Liebert AC4 and AC8 Controllers


Liebert AC4 and AC8 Controllers

Automatic Switching for Precision Cooling Systems

Liebert AC4 and AC8 autochangeover controllers are ideal for coordinated control of systems with redundant equipment, such as multiple environmental units or pumps. When the controller detects an alarm in an operating device, a standby device is enabled and the device in alarm is either disabled or left operating as configured.

Liebert Controllers monitor running and stand-by environmental units for proper operation, switching operation to a redundant unit in the event of a problem. The controllers will also balance the runtime of environmental systems to ensure even component wear and long system life.

  • Liebert AC4 is a four device controller with LCD display and terminal interface. Powered by 24VAC.
  • Liebert AC8 is an eight device controller with Liebert SiteScan Web compatibility and modem interface. Powered by 120VAC.
  • Autochangeover for precision cooling units
  • Balances system runtime for even component wear
  • Controls up to 8 cooling systems


  • User-friendly LCD interface employs clear, simplified instructions for programming and configuration, eliminating the chances of operator error.  
  • Can interface with anything that closes an electrical contact.  
  • Custom configuration for specific applications and equipment.  

Higher Availability  

  • Provides automatic centralized control of computer room critical equipment, simplifying emergency switching and unit testing.
  • When the module recognizes an alarm condition, emergency switching capability enables it to automatically switch to a stand-by unit.  
  • Alarm logs with time and date stamp.  

Lowest Total Cost Of Ownership  

  • For longer cooling system life, the controllers can balance the runtime of all connected air units according to a user-defined schedule.  

Ideally Suited For  

  • Redundant cooling units  
  • Redundant pumps  
  • Redundant dampers
  • Redundant fans

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Contact your local Liebert NA Representative at your location.

Monitoring Products
Contact our Liebert NA support department about your Liebert monitoring software and hardware.

Sales, Service, and Support
Outside the US: +800-1155-4499

Monitoring Products
Contact our Liebert support department about your monitoring software and hardware.

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