• General Information
    • Orders & Payments
    • Returns
    1. How do I apply for Credit Terms?

      Please contact our Customer Service department to discuss requirements.

    2. How do I place an order?

      Please contact our Customer Service department with your purchase order number:

      By Telephone: 1-800-779-4021
      By Fax: 1-800-779-4022

    3. How do I check on the status of an order?

      Please contact our Customer Service department with your purchase order number.

    4. How do I cancel or change an order?

      Please contact our Customer Service department with your purchase order number.

      Please note: Written consent may be required for the following: cancellation of order; change of project scope; alteration to contract; change to materials specifications; change to original specified delivery date; any other change that materially affects the contract.  If any of the above should result in loss or additional cost, Vendor reserves the right to seek terms that provide indemnity for any loss, including expenses incurred and commitments made.

    5. How do I arrange for payment of invoices?

      In the USA, Continental Fan accepts the following forms of payment:

      Credit card:
      Master Card, Visa, American Express

      Mail to: Continental Fan Manufacturing Inc.
      P.O. Box 418360 Boston, MA  02241-8360

      Wire Transfer:
      Please contact us at 1-800-779-4021 to arrange.

      In Canada, Continental Fan Canada Inc. accepts the following forms of payment:

      Credit card:
      Master Card, Visa

      Mail to: Continental Fan Canada Inc.
      12-205 Matheson Blvd. E. Mississauga, ON L4Z 3E3

      Wire Transfer:
      Please contact us at 1-800-779-4021 to arrange.

    1. What is the Return Policy?

      1. Special orders, non-stock and obsolete materials are not returnable under any circumstances.
      2. At its discretion, Vendor may issue a Return Materials Authorization (RMA) number and a ship to address for materials to be returned.
      3. Materials returned without an RMA number will not be accepted.
      4. Should you require an RMA, please contact our Customer Service department.
      5. Returned materials are subject to a restocking fee.
      6. All materials assigned an RMA number must be properly packaged and shipped PREPAID.
      7. Collect shipments of returned materials will not be accepted.
      8. A copy of the Bill of Sale to verify purchase date must accompany shipment.
      9. RMA number must be clearly visible on the outside of packaging.
  • Industrial Fans
    • Engineering
    • Glossary Of Terms
    1. How do I determine my airflow requirements?

      Airflow or ventilation requirements often fall into two categories; general ventilation and process ventilation. Airflow requirements for general ventilation are usually determined by the Air Quality Method or by the Air Change Method. While the design process is beyond the scope of this document, the Air Quality Method involves providing the proper amount of outside air (cfm) per person to provide acceptable levels of indoor air quality. The Air Change Method provides a total exchange of air for a given interval of time. Guidelines of air changes for various room designs and acceptable indoor air quality rates are available through ASHRAE and other industry sources.

      Airflow requirements for process ventilation are application specific. Applications may involve removal of fumes, particulates and heat. Please contact our Customer Service department for further information.

    2. Do spark resistant fans have any third party certification?

      Spark resistant fans do not carry any third party certification. Guidelines for spark resistant construction are noted in AMCA Standard 99-0401-86.

    3. What factors prevent a fan from performing as specified?

      There are many reasons why a fan may fail to perform as specified. First, it is important to understand what defines acceptable performance. According to AMCA Publication 200, a fan installed in a ventilation system should expect a tolerance of +/- 7.5% for flow (cfm). For example, a fan which produces 1,000 cfm in a lab environment should provide a volume flow rate of 925 to 1,075 cfm when installed in a properly designed ventilation system. Volume flow rates outside this range are typically the results of variances in system static pressure, known as System Effects, or mechanical problems with the fan.

      Common symptoms include the following:

      • Obstructions in the duct system – closed dampers, closed registers, dirty filters, clogged or dirty coils.
      • Obstructions in the fan inlet – elbows are too close to the inlet, walls are too close to the inlet.
      • Duct design – improperly designed turning vanes, leaks in supply or exhaust ducts.
      • Fan related – impeller running backwards, fan speed too low, impeller dirty or clogged, tolerances between inlet cone and inlet of the wheel are incorrect.


    1. Glossary of Terms



      The volume of air moved by a fan per unit of time, usually expressed in cubic feet per minute (cfm) or meters cubed per second (m³/s).

