Johnson Controls A350RS-1 Control

The Johnson Controls A350RS-1 is a professional-grade electronic temperature reset control designed for precise regulation of HVAC heating systems. As a direct replacement for the A350RT-1, this model significantly simplifies installation by including the necessary A99BB-300 supply sensor and A99BC-25 master sensor in the package. Operating on a 24Vac power supply, the unit features a high-performance SPST normally open relay and facilitates an adjustable differential of 1 to 30 degrees F, allowing technicians to fine-tune system response and cycle rates to match specific building heat loss characteristics.

Engineered for versatility, the A350RS-1 supports a broad setpoint range of -30 to 150 degrees F and a master reset setpoint adjustment from 40 to 70 degrees F. This level of control enables the electronic heating system 350 to dynamically shift the supply water or air temperature based on outdoor conditions, maximizing energy efficiency. Its modular NEMA 1 high-impact plastic enclosure ensures compatibility with other System 350 expansion modules, such as S350 stage modules or D350 digital displays, providing a scalable solution for complex contractor requirements.

Key Benefits

• Complete Control Package: Includes both the supply and master A99 thermal sensors, eliminating the need for separate sourcing and ensuring immediate compatibility.
• Optimized Energy Efficiency: The adjustable reset ratio (1:5 to 3:1) allows the system to lower supply temperatures during milder weather, reducing fuel consumption and equipment wear.
• Flexible System Integration: Features a modular design that supports DIN rail or surface mounting and integrates seamlessly with plug-in accessory modules for multi-stage applications.
• Broad Operating Range: Wide setpoint and differential ranges accommodate diverse heating environments, from standard residential boilers to industrial process heating.

Common Questions

How does it differ from the A350RT-1?
The A350RS-1 is the identical functional control unit but comes bundled with the A99BB-300 and A99BC-25 sensors. The RT-1 model was sold as the control module only.

Can I use this for cooling applications?
While primarily designed as a heating system reset control with a normally open relay, the System 350 line includes other modules specifically for cooling. Professional installers should verify the specific wiring logic for their application needs.

What is the maximum distance for the sensors?
The included A99 sensors utilize a PTC silicon element. While they come with standard lead lengths, they can be extended using 22 AWG twisted pair wire, though technicians should account for total loop resistance to maintain calibration accuracy.

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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.