110
SERVICING
VARIABLE SPEED (ECM) MOTOR TEST
(Cooling Low-Stage Call)
THERMOSTAT LOW INPUT(S): R, Y1, G
First, low voltage readings are measured with the 16-pin wire
harness disconnected from the motor. A diagram of the har-
ness and pin locations is provided below. Voltage measure-
ment is AC or DC as specified in the chart below under the
(Volts) column. Set your voltage meter to the proper AC or
DC reading as requested below.
ECM Motor Not Coming On
In order for the cooling fan speed to operate, the integrated
control board has to receive (Y1) signal from the thermostat.
Turn the thermostat to the Cooling 1st stage position. If the
fan will not run, verify 24 volts on the integrated control boards
low voltage terminal strip at (C) and (R) with your volt meter.
If you have 24 volts, place a jumper wire between the (R),
(YL0) and (G) terminal on the control board. If the motor now
operates then you have a problem in the thermostat or ther-
mostat cable. If the motor does not operate, check for high
voltage at the 5-pin connector on the motor.
You should have approximately 120 volts all the time to the
motor. Failure to receive power could be faulty harness, loose
connection or faulty inductor.
Unplug the 16-pin harness from the ECM motor. Set volt
meter to read AC volts. Place your voltage meter on Pin
1(Common) and Pin 12 (R), you should read 24 AC volts.
Finally, check between Pin 1(Common) and Pin 15 (G), you
should read 13 AC Volts. Next, check between Pin 1 (Com-
mon) adn Pin 6 (Y1), you should read 24 AC volts.
You MUST have all of these low voltage readings before the
ECM motor will come on. If you DO NOT have these read-
ings you may have a 16-pin wire harness or integrated con-
trol board problem.
We highly recommend using the GE TECMate PRO™ model
ECM motor tester. This low cost test instrument will verify
whether the motor itself is good.
/-
Y 1
COOL
COMMON 2
COMMON 1
OUT +
EM HT/W2
24VAC (R)
BK/Pwm (Speed)
O (Rev Valve)
8
16
CONTROL CONNECTOR
"Motor Half“
(Viewed from connector end)
(1) This input must be active for motor to operate.
(2) 0 VAC indicates humidistat is calling for dehumidification.
(3) These two pins form an output circuit that powers the CFM LED on the ignition control or interface board.
(4) Dipswitch settings determine measure voltage.
(5) Voltage is measured with 16-wire harness disconnected from motor. Voltage measurement is AC or DC as specified in the chart.
Description
Pin
Volts
(5)
Signal Indicates
Com, C1
1
0 VAC
Common
W/W1
2
0 VAC
W1 = OFF
Com, C2
3
0 VAC
Common
0 VAC
Delay Tap = A
≥
10 VDC
Delay Tap = B
≤
-10 VDC
Delay Tap = C
24 VAC
Delay Tap = D
0 VAC
Cool Tap = A
≥
10 VDC
Cool Tap = B
≤
-10 VDC
Cool Tap = C
24 VAC
Cool Tap = D
Y1
6
24 VAC
Y1 = ON
0 VAC
Adjust Tap = A
≥
10 VDC
Adjust Tap = B
≤
-10 VDC
Adjust Tap = C
24 VAC
Adjust Tap = D
Out -
(3)
8
0 VDC
Common
O
9
0 VAC
O = OFF
Bk/PWM
(2)
10
24 VAC No Dehumidification
0 VAC
Heat Tap = A
≥
10 VDC
Heat Tap = B
≤
-10 VDC
Heat Tap = C
24 VAC
Heat Tap = D
R
12
24 VAC
R = ON
EM/W2
13
0 VAC
EM/W2 = OFF
Y/Y2
14
0 VAC
Y/Y2 = OFF
G
(1)
15
≥
13 VAC
G = ON
Out +
(3)
16
0-3.5 VDC
CFM LED
Thermostat Input(s): R, Y1, G
Heat
(4)
11
Adjust
(4)
7
Delay
(4)
4
5
Cool
(4)