Johnson Controls A99BC-25 Temperature Sensor

The Johnson Controls A99BC-25 is a high-precision PTC silicon temperature sensor designed for demanding HVACR applications. Engineered with a passive PTC (Positive Temperature Coefficient) element, this sensor features a reference resistance of 1,035 ohms at 77?F (25?C), ensuring reliable performance when integrated with System 450, A421, and System 350 control modules. The A99BC-25 temperature sensor is equipped with a 9 3/4-inch high-temperature silicon cable, providing superior thermal stability across a broad operating range of -40 to 248?F (-40 to 120?C). This specific lead wire construction makes it the go-to choice for condenser fan cycling and defrost termination sensing in commercial refrigeration environments. Its splashproof stainless steel probe design ensures long-term accuracy and durability, even in high-humidity or condensing conditions. Use this OEM replacement part to maintain tight calibration in refrigeration temperature control loops and building automation systems.

Key Benefits

• Broad Operating Range: rated for environmental extremes between -40?F and 248?F (-40?C to 120?C).
• Chemical Resistance: The high-temperature silicon cable resists degradation better than standard PVC in industrial environments.
• Control Compatibility: Seamlessly interfaces with Johnson Controls/PENN A419, MR Defrost, and MS Multi-Stage modules.
• High Accuracy: Maintains a tight tolerance of +/- 0.9?F (0.5?C) within the critical range of 5?F to 167?F.
• Versatile Mounting: Compatible with A99-CLP-1 mounting clips and WEL11A-601R immersion wells for flexible installation.

Common Questions Is the A99BC-25 compatible with System 350 controls? Yes, the A99BC-25 is fully compatible with the legacy System 350 series as well as modern System 450 and A421 electronic temperature controls. What is the resistance value of the A99BC-25 at room temperature? The sensor lead resistance is 1035 ohms at 77?F (25?C). If your ohmmeter shows a significantly different reading at this temperature, the sensor may need replacement. Can this sensor be used for liquid immersion? The sensor itself is splashproof, but for direct liquid immersion, it should be used in conjunction with a stainless steel immersion well like the WEL11A series to protect the lead connections.

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.