SERVICING
127
USC
1
2
3
4
5
LO HEA T HI HEAT E AC CO OL P A RK L IN E X FMR H UM
HOT NEUT R AL
LO HEA T HI HEAT E AC COOL P A RK L IN E X FMR H UM
CFM
DEHUM
CUT FOR
1
2
3
TSTAT
S4
S3
OFF
ON
S1
S
I
N
G
L
E
T
W
O
ON
OFF
87654321
87654321
B18099-27
EAC
CIRC
HUM
XFMR
LINE
(GMV8, GCV9, GMV9, GMV95)
(WR60V61-289)
4. If voltage is present in Steps 1 through 3 and the in-
duced draft blower is operating, check for 120 volts to
the ignitor during the preheat cycle. Measure voltage be-
tween Pin 1 and Pin 5 (on the 5-pin connector) located
on ignition control. No voltage, check pressure switch or
replace the ignition control board.
5. After the ignitor warmup time, begin checking for 24 volts
to the gas valve. Voltage will be present for seven sec-
onds only if proof of flame has been established.
6. If proof of flame was established voltage will be provided
to the air circulation blower following the heat on delay
period.
a. BEFORE replacing the ECM motor assembly or the
end bell, first check the motor with a GE TECMate
PRO tester. If the motor runs with the tester, the
motor is good. To check the end bell, see the previ-
ous variable speed testing section of this manual be-
fore replacing the end bell.
b. The two-stage variable speed furnaces should have
120 Volts at the motor at all times, even without a call
for cooling or heating. These motors receive their op-
erational signals (24 Volts) through the 16-pin wiring
harness, connected between the motor and integrated
control board. NOTE: For complete troubleshooting
information on units using the ECM/ICM blower mo-
tors, refer to the servicing section - Checking Air Cir-
culator Blowers (S-16B and S-16C) in this service
manual.
Goodman® and Amana® brand 80% and 90% Two-Stage
(AMH8, GME8, GMH8, AMH95, GMH95, GCH9)
NOTE: The models above use White-Rodgers 50M56-289
ignition control board.
1. Check for 120 volts from Line 1 (Hot) to Line 2 (Neutral)
at the ignition control. No voltage, check the door switch
connections and wire harness for continuity.
2. Check for 24 volts from W1 to C terminal on the ignition
control. No voltage. Check transformer, room thermo-
stat, and wiring.
If you have 24 volts coming off the transformer but re-
ceive approximately 13 volts on the terminal board be-
tween (C) and (R), check for blown fuse.
3. Check for 120 volts to the induced draft blower (low-stage)
by measuring voltage between Pin 3 and Pin 4 (on the 5-
pin connector) located on circuit board. No voltage, check
for loose connection in the 5-pin connector or replace
ignition control.
Check for 120 volts to the induced draft blower (high-
stage) by measuring voltage between Pin 2 and Pin 4
(on the 5-pin connector) located on circuit board. No volt-
age, check for loose connection in the 5-pin connector,
no call for high stage heat or replace ignition control.
0130F00006
PARK
PARK
EAC-H LINE-H
XFMR-H
LINE NEUTRAL
LO HEAT-H COOL-H
HI HEAT-H
FAULT
RECALL
150 SEC
1 STG
AUTO
100 SEC
2 STG
5 MIN
H
T
O
F
F
D
L
Y
2
N
D
S
T
G
D
L
Y
MODE
FS
YWR
G
C
K3
K1
K6 K4
K5
K7
K2
(AMH8, GME8, GMH8, GCH8)
WR50M56-289
4. If voltage is present in Steps 1 through 3 and the in-
duced draft blower is operating, check for 120 volts to
the ignitor during the preheat cycle. Measure voltage be-
tween Pin 1 and Pin 5 (on the 5-pin connector) located
on ignition control. No voltage, check pressure switch or
replace the ignition control board.
5. After the ignitor warmup time, begin checking for 24 volts
to the gas valve. Voltage will be present for seven sec-
onds only if proof of flame has been established.
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