Carrier 48/50AJ Evaporator Fan Service and Replacement, Evaporator-FanMotor Replacement

CENTER DRIVE	FLEX	SHAFT	SHAFT	BEARINGS
SHAFT	MEMBER	FLANGE

A50-5146

Fig. 41 — Evaporator Fan Coupling

7.Outside of the unit, assemble the flex members to the cen- ter drive shaft with 4 bolts and nuts. The flex members have collars that need to be inserted into the smaller hole of the drive shaft flange.

8.Assemble the flex member/drive shaft assembly to one of the shaft flanges, using 2 bolts and nuts. Slide the other shaft flange towards the assembly and assemble using 2 bolts and nuts. If the shafts are not misaligned, the collar in the flex member should line up with the shaft flange holes.

9.Torque nuts properly to 95 to 100 ft-lb. Do not turn a cou- pling bolt. Always turn the nut. Always use thread lubri- cant or anti-seize compound to prevent thread galling.

10.The ends of the shafts should be flush with the inside of the shaft flange. Torque the set screws to 25 ft-lb.

11.After assembly is complete, slowly rotate the shafts by hand for 30 to 60 seconds.

12.Tighten the bearing mounting bolts, using care not to place any loads on the shaft which would cause flexure to the shafts.

13.Reinstall drive belts. (Refer to Belt Tension Adjustment section below.)

14.Visually inspect the assembly. If the shafts are overly mis- aligned, the drive shaft flange will not be parallel with the shaft flanges.

15.Recheck nut torque after 1 to 2 hours of operation. Bolts tend to relax after being initially torqued.

Evaporator Fan Service and Replacement

1.Turn off unit power supply.

2.Remove supply-air section panels.

3.Remove belt and blower pulley.

4.Loosen setscrews in blower wheels.

5.Remove locking collars from bearings.

6.Remove shaft.

7.Remove venturi on opposite side of bearing.

8.Lift out wheel.

9.Reverse above procedure to reinstall fan.

10.Check and adjust belt tension as necessary.

11.Restore power to unit.

Belt Tension Adjustment — To adjust belt tension:

1.Turn off unit power supply.

2.Loosen motor mounting nuts and bolts. See Fig. 42.

3.Loosen fan motor nuts.

4.Turn motor jacking bolts to move motor mounting plate left or right for proper belt tension. A slight bow should be present in the belt on the slack side of the drive while running under full load.

5.Tighten nuts.

6.Adjust bolts and nut on mounting plate to secure motor in fixed position. Recheck belt tension after 24 hours of operation. Adjust as necessary. Refer to Installation In- structions for proper tension values.

7.Restore power to unit.

Evaporator-Fan Motor Replacement

1.Turn off unit power supply.

2.Remove upper outside panel and open hinged door to gain access to motor.

3.Fully retract motor plate adjusting bolts.

4.Loosen the 2 rear (nearest the evaporator coil) motor plate nuts.

5.Remove the 2 front motor plate nuts and carriage bolts.

6.Slide motor plate to the rear (toward the coil) and remove fan belt(s).

7.Slide motor plate to the front and hand tighten one of the rear motor plate nuts (tight enough to prevent the motor plate from sliding back but loose enough to allow the plate to pivot upward).

8.Pivot the front of the motor plate upward enough to allow access to the motor mounting hex bolts and secure in place by inserting a prop.

9.Remove the nuts from the motor mounting hex bolts and remove motor.

10.Replace the locktooth washer under the motor base with a new washer. Be sure that the washer contacts the motor base surface.

11.Reverse above steps to install new motor.

A48-3729

Fig. 42 — Belt Tension Adjustment

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