SERVICING
31
WARNING
1. Disconnect power to the furnace.
2. Disconnect the 5-circuit power connector to the ECM
motor.
3. Turn on power to the furnace.
WARNING
4. Measure voltage between pins 4 and 5 on the 5-circuit
connector. Measured voltage should be the same as
the supply voltage to the furnace.
5
4
3
2
1
Lines 1 and 2 will be connected
for 120VAC Power Connector
applications only
Gnd
AC Line Neutral Connection
AC Line Hot Connection
}
5
4
3
2
1
Lines 1 and 2 will be connected
for 120VAC Power Connector
applications only
Gnd
AC Line Neutral Connection
AC Line Hot Connection
}
inductor
5. Measure voltage between pins 4 and 3. Voltage should
be approximately zero.
6. Measure voltage between pins 5 and 3. Voltage should
be the same as the supply voltage to the furnace.
7. If no voltage is present, check supply voltage to the
furnace.
8. Disconnect power to the furnace. Reconnect the
5-circuit power harness disconnected in step 2.
1. Turn on power to the furnace.
WARNING
2. Check voltage between pins 1 and 4 on the 4-wire motor
control harness between the motor and control board.
Voltage should be between 3 and 15 VDC.
3. If no voltage is present, check control board.
WARNING
1. Disconnect power to the furnace.
2. Disconnect the motor control harness and motor power
harness.
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