc
occurs as the terminal vents.
Ignition cannot occur at the venting terminal without the
presence of contaminant air, and cannot occur externally
from the venting terminal without the presence of an exter-
nal ignition source.
Therefore, proper evacuation of a hermetic system is
essential at the time of manufacture and during servicing.
To reduce the possibility of external ignition, all open flame,
electrical power, and other heat sources should be extin-
guished or turned off prior to servicing a system.
If the following test indicates shorted, grounded or open
windings, see procedures S-19 for the next steps to be
taken.
S-17A Resistance Test
Each compressor is equipped with an internal overload.
The line break internal overload senses both motor amper-
age and winding temperature. High motor temperature or
amperage heats the disc causing it to open, breaking the
common circuit within the compressor on single phase
units. The three phase internal overload will open all three
legs.
Heat generated within the compressor shell, usually due to
recycling of the motor, high amperage or insufficient gas to
cool the motor, is slow to dissipate. Allow at least three to
four hours for it to cool and reset, then retest.
