Description
The Johnson Controls A19AAB-4 is a high-range mechanical temperature control engineered for dependable, precise temperature management across a wide range of HVAC and building automation applications. With a broad voltage compatibility of 24 to 277Vac and a robust SPST switching configuration, this control is a versatile solution for commercial and industrial environments.
Product Overview
The A19AAB-4 features an automatic reset function and an Open High switching action, meaning the switch opens as temperature rises above the setpoint — ideal for high-limit protection and cooling control applications. Its fixed 3.5°F differential ensures consistent, repeatable performance without the need for manual adjustment.
Key Features
- Voltage Range: 24 to 277Vac — broad compatibility with commercial HVAC systems
- Switch Type: SPST (Single-Pole, Single-Throw)
- Switching Action: Open High — switch opens on temperature rise
- Reset Type: Automatic Reset for continuous, hands-free operation
- Setpoint Range: 30°F to 110°F for high-range temperature control
- Fixed Differential: 3.5°F for consistent switching performance
- Capillary Length: 6 feet for flexible sensing element placement
- Sensing Bulb: 3/8″ diameter x 5″ length for accurate immersion or strap-on sensing
- Control Type: Mechanical — no power required for sensing operation
Application Highlights
The A19AAB-4 is well-suited for a variety of temperature control and high-limit applications including:
- Chilled water and cooling system control
- Air handling unit (AHU) temperature monitoring
- Commercial refrigeration and process cooling
- High-limit protection in hydronic and HVAC systems
- Fan and compressor staging based on sensed temperature
Technical Specifications
- SKU / Part Number: A19AAB-4
- Brand: Johnson Controls
- Voltage: 24 to 277Vac
- Switch Configuration: SPST
- Switching Action: Open High
- Reset: Automatic
- Setpoint Range: 30°F to 110°F
- Fixed Differential: 3.5°F
- Capillary Length: 6 feet
- Sensing Bulb Size: 3/8″ x 5″
- Control Type: Mechanical
Why Choose Johnson Controls A19AAB-4?
Johnson Controls is a globally recognized leader in building controls and HVAC solutions. The A19AAB-4 reflects their commitment to reliability and precision — delivering consistent temperature control performance with a rugged mechanical design that minimizes maintenance requirements and maximizes uptime in demanding commercial environments.
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