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Centrifugal Downblast Exhaust Fan
Direct Drive for Roof & Wall Mounting

Electrical wiring and connections should be done in accordance with local ordnances and the National Electric Code, NFPA70. Be sure the voltage and phase of the power supply and the wire amperage capacity is in accordance with the motor nameplate. For additional safety information refer to AMCA publication 410-96, Recommended Safety Practices for Users and Installers of Industrial and Commercial Fans.
Upon receiving unit, check for any damage and report it immediately to the carrier. Also check that all accessory items are accounted for.

Installation of this ventilator should only be performed by a qualified professional who has read and understands these instructions and is familiar with proper safety precautions. Improper installation poses serious risk of injury due to electric shock, contact with rotating equipment and other potential hazards. Special considerations resulting from high winds or seismic activity may be required. Consult with a licensed professional engineer for more information if necessary.
  1. Wheel must be free to rotate and should not strike or rub any stationary object.
  2. Follow all local electrical and safety codes, as well as the National Electrical Code (NEC), the Occupational Safety and Health Act (OSHA), and the National Fire Protection Association (NFPA), where applicable.
  3. Motor must be securely and adequately grounded.
  4. Always disconnect power before working on or near a fan. Lock and tag the disconnect switch or breaker to prevent accidental power up.
  5. Caution-when servicing fan, motors may be hot enough to cause pain or injury. Allow motor to cool before servicing.
  6. Secure the power cable to prevent contact with sharp objects.
  7. Do not kink power cable and never allow the cable to come in contact with oil, grease, hot surfaces or chemicals.
  8. Make certain that the power source is compatible with the requirements of your equipment.

Caution: Do not raise ventilator by its apron, wheel, or motor– use a sling or platform

Roof Mounting
  1. Ventilators are designed for installation atop a prefabricated or factory built roof curb. Follow manufacturer’s instructions for proper curb installation.
  2. If a backdraft damper is required, it should be secured within the curb using sheet metal screws, to the bottom of a damper box or damper support flanges located below the roof deck.
  3. Normally the power cord is brought through the conduit tube located between the curb cap and the bottom of the motor compartment.
  4. Secure ventilator curb through vertical portion of the ventilator base assembly flange using a minimum of eight (8) lug screws, anchor bolts, or other suitable fasteners (not furnished). Shims may be required depending upon curb installation & roofing material.
  5. Before connecting fan motor to power source verify power line wiring is de-energized.
  6. Connect power supply wiring to the motor as indicated on the motor nameplate or terminal box cover. Make certain that the power source is compatible with the requirements of your equipment.
  7. Before powering up fan check ventilator wheel for free rotation. Re-center if necessary.
  8. Check all fasteners for tightness.
  9. Re-install motor dome.
Wall Mounting
  1. The same instructions, warnings and notes found under Roof Mounting section will apply. Refer to steps 2 and 3, and steps 5 through 8.
  2. Masonry Wall: Around the wall opening install an angle iron frame at least 2” x 2" x 1/8”. Frame should be approximately ” smaller than the inside base dimension of the ventilator. Secure the lead cinch type anchors with non-ferrous bolts (3 per side). The ventilator should be mounted to the mounting angle with self-taping sheet metal screws (3 per side).
  3. Wood Sidings: Around the wall opening install a wooden frame 2” high x 2” wide. Frame should be approximately ” smaller than the inside base dimension of the ventilator. Secure with counter-sunk expansion type lag bolts (3 per side). The ventilator should then be mounted to the mounting frame with the square head wood screws (3 per side) 3/8” minimum.
  4. The mounting flange connections should be coated with a suitable caulking compound or an approved waterproof mastic sealer.
  5. Wall mount application is not recommended from fans 30” or larger.