      Air Horsepower (AHP)

      The measurement of work done by the fan. Theoretically, the required horsepower to drive a fan if it was 100% efficient.
      Formula for Air Horsepower

      Axial Fan

      A fan in which the flow of air is substantially parallel to the axis of rotation.

      Brake Horsepower (BHP)

      The actual horsepower absorbed by the fan. Brake Horsepower is greater than Air Horsepower because no fan is 100% efficient.
      Formula for Brake Horsepower

      Centrifugal Fan

      Any fan with a scroll shaped housing. Air enters from the side of the rotating fan wheel, turns 90 degrees and accelerates due to centrifugal force as it flows over fan blades and exits the fan housing.

      Cubic feet per minute (cfm)

      The volume of air moved by a fan, expressed in cubic feet per minute.


      A mechanical device that regulates airflow through a system.

      Decibel (dB)

      A logarithmic unit used to express sound power and sound pressure levels. Often, sound meters are fitted with filters to approximate the human ear’s response to sound. Common filters are A, B or C; measured results are expressed as dBA, etc.

      Air Density

      The weight of a unit of air volume, commonly expressed as lbs/ft³.

      Fan Laws

      Fan laws are used to express the relationship between several variables involved in fan performance. There are four constants (HP, rpm, cfm, and SP) in all fan applications and designs. Any changes to one constant will impact the others; these changes can be determined with algebraic equations.

      The most commonly used fan laws are as follows:
      Common Fan Laws

      Feet per Minute (fpm)

      Common measurement of the speed of air moved by a fan.


      The rotating part of a fan that transmits energy to the air or gas through which it moves. Also called a propeller or wheel.

      Inches of Water Gauge (in. wg)

      A unit of pressure, expressed in inches of water gauge, used to indicate the difference between absolute or total pressure and the ambient air pressure.

      Outlet Area

      The gross inside area of the fan outlet expressed in square feet.

      Outlet Velocity (OV)

      The speed at which the air is discharged from the fan outlet.

      Revolutions per Minute (rpm)

      Number of times the fan shaft revolves per minute.

      Saturated Air

      Air containing the maximum amount of water vapor possible at a given temperature and pressure.


      A unit of perceived loudness. The lower the Sone level, the lower the perceived sound. For reference, two (2) Sones are commonly ascribed to the sound level of a common refrigerator.

      Standard Air

      Dry air at 70 F and 29.92 inches of mercury (in. Hg) and weighing 0.075 lbs/ft³.

      Static Efficiency

      Efficiency based on static pressure developed by the fan.
      Formula for Static Efficiency

      Static Pressure (SP)

      The measure of force, exerted by a fan to overcome the resistance of a ventilating system, often expressed in inches of water (in. wg).


      A series of ducts, conduits, elbows, branch piping, grilles etc. designed to guide the flow of air, gas or vapor to and from one or more locations.

      System Curve

      A graphic representation of the pressure versus volume flow, showing the characteristics of a particular system.

      Tip Speed (TS)

      The peripheral speed of the tip of the fan blade. Expressed in feet per minute (fpm).
      Formula for Tip Speed

      Total Efficiency (TE)

      The ratio of the horsepower delivered by the fan (AHP) to horsepower absorbed (BHP). Also refered to as Mechanical Efficiency.
      Formula for Total Efficiency

      Total Pressure (TP)

      The sum of velocity pressure and static pressure.
      Formula for Total Pressure

      Velocity Pressure (VP)

      The measure of force which exists by virtue of the rate of motion of the air only. It is always positive.
      Formula for Velocity Pressure

  • Commercial Fans
    1. Commercial Fans & Dampers

      Currently we do not have any FAQ’s for Commercial Fans & Dampers.
      For further information on Commercial Fans & Dampers please contact us.

  • OEM Solutions
    1. What are the temperature limits for a fan?

      Temperature limits may vary according to fan construction and type.  Please see product specifications or contact our Customer Service department for more information.

    2. What are the recommended installation clearances for motorized impellers?

      Installation clearances can have a significant effect on fan performance.  For motorized impellers, installation clearances should be as tight as fan design and assembly procedures allow.

    3. When selecting an axial fan, how do I determine whether to use an aluminum or GRP impeller?

      Fan performance for axial airfoil impellers is the same regardless of whether the blades are constructed of aluminum or GRP (glass reinforced polypropylene).  Factors affecting the choice of blade material may include operating speed, temperature, airstream composition, spark resistance, weight, UV exposure and cost.

