Carrier 50LJ - Manual (Page 27)

BELT INSTALLATION AND TENSIONING
NOTE: When installing or replacing belts, always use a
complete set of new, matched belts. Mixing belts often
results in premature breakage of the new belts.
1. Turn off unit power.
2. Adjust motor plate so belts can be installed without stretch­
ing over the grooves of the pulley. (Forcing the belts
can result in uneven belt stretching and a mismatched
set of belts.)
3. Before tensioning the belts, equalize belt slack so that it
is on the same side of the belt for all belts. Failure to do
so may result in uneven belt stretching.
4. Tighten belts using the motor plate adjusting bolts.
5. Adjust until proper belt tension ('/
2 -in. deflection with
one finger) is obtained. Be sure to adjust both adjusting
bolts the same number of turns.
6. Check the tension at least twice during the first day of
operation; there is normally a rapid decrease in tension
until the belts have run in. Check tension periodically
thereafter and keep it at the recommended tension.
With the correct belt tension, belts may slip and squeal
momentarily on start-up. This slippage is normal and dis­
appears after wheel reaches operating speed. Excessive belt
tension shortens belt life and may cause bearing and shaft
damage.
PULLEY ALIGNMENT — For proper belt life, the motor
and fan pulleys must be properly aligned. To check:
1. Turn off unit power. See Fig. 27.
2. Place a straight edge against the motor and fan pulleys.
If the pulleys are properly aligned, the straight edge should
be parallel to the belts.
3. If they are not parallel, check that the motor shaft and
fan shaft are parallel. If they are not, adjust the motor
plate adjusting bolts until they are.
4. After verifying that the shafts are parallel, loosen the
setscrews on the motor pulley.
5. Move pulley on the shaft until the pulleys are parallel.
6. To move the sheave on the shaft, loosen the belts. If
necessary, blower pulley can also be moved on the shaft.
INSTALLING FIELD-SUPPLIED ALTERNATE MO­
TOR PULLEY — To install the alternate pulley:
1. Turn off unit power.
2. Loosen belts using motor adjusting bolts until belts can
be removed without stretching them over the grooves of
the pulley.
3. Remove belts.
4. Loosen setscrews on motor pulley.
5. Slide pulley off motor shaft. Make sure setscrews on
new pulley are loose.
6. Slide new pulley onto fan shaft and align it with the fan
pulley as described above.
7. Tighten setscrews.
8. Install belts and tension properly as described above.
CONDENSER FAN — To adjust condenser fans:
1. Turn off unit power.
2. Remove fan guard and loosen fan hub setscrew.
3. See Fig. 20 and adjust fan height using a straight edge
laid across the fan deck.
4. Tighten setscrew and replace rubber hubcap to prevent
hub from rusting to the motor shaft. Fill hub recess with
Permagum if hub has no rubber hubcap.
5. Replace fan guard.
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