{"product_id":"bard-hvac-mc4002-b-advanced-solid-state-dual-unit-lead-lag-controller-with-enhanced-alarm-board","title":"Bard HVAC MC4002-B Advanced Solid State Dual Unit Lead\/Lag Controller with Enhanced Alarm Board","description":"\u003cp\u003eThe Bard MC4002-B is an advanced solid-state dual-unit lead\/lag controller engineered for Bard HVAC wall-mount systems that require reliable redundancy control, staged operation, equipment rotation, and alarm monitoring.  Designed to manage two connected HVAC units, it supports multi-stage cooling and heating, automatic lead\/lag rotation to balance runtime, and selectable sequencing to help maintain stable temperature control in commercial, industrial, telecom, modular, and equipment-room environments.\u003c\/p\u003e\n\u003cp\u003eThe integrated enhanced alarm board adds critical system visibility by monitoring power loss, refrigerant lockout, high and low temperature conditions, controller failure, and environmental thresholds.  This helps maintenance teams identify faults quickly, reduce downtime, and protect cooling equipment in applications where continuous HVAC performance is essential.  The MC4002-B directly replaces the Bard MC4000-B control with alarm and the MC4001-B alarm board, making it a dependable upgrade or service replacement for compatible Bard lead\/lag control systems.\u003c\/p\u003e\n\u003cp\u003eBuilt with solid-state control logic, 24VAC HVAC relay outputs, programmable memory retention, and network monitoring capability, the Bard MC4002-B provides a practical control solution for facilities that depend on coordinated dual-unit operation, alarm reporting, and long-term HVAC system protection.\u003cbr\u003e \u003c\/p\u003e\n\u003ch6\u003e\n\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003cbr\u003e \u003c\/h6\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eWhat is the Bard MC4002-B used for?\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThe Bard MC4002-B is used to control two Bard HVAC wall-mount units in a lead\/lag setup.  It helps stage system operation, rotate equipment runtime, and provide alarm monitoring for critical cooling applications.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eDoes the Bard MC4002-B control two HVAC units?\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eYes.  The MC4002-B is designed for dual-unit HVAC control and supports coordinated operation between two Bard wall-mount air conditioning systems.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eWhat does lead\/lag control mean?\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eLead\/lag control allows one HVAC unit to operate as the primary unit while the second unit acts as a backup or support unit.  The controller can rotate operation to help balance runtime and reduce wear on a single unit.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eWhat does the enhanced alarm board do?\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThe enhanced alarm board monitors important system conditions such as power loss, refrigerant lockout, high or low temperature events, controller failure, and environmental alarms.  This helps facility teams respond faster to HVAC problems.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eIs the Bard MC4002-B a replacement part?\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eYes.  The Bard MC4002-B directly replaces the Bard MC4000-B control with alarm and the MC4001-B alarm board.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eWhere is the Bard MC4002-B commonly used?\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThe MC4002-B is commonly used in telecom shelters, modular buildings, equipment rooms, mechanical rooms, and commercial HVAC installations where continuous cooling and system redundancy are important.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eDoes the MC4002-B help reduce equipment wear?\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eYes.  By rotating lead and lag operation between two HVAC units, the controller helps balance runtime across equipment, which can support longer service life and more even system usage.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eWhat voltage does the Bard MC4002-B use for HVAC relay outputs?\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThe Bard MC4002-B uses 24VAC HVAC relay outputs for compatible control applications.\u003c\/p\u003e","brand":"Bard","offers":[{"title":"Default Title","offer_id":52841382248735,"sku":null,"price":799.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0915\/4776\/2975\/files\/Bard-HVAC-MC4002-B-Advanced-Solid-State-Dual-Unit-Lead-Lag-Controller-with-Enhanced-Alarm-Board.png?v=1788289071","url":"https:\/\/www.nraparts.com\/products\/bard-hvac-mc4002-b-advanced-solid-state-dual-unit-lead-lag-controller-with-enhanced-alarm-board","provider":"NRA PARTS","version":"1.0","type":"link"}