Designed to provide real-time refrigerant pressure sensing

While this specific model features a standard adjustable interface

While some Allied or Armstrong units share platforms

along with selectable valve-on and blower-off delays to optimize burner performance

replacing part 4ACE2556A without modification

Weil McLain 389-900-229 Sensor Freon Designed to provide real-time refrigerantThe Weil McLain 389 900 229 Sensor is a critical 10k ohm NTC component designed for multi functional integration within hydronic heating systems. Engineered for high accuracy thermal feedback, this Universal 3 In 1 Sensor serves as an outdoor reset sensor, an indoor strap on supply sensor, or a specialized well sensor depending on your installation requirements. When utilized as an outdoor sensor, it allows the boiler control to modulate water