Step 9 — Adjust
NOTE: Before adjusting fan speed, make sure the new fan speed will provide an air temperature rise range as shown in Table 1.
To change fan speed:
1.Shut off unit power supply and tag disconnect.
2.Loosen belt by loosening fan motor mounting nuts. See Fig. 41.
3.Loosen movable pulley flange setscrew (see Fig. 42).
4.Screw movable flange toward fixed flange to increase speed and away from fixed flange to decrease speed. Increasing fan speed increases load on motor. Do not ex- ceed maximum speed specified in Table 1.
5.Set movable flange at nearest keyway of pulley hub and tighten setscrew. (See Table 1 for speed change for each full turn of pulley flange.)
To align fan and motor pulleys:
1.Loosen fan pulley setscrews.
2.Slide fan pulley along fan shaft.
3.Make angular alignment by loosening motor from mounting.
To adjust belt tension:
1.Loosen fan motor mounting nuts.
2.Slide motor mounting plate away from fan scroll for proper belt tension
3.Tighten motor mounting nuts.
4.Adjust bolt and tighten nut to secure motor in fixed position.
MOTOR MOUNTING
PLATE NUTS
Fig. 41 — Belt Drive Motor Mounting
DIRECT DRIVE MOTOR | DIMPLED HEAT EXCHANGER |
|
Fig. 40 — | Fig. 42 — |
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