Honeywell 301-EM-US3 Controller

The Honeywell 301-EM-US3 Controller is a central processing hub designed for mechanical room refrigerant gas detection and ventilation control. Built for wall-mount applications, this unit effectively manages up to 20 remote sensors via Modbus RTU communication, ensuring comprehensive coverage of large mechanical spaces. It serves as the direct replacement for legacy models M-512426, VA301EM, and VA301EM-20, facilitating a seamless upgrade path for aging HVACR safety systems. The controller features four integrated DPDT programmable relays for activating exhaust fans, louvers, or remote alarms based on user-defined setpoints. Its internal data logging capabilities and daylight savings time functionality support compliance with ASHRAE 15 and B52 safety standards. This Honeywell refrigerant monitor provides a localized visual display of gas concentrations, allowing technicians to verify system status and silence alarms directly at the panel without requiring external diagnostic tools.

• Multi-Sensor Integration: Supports a network of up to 20 remote sensors for wide-area refrigerant monitoring.
• Legacy Compatibility: Engineered as a drop-in replacement for the VA301EM series with standardized mounting and wiring.
• Robust Control Logic: Includes four relays to automate ventilation sequences and meet building code safety requirements.
• Digital Communication: Utilizes RS-485 Modbus connectivity for stable data transmission between the controller and remote sensing heads.

Common Questions

Is the 301-EM-US3 compatible with older VA301EM installations?
Yes, this unit is the designated successor for VA301EM and M-512426 controllers, utilizing the same footprint and wiring architecture for efficient field retrofits.

Does this controller support Modbus communication?
The Honeywell 301-EM-US3 communicates with remote sensors via Modbus, allowing for simplified daisy-chain wiring and increased data reliability compared to analog systems.

Can I use this to meet ASHRAE 15 requirements?
This controller is designed specifically to assist facilities in meeting ASHRAE 15 and B52 standards by providing the necessary alarm logic and ventilation control outputs for mechanical rooms.

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Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.