Keeping your ventilation fans in top working condition

By Steve Ewing

In today’s modern poultry houses, all ventilation provided to the birds is accomplished by using power ventilation fans. These fans provide all the required cfm(s) of fresh air to the birds. They also provide the windspeed and pressure for evaporative cooling, removing btu’s of heat and CO2 from the birds, and removing humidity from the inside of the house and in the litter. For these reasons it is critical to keep these fans in top working condition.
External photo of poultry house showing ventilation fans

Let’s talk about a few points to consider when evaluating your fans.

  • Shutters and cones are engineered to allow maximum air flow through the fan. Whether the fan has louvered or butterfly shutters, ensure that all the components are present and move and seal properly. Shutters that don’t open properly or cones that are bent will cause a reduction in the amount of air that a fan can efficiently move. Dry clean or wash shutters and cones periodically to ensure surfaces are smooth. Replace missing louvers to ensure air is being pulled into the house through the intended inlet.

    Ventilation fan shutters before and after photos

  • Belts and pulleys are the most common insufficiency observed in the field. The manufacturer sizes these components to achieve a target gear ratio and airflow for a specific fan.

    Ventilation fans belts and pulleys diagram

    Replacing a belt with the proper size is critical in maintaining the stated airflow. A properly fitted belt should ride in the pulley with +/- 1/8” of the belt visible outside of the pulley. This allows the belt to run in the pulley with maximum contact creating the desired gear ratio. Any time a belt is observed running below the edge of the pulley, as much as 10% of the fan’s capability is lost through gear ratio or slippage, which means the belt and /or pulley should be replaced.
  • Inspect the bearings and tensioners. A dry bearing creates friction and robs the fan of its efficiency. It also increases the likelihood that that fan will fail, potentially leaving the birds short on ventilation. Follow the manufacturer’s recommendation on grease type and intervals for best results. Inspect and replace tensioners as needed. A worn belt tensioner can allow belts to slip reducing the life of the belt and pulley.
  • The motor is the heart of the fan. Inspect all the electrical connections, from the breaker to the receptacle, providing power to the motor. Ensure all connections are tight and free of corrosion. Either of these will cause voltage drop and can build heat in the motor that will surely lead to shortened life. Monitor the circuit by utilizing breaker spots on the breaker. These will indicate heat on the breaker, which usually means there is an increased load on the circuit caused from a weak or failing breaker due to poor connection.

    Ventilation fans circuit breaker switches

    Most fan motors utilize capacitors to get the fan up to operating speed quicker. If a motor fails, always check the capacitor first before replacing the motor. This is a replaceable part and less expensive than replacing the entire motor. Dry cleaning the frame of the motor when the fan is not operating will allow maximum airflow through the motor, further reducing heat stress.

After you have made the initial purchase of a fan, each revolution of the blade is made possible by watts of electricity that you are paying for. Keeping the points checked as we have just discussed will ensure that the fan will perform at the cfm per watt rating that it was intended to. Protect your investment and provide the best environment possible for your birds.

About the Author

Steve Ewing

Territory Manager
MWI Animal Health
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