Bryant Preferred 549K 04-06 Service And Maintenance Instructions page 7

TROUBLESHOOTING THE ECM MOTOR
Axion™ Fan Technology motors are designed with several
built-in protections included in the motor software. If the motor
detects a fault it will safely shut down. For temperature related
faults the motor requires a line voltage reset to continue opera-
tion. For all others, the motor will resume operation automatical-
ly as soon as the fault condition is cleared. See Table 2 for a
complete list.
Table 2 — Fault Condition/Reset Trigger
Fault Reset
Condition Trigger
Phase Failure Automatic
Locked/ Blocked
Automatic
Rotor
Motor Over
Manual
Heated
Power Module
Manual
Over Heated
Line Under-
Automatic
voltage
Communication
Automatic
Error
Troubleshooting the motor requires a voltmeter.
1. Disconnect main power to the unit.
2. Disconnect motor plug in supply section of the unit.
3. Restore main unit power.
4. Check for proper line voltage at motor power leads Black
(PL1-1), Yellow (PL1-2), and Blue (PL-3). Blue is only
present on 3-phase motors. See the following table.
549K Unit Voltage
208/230
460
575
5. Disconnect main power.
6. Reconnect motor plug in supply section of unit.
7. Restore main power.
8. Check for proper motor control voltage signal of 9.7Vdc
to 10.3Vdc at IFM-1 and IFM-3 on Unit Control Board
(UCB). See Fig. 9.
9. Using a jumper wire from unit control terminals R to G,
engage motor operation.
10. Verify control signal from user speed selection switch by
placing voltmeter taps in provided terminals marked Vdc.
Signal should be between 3.8Vdc and 10.3Vdc.
11. If the motor does not start and run, remove the fan assem-
bly and replace the motor with one having the same part
number. Do not substitute with an alternate design motor
as the voltage/speed programming will not be the same as
that on an original factory motor.
Removing the Motor and Fan Assembly
NOTE: Due to press fit design of composite Rotor on Motor, it is
highly recommended that any time a motor is replaced the fan
rotor is replaced as well. The rest of the assembly may be reused.
See Fig. 10.
1. Unplug motor harness from control box harness and cut
wire tie at the fan deck.
2. Unplug connectors from stator temperature limit switch.
3. Remove two screws at front of stator on fan deck.
4. Slide fan assembly forward a couple of inches to clear rear
brackets and lift assembly out.
Description
One phase is missing or imbalanced. In
this case the motor will come to a stop
and then automatically restart when all
phases are present.
The rotor is blocked. Once the locking
mechanism has been removed, the
motor will automatically restart.
The motor will stop in the event the
motor over heats. In this case there has
to be a manual restart.
The motor will stop in the event the
electronics over heat. In this case there
has to be a manual restart.
Once the line voltage returns within
permitted operating range, the fan will
automatically restart.
Internal communication error of the
fan's electronics. The fan will restart
automatically, if error is cleared.
Motor Voltage Min-Max Volts
230 190-250
230 210-250
460 420-500
Fig. 9 — Supply Fan Control Wiring Diagram
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Fig. 10 — Fan Assembly Removal
Disassembling Motor and Fan Assembly
See Fig. 11.
1. Remove six screws from retaining rings in the top of the
fan rotor.
2. Remove rotor from motor.
3. Remove four screws connecting motor to stator flange.
4. Remove stator from motor.
5. If required, remove stator limit switch on aluminum stator.
6. Remove three screws from the heat shield. Retain the heat
shield if a new heat shield has not been ordered.
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