Specifications
111
Evaporator Fan Coupling Assembly — If the cou-
pling has been removed for other blower assembly component
repair or replacement, it is critical that the coupling be reassem-
bled and aligned correctly to prevent premature failures.
REASSEMBLING THE COUPLING INTO THE UNIT
(Fig. 37)
1. Prior to reassembling the coupling, loosen the 4 bearing
mounting bolts, which secure the 2 bearings on either side
of the coupling. Remove the drive belts.
2. Reassemble the coupling with the bearings loose. This
allows the coupling to find its own self-alignment position.
3. Check the hub-to-shaft fit for close fitting clearances.
Replace hubs if high clearances are determined.
4. Check the key for close-fitted clearances on the sides and
0.015 in. clearance over the top of the key. Replace key if
necessary.
5. Be sure that hub flanges, flex members, spacer, and hard-
ware are clean and free of oil.
6. Place the flanges onto the shafts with the hub facing out-
ward. Do not tighten the set screws at this time.
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.
NOTES:
1. Torque set screws on blower
wheel to 70 in. lb ± 2in.lb.
2. Torque set screw on propeller
fanto15in.lb± 2in.lb.
3. Dimensions are in inches.
Fig. 34 — Typical Gas Heating Section
Fig. 35 — Gas Heat Section Details
Fig. 36 — Evaporator-Fan Alignment
and Adjustment