Supply Fan (Belt-Drive) - Carrier WeatherMaster 50HC04 Service And Maintenance Instructions

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.-lb
(6.8 Nm).
7. Center the fan wheel in the fan housing. Tighten the fan
wheel hub setscrew and torque to 120 in.-lb (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.-lb (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. 11.)
460, 575-v Units
208/230-v Units
Fig. 10 — Direct-Drive Supply Fan Assembly Wiring Diagram
MOUNTING
BOLTS (4)
Fig. 11 — Typical Belt Drive Motor Mounting
BELT
Check the belt condition and tension quarterly. Inspect the belt
for signs of cracking, fraying, or glazing along the inside sur-
faces. Check belt tension by using a spring-force tool, such as
Browning's "Belt Tension Checker" (P/N: 1302546 or equiva-
lent tool); tension should be 6 lb at
when measured at the centerline of the belt span. This point is
at the center of the belt when measuring the distance between
the motor shaft and the blower shaft.
NOTE: Without the spring-tension tool, place a straight edge
across the belt surface at the pulleys, then push down on the belt at
mid-span using one finger until a
reached. See Fig. 12.
6
BLOWER PULLEY
V--- BELT
MOTOR
PULLEY
MOTOR
MOTOR MOUNTING
PLATE
/ -in. (1.6 cm) deflection
5
8
/ -in. (1.3 cm) deflection is
1
2