Johnson Controls A99BA-200 Sensor

The Johnson Controls A99BA-200 is a high-precision PTC Silicon Sensor designed for demanding commercial refrigeration and HVAC monitoring. Built as a passive Positive Temperature Coefficient sensing element, this unit delivers a standard reference resistance of 1,035 ohms at 77°F (25°C). Engineered for accuracy within 0.9°F across the critical range of 5°F to 167°F, it ensures reliable data for defrost termination sensing, condenser fan cycling, and space temperature control in walk-in coolers or freezers. This specific model features a 6 1/2-foot (2m) shielded cable, providing superior protection against electromagnetic interference (EMI) in industrial environments. The stainless steel probe construction offers splashproof durability, making it ideal for high-humidity applications. Compatible with Johnson Controls/PENN System 450, A419, and MR/MS series controllers, the A99BA-200C is a staple for contractors requiring long-term stability and field-proven thermal response in complex digital control architectures.

• Shielded Signal Integrity: Equipped with a 6.5-foot shielded PVC cable to minimize electrical noise and ensure clean signal transmission to the controller.
• Wide Operating Envelope: Supports a broad temperature sensing range from -40°F to 212°F (-40°C to 100°C) for versatile refrigeration and heating use.
• Industrial Durability: Features a 2-inch stainless steel bulb that provides excellent corrosion resistance and rapid thermal conductivity.
• Extended Range Capability: Sensor leads can be extended up to 800 feet using 14 AWG wire without significant resistance errors.

• Is the A99BA-200 submersible? No, while the sensor probe is splashproof and designed for high-humidity environments, it should not be directly immersed in liquids without a WEL11A-601R immersion well.
• Which controllers are compatible with this PTC sensor? This sensor is specifically designed for the PENN System 450, A419, and other 1k ohm PTC-compatible digital electronic controllers.
• How do I troubleshoot a suspected sensor failure? Disconnect the leads and measure the resistance with an ohmmeter. At 77°F (25°C), you should see approximately 1,035 ohms; significant deviations indicate the need for a replacement.

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.