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Controls, Start-Up, Operation, Service and ... - Climayoreo

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SUPPLY FAN AND POWER EXHAUST MOTOR<br />

PLATE — Adjust using a 15 / 16-in. wrench on the adjusting<br />

bolts:<br />

1. Loosen holddown bolts. (See Fig. 47.)<br />

2. Turn the adjusting bolts to move the motor mounting<br />

plate toward or away from the fan to loosen or tighten the<br />

belts. Make the same number of turns to each bolt.<br />

3. Retighten holddown bolts.<br />

BELT INSTALLATION AND TENSIONING<br />

IMPORTANT: When installing or replacing belts,<br />

always use a complete set of new, matched belts to prevent<br />

potential vibration problems. Mixing belts often<br />

results in premature breakage of the new belts.<br />

1. Turn off unit power.<br />

2. Adjust motor plate so belts can be installed without<br />

stretching over the grooves of the pulley. (Forcing the<br />

belts can result in uneven belt stretching <strong>and</strong> a mismatched<br />

set of belts.)<br />

3. Before tensioning the belts, equalize belt slack so that it is<br />

on the same side of the belt for all belts. Failure to do so<br />

may result in uneven belt stretching.<br />

4. Tighten belts using the motor plate adjusting bolts.<br />

HOLDDOWN BOLTS<br />

Fig. 46 — Return/Exhaust Fan Motor<br />

Plate Adjustment<br />

Fig. 47 — Motor Plate Adjustment<br />

HOLD-<br />

DOWN<br />

BOLTS<br />

141<br />

5. Adjust until proper belt tension ( 1 / 2-in. [13 mm] deflection<br />

with one finger centered between pulleys) is<br />

obtained. Be sure to adjust both adjusting bolts the same<br />

number of turns.<br />

NOTE: Check the tension at least twice during the first<br />

day of operation, as there is normally a rapid decrease in<br />

tension until the belts have run in. Check tension periodically<br />

thereafter <strong>and</strong> keep it at the recommended tension.<br />

With the correct belt tension, belts may slip <strong>and</strong> squeal momentarily<br />

on start-up. This slippage is normal <strong>and</strong> disappears<br />

after wheel reaches operating speed. Excessive belt tension<br />

shortens belt life <strong>and</strong> may cause bearing <strong>and</strong> shaft damage.<br />

PULLEY ALIGNMENT — For proper belt life, the motor<br />

<strong>and</strong> fan pulleys must be properly aligned. To check, first turn<br />

off unit power. Place a straightedge against the motor <strong>and</strong> fan<br />

pulleys. See Fig. 48. If the pulleys are properly aligned, the<br />

straightedge should be parallel to the belts.<br />

If they are not parallel, check that the motor shaft <strong>and</strong> fan<br />

shaft are parallel. If they are not, adjust the motor plate adjusting<br />

bolts until they are.<br />

After verifying that the shafts are parallel, loosen the setscrews<br />

on the motor pulley. Move pulley on the shaft until the<br />

pulleys are parallel. To move the sheave on the shaft, loosen the<br />

belts. If necessary, blower sheave can also be moved on the<br />

shaft.<br />

INSTALLING REPLACEMENT MOTOR PULLEY (Supply<br />

Fan Only) — To install a field-supplied replacement pulley:<br />

1. Turn off unit power.<br />

2. Loosen belts using motor adjusting bolts until belts can<br />

be removed without stretching them over the grooves of<br />

the pulley.<br />

3. Remove belts.<br />

4. Loosen setscrews on motor pulley.<br />

5. Slide pulley off motor shaft. Make sure setscrews on new<br />

pulley are loose.<br />

6. Slide new pulley onto fan shaft <strong>and</strong> align it with the fan<br />

pulley as described in Pulley Alignment section above.<br />

7. Tighten setscrews.<br />

8. Install belts <strong>and</strong> tension properly as described in Pulley<br />

Alignment section above.<br />

CONDENSER FAN ADJUSTMENT (All Units Except<br />

Size 035)<br />

1. Turn off unit power.<br />

2. Remove fan guard <strong>and</strong> loosen fan hub setscrew.<br />

3. See Fig. 49 <strong>and</strong> adjust fan height using a straight edge<br />

laid across the fan deck.<br />

4. Tighten setscrew to 12.5 to 13.75 ft-lb <strong>and</strong> replace rubber<br />

hubcap to prevent hub from rusting to the motor shaft.<br />

Fill hub recess with Permagum if hub has no rubber hubcap.<br />

5. Replace fan guard.<br />

CONDENSER FAN ADJUSTMENT (Size 035) — Each<br />

fan is supported by a formed wire mount bolted to a fan deck<br />

<strong>and</strong> covered with a wire guard. The exposed end of the fan motor<br />

shaft is protected from weather by grease. If the fan motor<br />

must be removed for service or replacement, be sure to regrease<br />

fan shaft <strong>and</strong> reinstall fan cover, retaining clips, <strong>and</strong> fan<br />

guard. For proper performance, the fans should be positioned<br />

as shown in Fig. 50. Tighten setscrews to 14 1 ft-lb (18 1.3<br />

N-m).<br />

Check for proper rotation of the fan(s) once reinstalled<br />

(counterclockwise viewed from above). If necessary to reverse,<br />

switch leads at contactor(s) in control box.

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