Trane SWT1258 Limit Switch

The Trane SWT1258 Limit Switch is a critical safety component designed for precise thermal regulation in Trane and American Standard furnaces. This automatic reset limit switch features a 3-inch insertion depth, ensuring accurate sensing within the heat exchanger airflow. It is engineered with a normally closed (NC) contact configuration, set to open at 170°F and reset at 140°F. As a genuine OEM replacement part, the SWT1258 provides a 1:1 fit for legacy and current systems, serving as the direct replacement for discontinued part numbers C340056P02 and SWT01258. Built for high-cycle reliability, this thermal limit switch prevents overheating conditions that can lead to cracked heat exchangers or unsafe operating parameters. For service technicians, utilizing the Trane furnace limit switch ensures the system stays within manufacturer specifications, maintaining proper blower cycling and burner safety without the risk of aftermarket incompatibility.

• Direct OEM Compatibility: Seamlessly replaces older part numbers C340056P02 and SWT01258 in Trane and American Standard units.
• Precise Thermal Control: Features a calibrated 170°F cut-out and a 140°F cut-in to protect high-value furnace components.
• Rugged 3-Inch Insert: The extended 3" probe depth allows for optimal temperature sampling in the supply air stream.
• Automatic Reset Functionality: Restores circuit continuity automatically once temperatures return to safe levels, reducing unnecessary downtime.

Is the SWT1258 compatible with my American Standard furnace?
Yes, as a genuine ServiceFirst/Trane component, it is widely utilized across both Trane and American Standard residential heating platforms. If your current switch is part number C340056P02, this is the official replacement.

What causes this limit switch to trip repeatedly?
While the SWT1258 is highly reliable, repetitive tripping (short-cycling) is often indicative of restricted airflow. Technicians should check for dirty filters, blocked returns, or a failing blower motor before assuming the switch is faulty.

Can I use a different length insert as a substitute?
Substitution is not recommended. The 3-inch insert is specifically sized to reach the manufacturer-defined "sweet spot" in the heat exchanger. Using a shorter or longer probe can result in inaccurate temperature readings and safety hazards.

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.