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Radial gap, overlap and wheel alignment, Wheel rotation, Radial gap and alignment – Greenheck USF and CSW (479870) User Manual

Page 9

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Utility and Centrifugal Fans

9

®

Wheel Rotation

Rotation direction of the wheel is critical and incorrect
rotation will result in reduced air performance,
increased motor loading and possible motor burnout.

Check wheel rotation by momentarily energizing the
unit and noting if rotation is in the same direction as
the airflow at the outlet and conforms to the rotation
decal affixed to the unit.

Wheels as viewed from the drive side:

NOTE

Model USF and CSW units should be operated only
when attached to the system for which they were
designed. Without proper system static pressure,
the motor could be overloaded.

Airflow

R

o

ta

ti

o

n

R

o

ta

ti

o

n

Airflow

Backward Inclined

Airfoil

Wheels must rotate freely and not rub on the inlet
cone. Model USF and CSW wheels overlap the inlet
cone. Refer to the table for the proper dimension.

Radial Gap and Alignment

Efficient fan performance can be maintained by having
the correct radial gap, overlap and wheel alignment.
These items should be checked after the fan has been
in operation for 24 hours and before start-up when the
unit has been disassembled.

Radial Gap: Adjust inlet cone
position such that the radial gap
between the wheel cone and inlet
cone is evenly distributed around
the wheel.

Radial gap is adjusted by
loosening the inlet cone/ring bolts
and centering the cone/ring on the
wheel. If additional adjustment is
required to maintain a constant
radial gap, loosening the bearing
bolts and centering the wheel is
acceptable as a secondary option.

Overlap: Overlap is adjusted by loosening the wheel
hub from the shaft and moving the wheel to the
desired position along the shaft.

The transition between the inlet cone and wheel
should be as shown; there is a smooth feel to the
profile when moving from one component to the other.

Method for Centering Wheel: On belt drive units,
centering can be accomplished by (a) loosening
the inlet cone bolts to move the inlet cone or by (b)
loosening the bearings in order to move the shaft.
Wheel and inlet cone overlap can be adjusted by
loosening the wheel hub set screws and moving the
wheel to the desired position. Tighten all fasteners
and set screws securely and realign drive pulleys after
adjustment.

Wheel

Cone

Radial
Gap

Radial
Gap

Overlap

A

Straight
Edge

Straight
Edge

Inlet

Cone

Inlet

Cone

Radial Gap, Overlap and Wheel Alignment

Radial Gap and Overlap Dimensions

USF-200 USF-300 USF-400 CSW

A

Overlap

Overlap

Tolerance

inches (mm)

206

306

-

-

-

207

307

-

-

-

208

308

-

-

-

210

310

4

15

16

(125)

3

8

(10)

1

8

(3)

407

7

1

7

16

(37)

2

15

32

(63)

1

8

(3)

408

8

2

11

16

(68)

1

7

32

(31)

1

8

(3)

409

9

3

11

16

(94)

7

32

(6)

1

8

(3)

410

10

3

11

16

(94)

7

32

(6)

1

8

(3)

212

312

412

12

4

1

4

(108)

11

32

(9)

1

8

(3)

213

313

413

13

4

11

16

(119)

3

8

(10)

1

8

(3)

215

315

415

15

5

3

16

(132)

7

16

(11)

1

8

(3)

216

316

416

16

5

3

4

(146)

7

16

(11)

1

8

(3)

218

318

418

18

6

3

8

(162)

15

32

(12)

1

8

(3)

220

320

420

20

7

(178)

1

2

(13)

3

16

(5)

222

322

422

22

7

13

16

(198)

17

32

(13)

3

16

(5)

324

424

24

8

5

8

(219)

9

16

(14)

1

4

(6)

327

427

27

9

7

16

(240)

11

16

(17)

1

4

(6)

330

430

30

10

9

16

(268)

11

16

(17)

3

8

(10)

333

433

33

11

7

16

(291)

15

16

(24)

3

8

(10)

336

436

36

12

3

4

(324)

15

16

(24)

3

8

(10)

340

440

40

14

3

16

(360)

29

32

(23)

3

8

(10)

344

444

44

15

9

16

(395) 1

1

8

(29)

3

8

(10)

349

449

49

17

1

8

(435)

1

1

4

(32)

1

2

(13)

54

18

13

16

(478) 1

17

32

(39)

1

2

(13)

60

20

15

16

(532) 1

9

16

(40)

1

2

(13)

66

22

7

8

(581) 1

29

32

(48)

1

2

(13)

73

25

1

2

(648) 1

29

32

(48)

1

2

(13)