Specifying a Freeaire System
  1. Consult the Catalog. Refer to Catalog of Products and Catalog of Options to see the product specifications and what options and accessories that you might need.
  2. Fill out a Worksheet. Fill out a Worksheet for each installation and send it to us. This will help you to decide what is needed, to know how much it will cost and to estimate how much energy savings to expect. It will give us something to look at in order to help you decide if you are getting what you need.
  3. Send in Your Order. Go to Contact Us to tell us exactly what you want, how you want to have it shipped and how you are going to pay.

Basic Freeaire Systems. Every Freeaire System includes a Basic System, consisting of a model 2001 Cooler Controller, two sensors, and a Circ circulating fan.

Circ Fans The number of circulating fans you need depends on the size and configuration of the box, but a Circ fan for each 5000 cubic feet is a good rule of thumb. The Basic Freeaire's single Circ fan should handle a walk-in cooler up to about 8' x 12' x 50', when centrally located and airflow is not blocked by partitions or large stacks of product. Narrow, confined, and L-shaped spaces may need additional Circ fans to maintain good air circulation throughout.

Outside Air Packages. The number of intake fans is always balanced by an equal number of exhaust fans to keep the air pressure within the walk-in just slightly pressurized. This is why the Outside Air Package components are not sold separately. Most Freeaire systems using outside air in spaces under 5000 cubic feet need use only a single Outside Air Package. A good rule of thumb is a single Outside Air Package for each 5000 cubic feet or each 5 horsepower of compressors. Actually, a single Outside Air Package will work in any size cooler. It's just that the 500 cfm of cold outside air at a given temperature difference doesn't contain enough cooling power to handle a large cooling load without help from the compressor system. When the load gets large enough over a long enough period of time, it becomes economical to add a second package. There is a lot of room for error in specifying the number of Outside Air Packages for three reasons:

  1. The Cooler Controller's differential thermostat allows simultaneous operation of each of the two refrigeration systems, so the compressor system is always available to help out if the outside air fans can't bring in enough outside air to handle the cooling load at any time.
  2. The cooling capacity and efficiency of an Outside Air system rises rapidly as the outside air temperature falls, so even a drastically undersized system can handle all the cooling needs of a walk-in cooler if the outside temperature is low enough. If outside air can't handle the entire refrigeration load by itself when the outside air is only 4° cooler than the air inside the walk-in, then perhaps it can when the outside temperature is 6° or 8° cooler. Sooner or later, the cooling capacity of the outside air becomes so great that the compressor system won't operate at all.
  3. A large Outside Air system does not make the walk-in any colder than a smaller one. It just means the outside air fan needs to operate less of the time to maintain the proper temperature inside the walk-in.

Temperature Sensors: Make sure you order an outside temperature sensor with the first Outside Air Package, but not with extra packages. If any standard sensor wire is too short, be sure to order a custom length.

Options and Accessories. Some of the things, like duct pipe and relays, may be available locally in your area and don't include shipping from Vermont. If you find your own sources for these things, make sure they are equivalent to what we sell.

Specifying Planning Installing Wiring Cooler Controller Commissioning & Troubleshooting Maintaining