The Johnson Controls A99BC-500C Temperature Sensor is a high-precision PTC silicon sensor engineered for demanding HVACR refrigeration applications. This passive Positive Temperature Coefficient sensor features a reference resistance of 1,035 ohms at 77?F (25?C), ensuring reliable input for PENN System 450, A419, and A421 electronic temperature controls. Designed with a 16 3/8-foot (5-meter) high-temperature silicon cable, the A99BC-500C maintains integrity across a broad operating range of -40?F to 248?F. The stainless steel sensing probe provides superior moisture resistance and durability in splashproof environments like walk-in coolers, display cases, and freezers. Its calibrated thermistor element allows for seamless field replacement without the need for control recalibration, making it an essential component for condenser fan cycling and defrost termination logic. With 22 AWG leads and 0.9?F accuracy between 5?F and 167?F, this sensor delivers consistent performance in high-humidity, condensing conditions. Key Benefits: Broad Compatibility: Fully compatible with Johnson Controls System 450, System 350, and A419 digital controllers. High-Temperature Resilience: The silicon cable jacket is rated for the full sensor range up to 248?F, preventing insulation breakdown. Simplified Calibration: Factory-calibrated PTC sensing element ensures plug-and-play accuracy across different control modules. Chemical Resistance: The stainless steel bulb prevents corrosion in aggressive environments; however, avoid exposure to silicon-based fluids. Common Questions: Can I extend the lead wire? Yes, leads can be extended up to 800 feet (244 m) using 22 AWG wire with negligible effect on resistance-to-temperature accuracy. Is this sensor waterproof? The probe design is splashproof and rated for 0-100% RH condensing environments, making it ideal for refrigeration coils. What happens if the resistance deviates? If the measured ohms do not match the standard A99B resistance chart at a known temperature, the sensor should be replaced to ensure proper system cycling. 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.
