this specific part number is utilized in both furnace safety circuits and certain air conditioning high-limit applications

Precision Filtration: 20-micron internal filtration prevents debris from clogging capillary tubes or thermal expansion valves

Extended Service Life: Features a non-sticking Teflon-coated fabric-reinforced diaphragm and a stainless steel spring for consistent performance

This genuine OEM replacement part is specifically designed for Modine PD400 and BD400 unit heaters

Johnson Controls A99BB-400 Temperature Sensor this specific part number isThe Johnson Controls A99BB 400 Temperature Sensor is a precision PTC silicon sensor engineered for high accuracy temperature monitoring in commercial refrigeration and HVAC systems. Designed for seamless integration with System 450 controls and Penn A419 A421 series controllers, this thermistor style sensor features a linear resistance to temperature output, minimizing calibration drift in the field. The A99BB 400 is equipped with a 13 foot PVC cable