Air Curtain FAQ & Troubleshooting Guide


Operation & Performance

Why Do Mars Air Curtains Have Adjustable Air Directional Vanes At The Air Outlet?

The air directional vanes in the discharge nozzle can be positioned inward or outward. This design feature provides the capability to compensate for drafts, wind loads, and necessary adjustments to effectively repel flying insects, dust, fumes, odors, and other wind borne contaminants. If the air curtain is mounted internally in a building for environmental separation (i.e. separating a manufacturing area from a clean work area) or over a refrigerated room door for temperature control, the directional vanes should be pointed straight down.

What Happens To The Air When It Hits The Ground?

As the air reaches the floor, it will divide, sending the air inward and outward simultaneously and causing a draft both ways at the floor line. When using an air curtain for insect and dust control, the directional vanes in the air outlet nozzle should be directed outward not only to repel the insects and dust but to also allow the least amount of air to come inward when hitting the floor. If mounted on the outside of the doorway and used for the purpose of holding in air conditioning when the door is open, the directional vanes should be slanted slightly outward. Mounted on the inside of a cooler, the vanes should be turned slightly into the refrigerated room. It is important to remember that when an air curtain is used for refrigeration or climate control, it is absolutely necessary to adjust the velocity control so the air stream gently hits the floor with the least amount of vacuum reaction, thus pulling the air out of the protected room and defeating the intended function of the air curtain and causes icing on the floor.

Accessories & Options

How to choose which heating option is right for me?

Many of the MARS air curtains are available in both heated and unheated versions. In most cases, Mars offers four different heating methods: steam or hot water coil, electric and indirect gas-fired. Each offers its own distinct benefits and features.

Q     The first question is: do I really need a heated air curtain?
A     The answer is maybe not. Your Mars Air Door effectively creates an efficient insulation barrier between two environments. It's approximately 80% - 90% efficient. It does so by creating a stiff blast of air blowing down from the unit towards the floor. This blast of air create an invisible barrier separating the two environments.

If you have people working near or walking through this moving air, they may feel a breeze. This could cause a wind chill effect, similar to the cooling effects of a blowing fan during the summer. Adding a heated air curtain unit will minimize this effect and make for a comfortable and more productive work place for your employees and customers.

Should your facility be located in a cold weather environment creating significant temperature differences between the outside versus the inside temperature, a Mars Air Door heated unit will significantly improve the work environment comfort level and help maintain consistent temperature control. In addition, it will reduce overall utility and maintenance costs by providing a more constant inside temperature.


Q     OK, that makes sense. So I've decided that I need a heated unit. Which one do I choose; gas, electric, hot water or steam?
A     The general rule of thumb is to choose the same type of heat used to heat your facility, however, there may be some exceptions. For example: if your facility is steam heated, but the connection to the steam lines is too far, inconvenient or expensive, it may be more feasible to choose gas or electric.

To ensure that we install the correct heating method and proper heating outputs for you, we highly recommend consulting with your friendly Mars factory representatives first for proper selection.

What Is A Door Limit Switch And When Is It Used?

A door limit switch activates the air curtain when a door is opened and turns it off when the door is closed. When the door is shut, the switch’s contacts are held open. When the door is opened, the contacts are closed, thereby turning the air curtain on. Generally, a door limit switch is installed when a door is intermittently in use, such as over receiving and cold storage doorways. It is preferable to allow the air curtain to operate continuously and not to install a door limit switch if there is heavy in and out traffic. When using a door limit switch a motor control panel is recommended for all three-phase motors and single phase motors with combined capacities of more than 1HP.

Can A Limit Switch Be Used On All Types Of Doors?

Yes. Our combination door limit switch is both a roller and plunger all-in-one and can be used on most hinged, rolling, and sliding doors. We have additional switches available for larger doors, industrial settings, or clean, almost invisible applications.

What Is A Motor Control Panel And When Is It Used?

A motor control panel is an enclosure containing the equipment to start electric motors, usually mounted on the wall near the air curtain to be controlled. The equipment consists of motor starters, a transformer for the control circuit, terminal blocks, and other components to meet specific requirements. It is also used to start, stop, and protect the motors in the air curtains. Motor control panels are available as an option and can be manufactured to meet any requirement. All electric heated models contain a motor control panel as standard equipment. All Mars motor control panels are U.L. Listed.

Can Filters Be Used In Front Of Louvers?

Yes. Filters can be used in conjunction with or instead of louvers. Filters are used when there is an excessive amount of dust and dirt in the air. All Mars NSF Certified models feature a washable aluminum filter as standard. Filters are also supplied with the LPN25-F, LPN28-F and LPN30-F service window models.

Which Mars Air Curtains Contain Stainless Steel Blower Wheels?

The EP models have stainless steel fans. Our other models, and all heated models, have galvanized steel fans, except the LoPro Series models which are aluminum.


Does Mars Air Doors Advertise Nationally?

Yes, a heavy advertising program has always been aimed at the user. Our advertising has appeared in numerous food, beverage, and supermarkets publications as well as heating, air conditioning, and refrigeration trade journals, and engineering publications. We are also in specialized publications such as: Thomas Register, ARCAT, and Auto Quotes automated catalog services.

What Are The Main Advantages Of The Mars Air Doors Brand Air Curtains?
  • All housings are one piece, as specified by architects. Some are used in tandem for larger sized doors.
  • C, CH, CHS, models have PolyMars housings. PolyMars housings are advantageous for various climates and décor.
  • A variety of over 250 compact models to fit any size doorway in unheated and electric, gas, steam and hot water-heated models.
  • Heavy duty totally enclosed motors. All other components are of the highest quality to provide long life and trouble-free service. Two speed motors available as an option. Three speed ½ HP motors are standard equipment on all models. Three-phase motors in single-speed only.
  • All motors have a one second motor start to full capacity operation.
  • Easy to install and maintain by removing two wing nuts and quickly lifting out the entire motor/fan assembly. Mars originated this "One Man installation" design.
  • Designed to fit over doorways up to 12’ wide. Can be used in multiples for wider openings.
  • Motor/fan assemblies are interchangeable in various models.
  • Contain air directional and velocity controls for field adjustments. This is imperative for climate control and over refrigeration doorways.
  • Five year parts guarantee on all models except heated, WindGuard models, and Wind Stopping models, which have an eighteen month guarantee. These are the longest guarantees in our industry.
  • Freight paid to destination or port of embarkation anywhere within the continental United States (gas-heated and WindGuard models excluded).
  • All unheated and electric heated air curtains are UL Listed. Unheated air curtains are also C.U.L. Listed and/or Canadian Standards Association Certified. Gas heated air curtains consist of a UL Listed air curtain equipped with an American Gas Association design-certified duct furnace.