274569 - Miller 250F Normally Closed Thermal Switch M10x1.0

Reliable Thermal Protection for Miller Welders

The Miller 274569 Switch, Temp NC 250F Wire Lead 1/4 Fast-On M10X1.0 is a critical safety component designed to protect your valuable welding equipment from catastrophic overheating. As a genuine OEM part manufactured by Miller Electric, this temperature switch ensures that your machine operates within its safe thermal limits, preserving the longevity of internal components such as transformers, rectifiers, and circuit boards.

This specific switch operates as a Normally Closed (NC) device. In a standard safety circuit, the switch remains closed, allowing current to flow and the machine to operate normally. However, if the internal temperature of the monitored component reaches the calibrated threshold of 250°F (approximately 121°C), the switch opens. This interruption breaks the control circuit, effectively shutting down the welding output or triggering a thermal fault light, thereby preventing permanent damage to the power source.

Installation is designed to be precise and secure. The unit features an M10x1.0 metric thread, ensuring a tight fit into the designated heat sink or mounting block for accurate thermal transfer. The integrated wire leads are terminated with standard 1/4-inch Fast-On connectors, allowing for quick and reliable electrical connections without the need for soldering or complex wiring adjustments. When maintaining industrial welding equipment, using genuine Miller parts like the 274569 ensures that the safety parameters originally engineered into the machine are maintained.

Whether you are repairing a MIG, TIG, or Stick welder, verifying the functionality of your thermal switches is a key step in troubleshooting overheat errors. A faulty switch can either fail to protect the machine or cause nuisance tripping, halting production unnecessarily. Replacing a suspect unit with this authentic Miller component restores confidence in your equipment's reliability and safety systems.