    4. Can I use a speed control with a motorized impeller?

      All of Continental Fan’s motorized impellers can be speed controlled.   Variable frequency drives are a suitable method of speed control for three phase motorized impellers.  For single phase applications, Continental Fan offers a number of control options; available include VSC3 and SCN.

    5. Must I use an inlet cone with my centrifugal impeller?

      Centrifugal impeller performance is based on tests conducted using an inlet cone and a scroll housing.  To maximize performance of a centrifugal impeller, it is recommended than an inlet cone is incorporated in the equipment design.

    6. Must I use a scroll housing with my centrifugal impeller?

      Centrifugal impeller performance is based on tests conducted using an inlet cone and a scroll housing.  Performance will suffer in installations without a scroll housing.  Due to the multitude of possible equipment designs, it is difficult to predict exact losses.

    7. How do I determine whether an axial fan or a centrifugal fan is best suited for my application?

      The airflow and static pressure requirements for your equipment will usually determine which impeller is best suited for your application. In general, axial fans provide high airflow at low static pressure, whereas centrifugal fans develop high static pressure at low airflow.

      Other factors, including space limitations, sound and operating costs may influence the type of fan used. Please contact our Customer Service department if you require assistance.

    8. Can I use two fans to double airflow?

      Two fans installed in parallel (side by side) will double the airflow in a system.

    9. Can I use two fans to double static pressure?

      Two fans installed in series (one after the other) will double the static pressure developed in a system.

    10. Do you sell explosion proof fans?

      There is no such thing as an explosion-proof fan; however a fan can be built in accordance to specific spark resistant classifications to reduce the probability of explosion.  For more information, see the Classifications of Spark Resistant Construction (AMCA Standard 990401-86).

      The chances of explosion may also be minimized by employing an explosion proof motor, or diluting the volatile gas in a system.  Please contact our Customer Service department for assistance.


    11. Can temperature and altitude affect a fan's performance?

      Fan performance will vary with temperature and altitude.  Most fan performance ratings are derived from tests conducted at standard air.  Correction factors can be applied to determine the performance of a fan at actual operating conditions.

    12. What advantages do backward curved airfoil (BCA) impellers have over forward curved (FC) impeller?

      Backward curved airfoil impellers provide the highest efficiency of all centrifugal fan designs. They are quieter and non-overloading, generate significant static pressure and may be used without a scroll housing.

      Forward curved fans are less efficient than BCA fans and may overload a motor. Usually fabricated of lightweight and low cost materials, FC impellers must have a scroll housing and are typically used for airflows at low to moderate static pressures.

    13. In what voltages are motorized impellers available?

      Continental Fan’s motorized impellers are available in a variety of single and three phase voltages, including specialty voltages. Please contact our Customer Service department for assistance.

    14. Can you provide a replacement impeller for a competitor's propeller?

      Yes. Continental Fan’s Selection Software can replicate most competitors’ propellers. The unique modular design with adjustable blade feature allows an infinite combination of impeller diameters and pitch angle settings to match virtually any requested performance.

    15. Are the blades on axial airfoil impellers field adjustable?

      No. The pitch angle on axial airfoil impellers is factory set.

    16. Do I need a capacitor to run a single phase motorized impeller?

      Yes, a capacitor is required. The capacitor creates an out of phase relationship within the motor enabling the motor to rotate.

    17. What information must I provide when ordering an ELTA impeller?

      In order to build an axial airfoil impeller, the following information is required at time of order:

      • Impeller trim diameter
      • Blade material
      • Blade pitch angle
      • Bore size
      • Direction of rotation
      • Airflow direction
      • Motor HP
      • Fan speed
    18. Are AMI, AMR, and AMP motorized axials available in either standard or reverse airflow?

      Yes. Airflow direction must be specified at time of order.

      See also: AMI, AMR, AMP

    19. Are motorized impellers suitable for outdoor installations?

      IP classifications for motor enclosures vary by fan model. Motorized impellers should not be exposed to the elements, but may be used in certain applications if properly protected.

  • Residential Products
    • Residential Products Product Information
    • Duct Boosting
    • Bathroom Ventilation
    • Range Hood Exhaust
    • Clothes Dryer Boosting
    • Backdraft Dampers
    1. How do I read a Performance Data chart?

