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Frequently Asked Fan Questions
1. How do you adjust a pulley?
  There is an adjustable sheave on the motor. There are two hex set screws on the pulley. One secures the pulley to the shaft. The other allows the two halves of the pulley to be adjusted closer together or further apart. Be sure when adjusting retighten the set screws on a flat side of the pulley base. Adjusting the halves closer together increases the fan speed, further apart slows it down. Double grove pulleys must be turned the same number of turns or the belts will not seat properly in the groves. Always check motor amperage after adjusting pulleys.
2. Can I order a fan without a motor?
  Yes, most fan models can be ordered this way. This is called a fan shell. It is a complete fan less the drive package. The drive package is the motor, pulley, and belts.
3. How do you replace a pulley?
  Single groove pulleys are usually easy to remove after loosening the set screw. Larger pulleys that have a tapered compression bushing are removed by taking out the two hex bolts and placing them in the other two holes. When tightened the bushing will pop out and the pulley can be removed. When replacing make sure the taper of the pulley and bushing match.
4. The fan is vibrating. What is wrong?
  Several things can cause vibration. Before assuming the wheel is unbalanced, check other possible causes first. Look for any obvious signs of a rag or foreign object stuck in the wheel. Another common problem is the fan was recently cleaned and not all the grease was removed from the wheel causing it to be out of balance. Mechanical problems can be the motor, belt, bearings, or wheel. Remove the belt and run only the motor if it vibrates replace motor. Check the belt. If it is in poor condition replace. Make sure the blower pulley and the motor pulley are in alignment. Check bearings for wear or damage. They may also need lubrication. Finally make sure that the fan is secured to the curb. Just adding an extra screw can sometimes quite a noisy fan. If a fan is operating outside its performance range it will also vibrate.
5. The fan leaks when it rains.
  First you need to verify if the water is leaking inside or outside the duct. If the water is inside the exhaust plenum, the area behind the filters, the grease drain on the fan may be clogged and the water is overflowing the venturi on the lower baffle assembly. For a parts breakdown, see the Exploded Parts Detail. The silicon seal between the baffle assembly and the fan base could also be the cause of the leak. If the water is leaking outside the duct and is dripping on the outside of the plenum or collecting in the light fixtures the problem is probably the curb was not flashed to the roof properly.
6. The fan motor shut off and starts again after several minutes.
  The motor is probably shutting off on thermal overload. The motor is overheating and restarts after it cools down and the thermal overload resets. This only happens with single phase motors that are thermally protected. The name plate will tell you if it has internal protection. First measure the amp draw while the motor is running and compare it with the nameplate. If it is not much higher you may only need to slow the fan down until it is at or below the running amps indicated on the name plate. If slowing the fan down is not an option you need to replace the motor with a larger HP motor. Lastly it could be a defective motor.
7. The fan overload trips.
  The overload provides protection for motors without internal thermal protection. This is on all three phase and large single phase motors. If a motor over amps or the current draw on the incoming power leads is unbalanced the overload will trip. Overamping can be the result of using a motor not large enough or running the fan at higher RPM's than needed. If you can slow the fan down this should be your first choice. If this is not an option replace the motor with a larger HP one. Unbalanced loads can be the result of a defective motor or unbalanced power supply. If one of the lines of a 3-phase power supply has lost it's voltage the motor will run on only two lines and overamp. Another common cause of overload tripping is a lightening storm or power outage. When the power comes on again voltage is usually low because of the great demand on the power grid. As voltage goes down the amperage goes up and the overload trips.
8. The exhaust fan is not performing as well as it did in the past.
  This could be the result of a loose or worn belt. Other possible causes are dirty or clogged filters or the fan wheel is loaded with grease.
9. The supply fan is not performing as well as it did in the past.
  This could be the result of a loose or worn belt. Other possible causes are dirty or clogged filters located in the unit on the roof.
10. The exhaust fan won't shut off when I turn the switch off.
  If the hood system was provided with our control panel the system is probably in fire condition. In this mode the exhaust fan will not shut off and the supply fan will not come on. Other possible causes are the R1 relay is bad in the control panel, the fan switch is defective, or the contactor is stuck in the closed position.
11. The supply fan will not turn on.
  If the hood system was provided with our control panel the system is probably in fire condition. In this mode the exhaust fan will not shut off and the supply fan will not come on. Other possible causes are the R1 relay is bad in the control panel, or the contactor coil is open.
12. Dust and pollen is coming through the supply duct.
  Super Filter Coat is a water soluble adhesive applied to the mesh filter after each washing. The adhesive is characteristic of fly paper as it will trap the dust and dirt particles from the airstream. This is available from our website. It is part number 412.
13. Is ETL the same as UL?
  Yes, both are Nationally Recognized Testing Laboratories that test, certify and inspect products for safety and performance for manufacturers. The standard to which CAS hoods are tested is UL 710, Exhaust fans are tested to UL Standards UL 762 & UL 705. You can visit this link for a comparison.
14. The motor on a direct drive fan is running at higher amps than the nameplate lists.
  On direct drive motors the FLA listed on the nameplate is the amperage at its highest speed. The speed control reduces the speed of the motor by lowering the voltage supplied. Basic electric laws dictate that when you decrease the voltage the amperage increases. This is normal for these types of motors. Speed controls used on direct drive fans are rated higher than the motor to accommodate this increase.
15. Is there a comparison of fan noise to noises we recognize?
  Yes. View the comparison.
16. How do you change the voltage of a fan in the field?
  All motors are suitable for high and low voltage applications. Single phase motors are rated 115/208-230. This means the low voltage is 115 volts and the high is 208-230. Similarly three phase motors are rated 208-230/460. This means that the low voltage is 208-230 and the high voltage is 460.

