Weil McLain 383-500-602 Temp Sensor

The Weil McLain 383-500-602 is a critical return/supply temperature sensor kit engineered for precise thermal monitoring within Weil McLain Ultra and SlimFit series boilers. This 12 Kohm NTC thermistor assembly provides real-time data to the control board, allowing for accurate modulation and preventing short-cycling. As a dedicated boiler replacement part, it ensures the system maintains the delta-T required for high-efficiency condensing operation. These sensors are designed for direct integration with the heat exchanger, measuring the fluid temperature as it enters and exits the block. For a service technician, replacing a fouled or drifting 383-500-602 sensor is standard procedure when troubleshooting E02 or E04 fault codes on Ultra Gas or Ultra Commercial units. This kit typically includes two sensors with white connectors, facilitating a simplified swap for both the supply and return lines to restore hydronic heating system accuracy and peak performance.

• Optimized System Efficiency: Precise 12 Kohm resistance ensures accurate temperature feedback for condensing boiler modulation.
• Broad Compatibility: Fits a wide range of models including Weil McLain Ultra Series 2, 3, and 4, and SlimFit Series 550-750.
• Direct OEM Replacement: Replaces factory-installed supply and return sensors to clear sensor-related error codes.
• Durable Construction: Built to withstand the high-temperature environment of residential and commercial heat exchangers.

Is this a single sensor or a dual kit?
The 383-500-602 is a kit that includes two (2) sensors, typically used for simultaneous replacement of the supply and return temperature monitoring points.

What are the symptoms of a failing Weil McLain temp sensor?
Common indicators include inconsistent water temperatures, the boiler failing to fire despite demand, or specific diagnostic codes on the U-Control display relating to sensor shorts or open circuits.

Do I need to drain the boiler to replace these sensors?
Yes, because these sensors typically monitor the liquid temperature within the flow and return pipes or the heat exchanger manifold, the system should be isolated and partially drained to prevent leaks during the swap.

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.