      To select a fan, one must first determine the airflow and static pressure in a ventilating system.  Airflow is shown on the chart as cubic feet per minute (cfm).  Static pressure is shown on the chart as SP, expressed as inches of water (in. wg).

      The intersection of the required airflow and static pressure will determine the correct model of fan to use in a particular application.  A chart may also provide motor and sound data for a fan.

    2. What is ENERGY STAR?

      ENERGY STAR is a joint program of the U.S.  Environmental Protection Agency and the U.S. Department of Energy, designed to identify and promote energy-efficient products to reduce greenhouse gas emissions.  ENERGY STAR approval ensures that a fan meets or exceeds performance standards and minimizes energy consumption.

      For more information, visit ENERGY STAR online.

    3. What is HVI?

      HVI, also known as the Home Ventilating Institute, is an independent non-profit organization that certifies fan performance characteristics and provides HVAC guidelines for consumers.

      For more information, visit HVI online.

    4. Where is the best place for an in-line fan to be located in a duct run?

      An ideal fan installation will allow for straight duct equivalent to five (5) or more duct diameters to be located before and after the fan.

    5. Can I ventilate multiple rooms (kitchen & bathroom / bathroom & bedroom / multiple bathrooms) with one fan?

      This is possible; however more detailed information would have to be obtained to determine if it is feasible.  Please contact the Customer Service department to discuss.


    1. When is a duct booster fan required?

      A duct booster is commonly used in situations where insufficient heating, cooling or fresh air poses a problem.  In these circumstances, an in-line duct booster fan may be used to compensate for long duct runs or inadequate HVAC systems.  AXC in-line duct fans deliver supplementary air in a quiet, efficient and cost effective manner.

    2. How important is it to have access to an in-line fan after installation?

      Although AXC fans are designed for 20+ years of operation, the fan must be accessible for regular inspection. Maintenance, such as cleaning the exhaust system, should be performed at regular intervals to ensure there is no blockage of airflow.

    3. What types of controls are available to operate an AXC duct booster fan?

      There are several options available to control an AXC in-line duct booster fan: on-off switch, spring wound timer, digital timer, variable speed controller, intrinsic range hood controls.

      Please see residential fan controls for more information.

    1. How much airflow is required for a bathroom?

      HVI recommends ventilation rates based on 8 air changes per hour.  For most bathrooms (less than 100 square feet) this works out to 1 cfm per square foot of area, with a minimum of 50 cfm.

      To calculate the proper ventilation rate for a bathroom larger than 100 square feet, add the cfm requirement for each fixture.

      e.g.:  toilet 50 cfm, shower 50 cfm, bathtub 50 cfm, jetted tub 100 cfm.

      Please note: For proper sizing, the static pressure (SP) needs to be calculated.

    2. Can I ventilate more than one bathroom at a time?

      Ventilating more than one bathroom with a single AXC in-line fan is possible; however there are two issues to consider:

      1. Since air will be exhausted from all bathrooms at once, more heated or cooled air will be removed than may be necessary.
      2. A contactor in the control wiring is necessary to properly control the fan from all locations.
    3. Can an EXT fan be used for duct boosting when space prevents the use of an AXC booster fan?

      EXT fans incorporate the same features and perform the same function as AXC fans, with the added convenience that they can be mounted on an exterior wall.

    4. How many exhaust grilles should be installed in a room?

      When using an AXC in-line duct fan, a single exhaust grille is usually sufficient.  It should be located as close as possible to the shower enclosure.  If there is a whirlpool bath, a second grille over the bath should be considered.  If the room has any dividers in it that would tend to trap air, then each area should be served by a separate grille.

    5. How long should I run a fan after a shower?

      HVI recommends operating an exhaust fan for a minimum of 20 minutes after a shower or bath in order to remove excess moisture from a room.

    6. What type of duct is recommended for bathroom ventilation?

      Consult local building codes before selecting a duct type.  Flexible insulated duct is recommended to minimize condensation from bathrooms or other warm and moist areas, and may be helpful in reducing objectionable fan noise.

    7. Can I exhaust a bathroom fan into an attic?

      No. Local building codes generally require that fans be exhausted directly to the outdoors. Exhausting a bathroom fan into an attic may lead to mold, mildew and possible structural damage to the home.

