Supply Fan (Belt-Drive) - Carrier WeatherMaster 50HCQ04-12 Service And Maintenance Instructions

TROUBLESHOOTING THE ECM MOTOR
Troubleshooting the X13 ECM requires a voltmeter.
1. Disconnect main power to the unit.
2. Remove the motor power plug (including the control BRN
lead) and VIO control signal lead at the motor terminals.
3. Restore main unit power.
4. Check for proper line voltage at motor power leads BLK
(at L terminal) and YEL (at N terminal). See Table 2.
Table 2 — Motor Test Volts
Unit Voltage Motor Voltage
208/230
460
575
5. Using a jumper wire from unit control terminals R to G,
engage motor operation. Check for 24v output at the
defrost board terminal IFO.
6. Check for proper control signal voltages of 22V to 28V at
motor signal leads VIO and BRN.
7. Disconnect unit main power. Apply lockout/tagout proce-
dures.
8. Reconnect motor power and control signal leads at the
motor terminals.
9. Restore unit main power.
10. The motor should start and run. If the motor does not start,
remove the motor assembly. Replace the motor with one
having the same part number. Do not substitute with an
alternate design motor as the torque/speed programming
will not be the same as that on an original factory motor.
208/230, 460-v Units
575-v Units
Fig. 7 — ECM Unit Wiring
Min-Max Volts
230 187-253
460 414-506
460 414-506
REPLACING THE X-13 ECM MOTOR
Before removing the ECM belly-band mounting ring from old
motor:
1. Measure the distance from base of the motor shaft to the
edge of the mounting ring.
2. Remove the motor mounting band and transfer it to the
replacement motor.
3. Position the mounting band at the same distance that was
measured in Step 1.
4. Hand-tighten mounting bolt only. Do not tighten securely
at this time.
5. Insert the motor shaft into the fan wheel hub.
6. Securely tighten the three motor mount arms to the support
cushions and torque the arm mounting screws to 60 in.-lbs
(6.8 Nm).
7. Center the fan wheel in the fan housing. Tighten the fan
wheel hub setscrew and torque to 120 in.-lbs (13.6 Nm).
8. Ensure the motor terminals are located at a position below
the 3 o'clock position (see Fig. 5). Tighten the motor
belly-band bolt and torque to 80 in.-lbs (9.0 Nm).

Supply Fan (Belt-Drive)

The belt-drive supply fan system consists of a forward-curved
centrifugal blower wheel on a solid shaft with two concentric
type bearings, one on each side of the blower housing. A fixed-
pitch driven pulley is attached to the fan shaft and an adjust-
able-pitch driver pulley is on the motor. The pulleys are con-
nected using a V-belt. See Fig. 8.
6