Like all compressors made by Andover Protection Systems, LLC, APS’ Division/Zone 2 compressors are all hermetically sealed for two reasons:

  • to protect the environment from any risk of sparks escaping from the motors and other inner workings and
  • to protect the compressors from the environment—corrosion, dust, water and other potentially-harmful elements

In addition, to make them safe for frequent, or even constant, presence of hazardous-gases or dusts in potentially explosive concentrations, APS’ Division/Zone 2 compressors are further protected by enclosing the electrical connections inside in an explosion-proof enclosure (virtually the same as a flame-proof enclosure) to assure that:

  • hazardous gases and dusts cannot reach the electrical connections
  • if harmful gases or dusts manage to enter the housing and explode (for instance, when someone opens the enclosure in the hazardous environment and traps the explosive gas or dust inside), the enclosure will contain the explosion and will not let it escape into the atmosphere

Access for wiring is gained through the end of the enclosure by removing the plug.  At four inches (10 cm) in diameter, the opening is large enough to use one’s hand to wire up the connections.  All sizes of APS compressors from the smallest fractional-horsepower models to the largest—about 30 horsepower—offer the same easy access for wiring.

The wires enter the enclosure through a male-threaded nipple to which the installer can attach any appropriate connecting and sealing device.  In many cases, the customer can specify the direction toward which he/she wants the nipple to extend (12 o’clock, 4 o’clock, and the like) to make connecting the wires, seals and conduit as easy as possible

All APS compressors are available in the following Division/Zone configurations:

  • Class I  Groups B, C and D  Division/Zone 2
  • Class I  Groups C and D  Division/Zone 2
  • Class I  Group D  Division/Zone 2
  • Class II  Groups E, F and G  Division/Zone 2
  • Class II  Groups F and G  Division/Zone 2
  • Class II  Groups G  Division/Zone 2
  • Class III Division/Zone 2

More than 800 models, ALL recognized by Underwriters Laboratories, Inc. (UL)
Easier to obtain third-party inspectors’ approvals and listings (such as UL, ETL, and CSA) and local governmental inspectors, since compressors already have UL approval (no open compressors are so recognized).

  • Easy wiring
  • Adaptable design to fit users’ configuration
  • Many electrical configurations
  • In some applications, they can eliminate the need for a separate NEMA 7 box
  • Compatible with most refrigerants (HFCs, HCFCs, and CFCs)
  • Models for low, medium and high-temperature applications
  • Protect electrical connections in corrosive, wet, and other harsh environments
  • Make construction and installation of air-conditioning and refrigerating systems faster, easier and less expensive while increasing the flexibility of the designs.  In fact, in many cases the APS compressors are so compact that the OEM can use essentially the same design as it would for ordinary (non- hazardous) versions of their chiller or other product

Using APS compressors eliminates the problems of open compressors:

  • The possibility of static electricity forming on belts in hazardous environments
  • The belts themselves corroding, wearing, collecting dust, or slipping
  • Leaking refrigerants since all connections to APS compressors can be brazed, and offer the option of non-leaking Rotalok connections as well.
  • Quieter
  • Smaller footprint
  • Lower weight
  • Far less vibration
  • Installed in dozens of countries around the world

Why use APS compressors?

No other compressors are tested and expressly recognized by Underwriters Laboratories as safe for use in either Division/Zone 1 or Division/Zone 2 locations in any class or group.
When you assemble a complete product APS’ proven designs and UL’s recognitions assure that the compressor is safe for the indicated environments and therefore that part of the unit will not have to be independently tested to verify its safety, thereby reducing the costs of UL listing of your products.

The threaded plug on the 3 1 /2 ” (8.9 cm) ID enclosure makes wiring, and even rewiring, easy because a technician can fit his/her hand inside to work on the wiring.

APS protects all its compressors with resistant coatings to assure long life in corrosive environments.

APS offers scroll and reciprocating compressors with POE, mineral and other types of oils in capacities from 1/20 Horsepower to 30 HP and for low, medium and high-temperature applications.  To assure that we provide you the best model for your purposes, please complete and return the data form:  Click Here

  • For an overview of APS’s Hazardous-Duty Refrigeration and Air-Conditioning Compressors,  Click here.
  • If you have a specific application in mind, please complete our Project Data Form for Hazardous-Duty Compressors. An engineer will then prepare a proposal with our recommended solution.
  • If you have questions about how hazardous/explosive areas are classified, Click here.
  • For an overview of APS’s Air-Cleaning BlowersTM (ACBs) that blow and clean air in hazardous areas, Click here.
  • All APS products retain their UL recognitions in all applications when modified for hazardous (“explosion-proof”) environments. Click here
  • If you have more general questions or comments, please use our Contact APS Form.