Johnson Controls A421AET-01 Temperature Control
The Johnson Controls A421AET-01 is a line-voltage electronic temperature control designed for versatile HVACR applications, providing a reliable alternative to traditional electromechanical thermostats. Operating on 120/240 VAC, this SPDT controller features a broad setpoint range of -40 to 212°F, making it ideal for both refrigeration and heating logic. Built with a NEMA 1 enclosure for surface mounting, the unit includes a high-visibility front panel LCD for real-time monitoring and parameter adjustment. The A421 series utilizes a Type A99 PTC silicone sensor (9.75-foot lead included) to ensure high-accuracy feedback. Field technicians appreciate the adjustable off-cycle defrost and anti-short cycle delay, which protect compressor longevity. Whether you are managing walk-in coolers or condenser fan cycling, the A421AET-01 (identical to the A421AET-01C) provides precise digital temperature control with programmable heating and cooling modes to suit specific job site requirements.
- Wide Operating Range: Covers -40 to 212°F (-40 to 100°C), supporting diverse HVACR refrigeration control needs.
- Field-Adjustable Logic: Easily toggle between heating and cooling modes with adjustable differential and sensor offset calibration.
- Universal Voltage: Auto-detects 120/240 VAC power supply, reducing the number of SKUs required on the service truck.
- System Protection: Integrated anti-short cycle delay prevents rapid compressor cycling and mechanical wear.
- Touch-Safe Design: The NEMA 1 high-impact plastic housing keeps internal wiring secure while providing easy access to terminal blocks.
Common Questions
Can the A421AET-01 be used for both heating and cooling?
Yes. The SPDT relay output and programmable menu allow you to configure the device for either "Cut-in High" (cooling) or "Cut-in Low" (heating) applications.
What is the maximum sensor lead length supported?
While it includes a 9-foot lead, the A99 sensor can be extended up to 300 feet using 18 AWG shielded cable, provided you calibrate for sensor resistance in the settings.
Is this model compatible with 24V systems?
No, the A421AET-01 is a line-voltage model. For low-voltage 24V applications, a different sub-model within the A421 Series must be selected.
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.
Original: $185.99
-65%$185.99
$65.10Johnson Controls A421AET-01 Temperature Control
The Johnson Controls A421AET-01 is a line-voltage electronic temperature control designed for versatile HVACR applications, providing a reliable alternative to traditional electromechanical thermostats. Operating on 120/240 VAC, this SPDT controller features a broad setpoint range of -40 to 212°F, making it ideal for both refrigeration and heating logic. Built with a NEMA 1 enclosure for surface mounting, the unit includes a high-visibility front panel LCD for real-time monitoring and parameter adjustment. The A421 series utilizes a Type A99 PTC silicone sensor (9.75-foot lead included) to ensure high-accuracy feedback. Field technicians appreciate the adjustable off-cycle defrost and anti-short cycle delay, which protect compressor longevity. Whether you are managing walk-in coolers or condenser fan cycling, the A421AET-01 (identical to the A421AET-01C) provides precise digital temperature control with programmable heating and cooling modes to suit specific job site requirements.
- Wide Operating Range: Covers -40 to 212°F (-40 to 100°C), supporting diverse HVACR refrigeration control needs.
- Field-Adjustable Logic: Easily toggle between heating and cooling modes with adjustable differential and sensor offset calibration.
- Universal Voltage: Auto-detects 120/240 VAC power supply, reducing the number of SKUs required on the service truck.
- System Protection: Integrated anti-short cycle delay prevents rapid compressor cycling and mechanical wear.
- Touch-Safe Design: The NEMA 1 high-impact plastic housing keeps internal wiring secure while providing easy access to terminal blocks.
Common Questions
Can the A421AET-01 be used for both heating and cooling?
Yes. The SPDT relay output and programmable menu allow you to configure the device for either "Cut-in High" (cooling) or "Cut-in Low" (heating) applications.
What is the maximum sensor lead length supported?
While it includes a 9-foot lead, the A99 sensor can be extended up to 300 feet using 18 AWG shielded cable, provided you calibrate for sensor resistance in the settings.
Is this model compatible with 24V systems?
No, the A421AET-01 is a line-voltage model. For low-voltage 24V applications, a different sub-model within the A421 Series must be selected.
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.
Product Information
Product Information
Shipping & Returns
Shipping & Returns
Description
The Johnson Controls A421AET-01 is a line-voltage electronic temperature control designed for versatile HVACR applications, providing a reliable alternative to traditional electromechanical thermostats. Operating on 120/240 VAC, this SPDT controller features a broad setpoint range of -40 to 212°F, making it ideal for both refrigeration and heating logic. Built with a NEMA 1 enclosure for surface mounting, the unit includes a high-visibility front panel LCD for real-time monitoring and parameter adjustment. The A421 series utilizes a Type A99 PTC silicone sensor (9.75-foot lead included) to ensure high-accuracy feedback. Field technicians appreciate the adjustable off-cycle defrost and anti-short cycle delay, which protect compressor longevity. Whether you are managing walk-in coolers or condenser fan cycling, the A421AET-01 (identical to the A421AET-01C) provides precise digital temperature control with programmable heating and cooling modes to suit specific job site requirements.
- Wide Operating Range: Covers -40 to 212°F (-40 to 100°C), supporting diverse HVACR refrigeration control needs.
- Field-Adjustable Logic: Easily toggle between heating and cooling modes with adjustable differential and sensor offset calibration.
- Universal Voltage: Auto-detects 120/240 VAC power supply, reducing the number of SKUs required on the service truck.
- System Protection: Integrated anti-short cycle delay prevents rapid compressor cycling and mechanical wear.
- Touch-Safe Design: The NEMA 1 high-impact plastic housing keeps internal wiring secure while providing easy access to terminal blocks.
Common Questions
Can the A421AET-01 be used for both heating and cooling?
Yes. The SPDT relay output and programmable menu allow you to configure the device for either "Cut-in High" (cooling) or "Cut-in Low" (heating) applications.
What is the maximum sensor lead length supported?
While it includes a 9-foot lead, the A99 sensor can be extended up to 300 feet using 18 AWG shielded cable, provided you calibrate for sensor resistance in the settings.
Is this model compatible with 24V systems?
No, the A421AET-01 is a line-voltage model. For low-voltage 24V applications, a different sub-model within the A421 Series must be selected.
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.
