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Big Ass Fans - FAQ

1. How much space is required above the fan?
To provide maximum airflow, the fan should not be placed too close to the ceiling. The minimum amount of space needed between the fan
and the ceiling depends on the size of the fan. (note: space between fan and ceiling can include roof support structure as long as air is free to
circulate). Big Ass Fans recommends the following amount of space between the fan and the ceiling:
• 8-12 ft dia. needs 3 ft (0.9 m) space*
• 14-18 ft dia. needs 4 ft (1.2 m) space*
• 20-24 ft dia. needs 5 ft (1.5 m) space*
*Add additional 2 ft for PowerfoilPlus™ fans.
2. How much clearance is needed for the foils?
All fans must be installed to allow airfoils a minimum clearance of 2’ (61 cm) away from any obstructions (lighting, cranes, sprinklers, etc).
3. What is the best height above the floor for the fan?
The ideal height for the fans is equal to two times its diameter. With that said, I can tell you that we don't have a lot of 24' fans located 48' above the floor. We do have hundreds of happy customers with fans that are mounted anywhere between 12' and 90' above the floor. Most fans are between 18' and 30' above the floor, but this is not always possible.
4. How much does one of those things weigh?
The weight of the fan depends upon its size and design. The 6' fan is under 75 lbs. The 24' Powerfoil X fan is 446 lbs. (202 Kg). Add 30 lbs. for the Single Pivot Fan Mount.
5. Won't the fan just bring the hotter air from the top of the building down on people?
During the warmer months, the fans are run at higher speeds to circulate the air within a facility. This circulation results in an even temperature
throughout the area covered by the fans. Even though the actual temperature is not lowered, people are more comfortable because they are
cooled by the breeze created by the fans. During the cooler months, the fans are run at lower speeds to push warm air down from the ceiling to the floor without creating a cooling breeze.
6. How should the motor junction box be wired?
Refer to the Big Ass Fan Installation Instructions booklet for illustrations showing how to configure the motor wiring.
7. What kind of wire should be used for the motor leads?
Always use wire that is rated for 600V and 75 to 90 degrees C in metallic conduit. For applications not requiring shielded cable, use THHN or THNW. If shielded cable is necessary, RHH or RHW-2, Beldon 29501 through 29507, and Shawflex 2ACD or 3ACD are all good choices.
8. I have a single-phase fan control, but the motor is three-phase only? Will this discrepancy cause a problem?
The heart of the fan control is a variable frequency drive (VFD). The VFD is an inverter that converts 120V~230V single-phase input to 230V three-phase output.
9. What kind of maintenance is recommended for the fans?
Minimal maintenance of the fans is recommended annually. The blades should have dust and dirt removed, and all fasteners should be re-torqued. The fan should be inspected for wear and for evidence of oil leaks (see the preceding two questions). The motor wiring connections should also be checked. A "tug test" of wire connections at the fan control should be performed every six months.
10. How much oil is the gear reducer supposed to have?
The gear reducer is filled with the correct amount of lubricating oil by the manufacturer. It is not necessary to check the oil level.
11. Do I need to change the oil in the gear reducer, and if so, what is the recommended lubricant?
Servicing the gear reducer with lubricating oil is not required. It is designed to last for life.
12. I have a three-fan control. How can I individually control each fan?
Individual control is not possible when multiple fans are connected to a single controller.
13. What are the electrical current requirements for the fan?
The FLA (full-load amp) ratings vary with fan size and voltage. Refer to the Big Ass Fans installation guide for input current requirements per fan size and quantity.
14. We have a problem with employees changing the fan's speed setting. Is there a way to limit access to the controls?
We can supply lockable covers for the rotary on/off and speed control switches that are used on all controls built with metal enclosures. These lockable covers limit access to the fan controls to those in possession of a key.
15. Do I have to use the fan control? Why can't we just wire the fan through an on/off switch?
The fan controls are a whole lot more than just a way to control the speed of the fan. Their primary function is to protect the fan motor and gear reducer from destructive electrical and mechanical forces. The VFD does not allow the fan motor to be damaged by running on current that is higher than it is capable of tolerating. It also starts and stops the fan gradually, so the gear reducer is not subjected to excessive torque loads. This protection is required in order to maintain the Big Ass Fan warranty.
16. Can I feed multiple fan controls from one branch circuit?
Yes, as long as that circuit is sized correctly. Each fan control is internally fused. The circuit must be sized for the total of the individual internal fuses. Therefore, three fan controls, each of which has internal fusing at 10 amps, must be on a 30 amp circuit.
17. Can we interface the fan with our fire suppression system?
Yes. We can provide a schematic that shows the correct way to achieve this while maintaining the proper operation of the fans.
18. Can Big Ass Fans operate on 208-volts?
Yes, the 230-volt controls will accept input from 180 to 265-volts. We do need to know if you need single- or three-phase controls.