S-15B Capacitance Check; S-16A Checking Fan & Blower Motor; Windings (Psc Motors); S-16B Checking Fan & Blower Motor (Ecm Motors) - Goodman ASX Service Instructions Manual

SERVICING

S-15B CAPACITANCE CHECK

Using a hookup as shown below, take the amperage and
voltage readings and use them in the formula:
VOLTMETER
AMMETER
TESTING CAPACITANCE
WARNING
Discharge capacitor through a 20 to 30 OHM
resistor before handling.
Capacitance (MFD) = 2650 X Amperage
S-16A CHECKING FAN AND BLOWER MOTOR

WINDINGS (PSC MOTORS)

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, similar
to the compressor internal overload. However, heat gener-
ated within the motor is faster to dissipate than the compres-
sor, allow at least 45 minutes for the overload to reset, then
retest.
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.
32
15 AMP
FUSE
CAPACITOR
Voltage
1. Remove the motor leads from its respective connection
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-16B CHECKING FAN AND BLOWER MOTOR
(ECM MOTORS)
An ECM is an Electronically Commutated Motor which offers
many significant advantages over PSC motors. The ECM has
near zero rotor loss, synchronous machine operation, vari-
able speed, low noise, and programmable air flow. Because
of the sophisticated electronics within the ECM motor, some
technicians are intimated by the ECM motor; however, these
fears are unfounded. GE offers two ECM motor testers, and
with a VOM meter, one can easily perform basic trouble-
shooting on ECM motors. An ECM motor requires power (line
voltage) and a signal (24 volts) to operate. The ECM motor
stator contains permanent magnet. As a result, the shaft
feels "rough" when turned by hand. This is a characteristic of
the motor, not an indication of defective bearings.
WARNING
Line Voltage now present.
1. Disconnect the 5-pin connector from the motor.
2. Using a volt meter, check for line voltage at terminals #4
& #5 at the power connector. If no voltage is present:
3. Check the unit for incoming power See section S-1.
4. Check the control board, See section S-40.
5. If line voltage is present, reinsert the 5-pin connector and
remove the 16-pin connector.
6. Check for signal (24 volts) at the transformer.
7. Check for signal (24 volts) from the thermostat to the "G"
terminal at the 16-pin connector.
8. Using an ohmmeter, check for continuity from the #1 & #3
(common pins) to the transformer neutral or "C" thermo-
stat terminal. If you do not have continuity, the motor may
function erratically. Trace the common circuits, locate
and repair the open neutral.
9. Set the thermostat to "Fan-On". Using a voltmeter, check
for 24 volts between pin # 15 (G) and common.
10. Disconnect power to compressor. Set thermostat to call
for cooling. Using a voltmeter, check for 24 volts at pin #
6 and/or #14.
11. Set the thermostat to a call for heating. Using a voltmeter,
check for 24 volts at pin #2 and/or #11.