Delivering complex mission-critical integrated HVAC and Power Solutions to hundreds of businesses


Liebert AC4 Controller

Autochangeover controllers are ideal for coordinated control of systems with redundant data center infrastructure 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.

Product Features

Autochanger for up to eight cooling units
LCD interface and a terminal interface, as well as interface to
Liebert SiteScan Web
Adjustable auto-cycle interval for automaticchangeover (up to 99 days)
Adjustable alarm delay before control after alarm (up to 99 minutes)
Device in alarm can be selected to disable (shutdown) or remain enabled (continue running) after changeover
High and low analog (temperature) alarms
Analog controlled staging of devices (temperature staging of units)
Power failure override
Two Form C control relays activated by any digital or analog input
Paging for up to four numbers
Preconfigured onboard modem
Battery backup
User interface via RS232 or modem connection

Product Benefits

Ensures high availability of cooling through automatic centralized control of computer room critical equipment
Simpilfies emergency switching and unit testing
Balances system runtime to reduce cooling unit wear and tear
User-friendly interface makes it easy to program
Interfaces with any device that closes an electrical contact




Winning Together

Computer Environment believes it is the responsibility of a business to use its resources and influence to make a positive impact. Over the last 40 years, Computer Environment has evolved as the trusted resource in critical environment infrastructure and systems in the Mid-South . Our industry experts in air, power, UPS, and other system support solutions work hand-in-hand with engineers and contractors – both mechanical and electrical to deliver complex mission-critical integrated HVAC and Power Solutions to hundreds of businesses. Ensuring a high level of satisfaction among our customers and partners with our “winning together” attitude is a core value at Computer Environment.

Unrivalled Support

We are committed to your continued satisfaction. From product selection to problem resolution, here are the resources you need to quickly and easily answer all of your questions. Access free downloads and the latest news and industry alerts related to your mission critical operations. Find important product documentation anytime of the day. And, provide us feedback so that we can continue to improve your access to the information you need, when you need it.

HVAC and UPS Service (24x7)

Liebert Services – (800) 543-2378 (Liebert)