To change the supply voltage, refer to the diagram on the motor label for wiring instructions.

If a prewire is included on the job you will need to replace the contactors and/or overloads because of the change in FLA (refer to the motor label).

If the supply fan is a heater, one will need to rewire the KVA transformer for the new voltage.

NOTE: A single phase motor cannot be converted to three phase and a three phase cannot be converted to single phase. The motor must be replaced.

17. Does adding an explosion proof motor to a fan make it explosion proof?
  Simply adding an explosion proof motor to a fan does not make it explosion proof. Explosion proof fans have to be modified to meet the AMCA requirements listed below. In some jurisdiction, explosion proof switches and filled conduits have to be provided due to these variations in design we do not offer an AMCA construction.

The term "Explosion Proof Exhaust Fans" must be quantified as to its true definition. There is no such thing as "Explosion Proof" either in exhaust fans, blowers or motors. Fans can be manufactured to be "Spark and/or Explosion Resistant". The Air Movement and Conditioning Association (AMCA) has three classifications for "spark resistant" fans and blowers. These are defined as AMCA Types A, B or C spark resistant construction. Type A construction requires that all materials of the fan or blower that are "in contact with the air stream" be made of spark resistant nonferrous material such as aluminum or brass. Type B construction requires a nonferrous wheel and a rubbing ring around the hole where the fan or motor shaft enters the fan or blower housing. Type C construction requires a nonferrous plate on both sides of the inside of the fan or blower housing. The type of construction you require is dependant on the ambient location and/or application severity your fan will be subjected to. You need to be very careful in selecting which type of spark resistant construction you require and specify. If you are not knowledgeable in this area, you should hire a consultant that is.

Explosion Proof motors are not guaranteed to be explosion proof either. They are designed so "if there is an explosion within the motor, the motor design will contain the explosion within the motor and not allow it to go to atmosphere". Explosion proof motors are designed or rated by Classes, Groups and "T" Codes for the atmospheres they will be operating in. If an explosion proof motor is improperly selected for the actual ambient atmosphere it is operating in, it can cause an explosion. Again, if you are not knowledgeable in specifying what type of explosion proof motor you require for your application, rely on someone that is trained in this area.


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