Liebert® AC4 Controller

This product is discontinued.

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.


Autochanger for up to eight cooling unitsLCD interface and a terminal interface, as well as interface to Liebert® SiteScan™ WebAdjustable 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 changeoverHigh and low analog (temperature) alarmsAnalog controlled staging of devices (temperature staging of units)Power failure overrideTwo Form C control relays activated by any digital or analog inputPaging for up to four numbersPreconfigured onboard modemBattery backupUser interface via RS232 or modem connection


Ensures high availability of cooling through automatic centralized control of computer room critical equipmentSimpilfies emergency switching and unit testingBalances system runtime to reduce cooling unit wear and tearUser-friendly interface makes it easy to programInterfaces with any device that closes an electrical contact

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