Johnson Controls A99BB-200 Temperature Sensor

The Johnson Controls A99BB-200 is a high-precision PTC silicon temperature sensor specifically engineered for reliable monitoring in professional HVACR applications. As a veteran-grade refrigeration temperature sensor, it features a 6-1/2 foot PVC cable and a stainless steel sensing bulb to withstand moisture-heavy environments like walk-in coolers and display cases. This model serves as the designated A99CB-200 replacement; however, please note that the A99BB-200 utilizes a non-shielded cable compared to the shielded original. If your installation is subject to high electrical noise or requires critical industrial isolation, consider verifying your grounding requirements or opting for the A99BA series.

Operating within a broad HVAC temperature range of -40?F to 212?F (-40?C to 100?C), the A99BB-200 integrates seamlessly with PENN System 450 controls, A419 electronic temperature controls, and MR/MS series defrost modules. The calibrated PTC thermistor ensures linear resistance performance, allowing for field lead extensions up to 800 feet with negligible signal degradation. Whether you are managing condenser fan cycling or defrost termination, this sensor provides the 1,035-ohm reference resistance (at 77?F) necessary for accurate system cycles and equipment protection.

Key Benefits for Technicians

• Broad Compatibility: Native support for Johnson Controls A421, System 350, and DX-9100 series controllers.
• Reduced Troubleshooting: Pre-calibrated PTC element allows for "plug-and-play" replacement without the need for manual recalibration.
• Environmental Resilience: The splashproof design and stainless steel bulb prevent corrosion in condensing and high-humidity environments.
• Lead Extension Flexibility: Supports 22 AWG wire extensions for remote sensing in large-scale commercial refrigeration layouts.

Common Questions

Can the A99BB-200 replace the shielded A99CB-200?
Yes, the A99BB-200 is the direct functional replacement. While the sensing element remains identical, the cable is non-shielded. Ensure the wiring is routed away from high-voltage lines to prevent electromagnetic interference.

What is the resistance reading at room temperature?
At 77?F (25?C), this sensor should read approximately 1,035 ohms. If your resistance deviates significantly from the standard A99 series resistance-to-temperature chart, the sensor may require replacement.

Is this sensor suitable for immersion applications?
For pipe sensing or liquid immersion, always use this sensor in conjunction with a WEL11A-601R immersion well and thermal conductive paste to ensure accurate heat transfer and sensor protection.

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.