  1. Before starting up or operating the ventilator, check all fasteners for tightness. In particular, check the set screw in the wheel hub. With power to the fan OFF or prior to connecting ventilator to power, turn the fan wheel by hand to be sure it is not striking the inlet or any obstacles. Re-center if necessary.
  2. Start the fan up and shut it off immediately to check rotation of the wheel with the directional arrow in the motor compartment. Fan wheel should rotate counter-clockwise when viewed from the top. Reversed rotation will result in poor air performance, motor overloading and possible burnout. For units equipped with a single-phase motor check the motor wiring diagram to change rotation.
  3. When the fan is started up, observe the operation and check for any unusual noises.
  4. With the air system in full operation and all ducts attached, measure the current input to the motor and compare with the motor nameplate to determine if the motor is operating under safe load condition.
  5. Keep inlets and approaches to the ventilator clean and free from obstruction.
  6. To adjust the fan speed, adjust the rheostat. To increase the fan speed, turn the rheostat counter- clockwise. To reduce the fan speed, turn the rheostat clockwise.

  1. Fan inlet and approaches to ventilator should be kept clean and free from any obstruction.
  2. Motors are permanently lubricated. Caution: Use care when touching the exterior of an operating motor. Motors normally run hot and may be hot enough to be painful or cause injury.
  3. To remove motor or Impeller:
    1. Remove motor hood, and electric wire from switch or junction box.
    2. Remove the fastening bolts and nuts that secure the top plate to the supporting braces and remove the entire assembly from the housing.
    3. Loosen setscrew(s) on wheel hub to slip fan impeller from shaft.
    4. To remove motor, remove retaining bolts and nuts on motor mounting plate.
  4. Wheels require very little attention when moving clean air. Occasionally oil and dust may accumulate causing imbalance. If the fan is installed in a corrosive or dirty atmosphere, periodically inspect and clean the wheel, inlet and other moving parts to ensure smooth and safe operation.
  5. All fasteners should be checked for tightness each time maintenance checks are preformed prior to restarting unit.

Problems and Potential Cause

Fan Inoperative
  • Open circuit breaker or overload in starter set too low. Reset circuit breaker or check setting of overload.
  • Motor wired incorrectly. Check motor wiring to wiring diagram located on fan motor.
Insufficient Air or Pressure
  • Fan rotating in the wrong direction. Be sure fan is rotating counter-clockwise looking down on wheel.
  • Poor inlet conditions. There should be a straight clear duct at the inlet.
  • Be sure duct access doors are closed and dampers are operating properly.
Excessive Vibration and Noise
  • Fan rotating in the wrong direction. Be sure fan is rotating counter-clockwise looking down on wheel.
  • Worn motor bearings. Replace or repair motor.
  • Damaged or unbalanced wheel.
  • Fan is operating in the unstable region of the fan curve.
Motor Overload
  • Fan rotating in the wrong direction. Be sure fan is rotating counter-clockwise looking down on wheel.
  • Motor wired incorrectly. Check motor wiring to wiring diagram located on fan motor.
  • Overload in starter set too low.


This equipment is warranted to be free from defects in materials and workmanship, under normal use and service, for a period of 24 months from date of shipment. This warranty shall not apply if:

  1. The equipment is not installed by a qualified installer per the MANUFACTURER'S installation instructions shipped with the product,
  2. The equipment is not installed in accordance with federal, state and local codes and regulations,
  3. The equipment is misused or neglected,
  4. The equipment is not operated within its published capacity,
  5. The invoice is not paid within the terms of the sales agreement.

The MANUFACTURER shall not be liable for incidental and consequential losses and damages potentially attributable to malfunctioning equipment. Should any part of the equipment prove to be defective in material or workmanship within the 24-month warranty period, upon examination by the MANUFACTURER, such part will be repaired or replaced by MANUFACTURER at no charge. The BUYER shall pay all labor costs incurred in connection with such repair or replacement. Equipment shall not be returned without MANUFACTURER'S prior authorization and all returned equipment shall be shipped by the BUYER, freight prepaid to a destination determined by the MANUFACTURER.

Ventilation Direct is committed to customer service and on time, accurate delivery of superior Ventilation products.

Call 1.866.433.8335 for a friendly customer service representative that can customize your exhaust fan, heater or supply air package while providing you a fast quotation including drawings and submittal packages. Our product line includes UL and ANSI listed commercial and industrial exhaust fans, heaters, make-up air units, motors and more with a two year warranty.