Adjusting Fan Blade Pitch
The trial pitch is the calculated setting for design conditions (water rate , heat load, air density, and brake horsepower). The trial pitch is provided by SPX (see page 2).
1–Select a position on the fan circumference and rotate each blade to this common location when setting or checking blade pitch. Sup- port the blade tip to maintain a common rotation plane while setting the fan pitch. The pitch is set 3⁄16" (5 mm) inboard of the blade tip by placing a protractor on top of a parallel sided straight edge that extends across blade width as shown in Figure 4.
2–Be sure all blades are positioned correctly on hub, then set the pitch. Blades should be within ± 1⁄4° of the desired pitch angle. After the desired setting is obtained, progressively tighten the hardware according to Table 5. Recheck the pitch angle. If required, loosen the hex nuts and reset the pitch as necessary until the proper pitch angle is obtained.
| Bolt | Torque Wrench Setting |
| Diameter | | | |
| ft·lbƒ | N·m |
| |
| 3⁄8" | 40 | 55 | |
| 5⁄8" | 100 | 136 | |
