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SERVICING
OUT -
8
ADJUST +/-
7
Y1
6
COOL
5
DELAY
4
3
COMMON2
W/W1
2
COMMON1
1
16-PIN ECM HARNESS CONNECTOR
If you do not read voltage and continuity as described, the
problem is in the control or interface board, but not the
motor. If you register voltage as described, the ECM power
head is defective and must be replaced.
Checking ECM Motor Windings
High Voltage!
Disconnect all power before servicing
or installing. Multiple power sources
may be present. Failure to do so may
cause property damage, personal injury
or death.
1. Disconnect the 5-pin and the 16-pin connectors from
the ECM power head.
2. Remove the 2 screws securing the ECM power head
and separate it from the motor.
3. Disconnect the 3-pin motor connector from the power
head and lay it aside.
4. Using an ohmmeter, check the motor windings for
continuity to ground (pins to motor shell). If the
ohmmeter indicates continuity to ground, the motor is
defective and must be replaced.
5. Using an ohmmeter, check the windings for continuity
(pin to pin). If no continuity is indicated, the thermal
limit (over load) device may be open. Allow motor to
cool and retest.
OUT +
16
15
G (FAN)
Y/Y2
14
13
EM Ht/W2
24 Vac (R)
12
HEAT
11
BK/PWM (SPEED)
10
O (REV VALVE)
9
WARNING
3-pin motor
connector
16-pin
connector
5-pin
connector
Checking Compressor
Hermetic compressor electrical terminal venting can
be dangerous. When insulating material which supports
a hermetic compressor or electrical terminal suddenly
disintegrates due to physical abuse or as a result of an
electrical short between the terminal and the compressor
housing, the terminal may be expelled, venting the vapor 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
discharge 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
external 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
extinguished or turned off prior to servicing a system.
If the following test indicates shorted, grounded or open
windings, see procedure for the next steps to be taken.
Resistance Test
Each compressor is equipped with an internal overload.
The line break internal overload senses both motor
amperage and winding temperature. High motor
temperature or amperage heats the disc causing it to open,
WARNING
17
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