Bard MC4002-B Advanced Solid State Dual Unit Lead/Lag Controller with Enhanced Alarm Board
The Bard MC4002-B Advanced Solid State Dual Unit Lead/Lag Controller is designed to manage and sequence two connected HVAC units, providing reliable temperature control and balanced runtime for critical environments such as telecom shelters, equipment rooms, and commercial facilities.
The MC4002 provides two stages of cooling control for each connected air conditioner, making it ideal for systems with or without economizers and for systems using 2-stage or dual compressors. The second stage of cooling ensures proper operation when economizers are installed or when multi-stage compressors are used.
With the addition of a simple 2-wire humidity controller, the MC4002 can also provide an electric reheat dehumidification circuit. The controller may also be configured for heat pump applications (note: the electric reheat dehumidification feature is not available when configured for heat pumps).
The MC4002 is a fully functional and highly configurable controller, available either as a base controller or factory-equipped with optional alarm relay boards that provide expanded alarm monitoring capabilities. For installations that begin with the base controller, alarm relay boards and communication options can be easily added later through a simple snap-in upgrade and plug-in communication cable connection.
The controller utilizes Form C dry contact alarm relays (NO and NC), allowing integration with virtually any building alarm or monitoring protocol. All alarm conditions are individually indicated on the front panel, along with status indicators showing active heating or cooling stages and which unit is currently operating as the lead unit.
A built-in digital display shows building temperature and provides an easy interface for configuration and programming of the controller.
Key Features
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Controls two HVAC units in automatic lead/lag rotation
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Two stages of cooling control per air conditioner
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Compatible with economizer systems
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Supports 2-stage or dual compressor systems
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Optional electric reheat dehumidification with humidity controller
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Configurable for heat pump applications
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Optional alarm relay boards and Ethernet communication
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Form C dry contact alarm relays (NO/NC) for flexible monitoring integration
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Front panel indicators for alarms, active stages, and lead unit status
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Digital display for temperature monitoring and programming
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Upgradeable design with snap-in alarm boards and communication modules