    8. What types of controls are available to operate an AXC bathroom exhaust fan?

      There are several options available to control an AXC in-line bathroom exhaust fan: on-off switch, spring wound timer, digital timer, variable speed controller, intrinsic range hood controls.

      Please see residential fan controls for more information.

    1. How do I size a range hood exhaust fan?

      The following recommendations follow guidelines published by the Home Ventilating Institute (HVI):

      Wall mounted range hood: 100 cfm per foot of hood width

      e.g.:  a 36” range would require a minimum 300 cfm.

      Island style range hood: 150 cfm per foot of hood width

      e.g.: a 36” range would require a minimum 450 cfm.

    2. How high should my range hood be above my stove?

      Most installations are between 24″ – 30″ from the top of the cook top to the bottom of the hood.  Selecting a range hood 6” wider than the cook top will improve hood efficiency by providing a larger area to better capture cooking impurities.

    3. How often should I clean my grease filters?

      • Aluminum mesh filters should be washed in a dishwasher regularly to remove grease.
      • Carbon filters cannot be cleaned; they must be replaced.
      • Baffle filters, used in professional style range hoods, are designed to operate longer in high grease conditions without loss of performance. These should be cleaned with soap and water whenever surfaces become unsightly.
    4. What type of duct should be used to vent a range hood?

      Metal duct must be used to vent range hoods. Smooth metal duct is recommended over flexible metal duct, which can create turbulence and result in diminished airflow.

      • NEVER use 4″ dryer duct or any plastic duct on a range hood installation.
      • The minimum size duct allowed on most range hoods is equivalent to 6″ round. More powerful hoods require even larger duct sizes up to 10″ round. Consult the specifications for the specific model of hood.
    5. Can I exhaust a range hood into an attic?

      No. A range hood should never be exhausted into wall cavities, ceilings, attics, crawl spaces or garages. Range hoods should always be ducted to the outside of the home.

    6. What types of controls are available to operate an AXC range hood fan?

      There are several options available to control an AXC in-line range hood fan: on-off switch, spring wound timer, digital timer, variable speed controller, intrinsic range hood controls.

      Please see residential fan controls for more information.

    1. When is a clothes dryer booster required?

      A clothes dryer booster may be required if the linear length of a dryer vent system exceeds the maximum length recommended by the dryer manufacturer.  (Note: each 90 degree bend in a system is equivalent to 5 linear feet).  Most dryers will not exhaust adequately when the linear length of a dryer vent system exceeds 15 linear feet.

      In these circumstances, a DVK dryer booster may be used to allow the dryer to operate at peak performance.  Inadequate dryer exhaust may lead to prolonged drying times, excessive energy consumption and needless wear and tear on a dryer.

    2. Is your fan approved for clothes dryer boosting?

      At this time, no standard exists that covers dryer vent boosting; however, UL and CSA are currently developing one for this application. It is recommended that homeowners check with their local building code inspector prior to installing any dryer boost fan.

    3. Can an EXT fan be used for dryer boosting when space prevents the use of a DVK dryer booster fan?

      EXT fans are not recommended for use in a dryer booster application.

    4. How important is it to have access to an in-line fan after installation?

      Although DVK fans are designed for 20+ years of operation, the fan must be accessible for regular inspection. Maintenance, such as cleaning the exhaust system of lint build-up, should be performed at regular intervals to ensure there is no blockage of airflow.

    5. What types of controls are available to operate a DVK dryer booster fan?

      There are several options available to control a DVK dryer booster fan: on-off switch, spring wound timer, current sensor, positive pressure switch and mounted positive pressure switch.

      Please see residential fan controls for more information.

    1. Why use a backdraft damper?

      A backdraft damper prevents unwanted air from entering a duct when a fan is not operating.  This can be very beneficial in keeping outside air from being drawn into a room, or preventing the reversal of indoor air when a number of fans are joined to exhaust through a common duct.  Utilizing a backdraft damper in this manner prevents air that is being exhausted from one area from backing up into other areas connected by the common duct.

    2. How and where do I install a backdraft damper?

      A BDD backdraft damper utilizes a pressure fit for installation inside a duct.  The damper should be located close to the duct discharge to prevent unwanted air from entering that duct.

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