Trane / American Standard SWT01274 Genuine OEM Furnace Limit Switch (125°F / 3" Insert)

The Trane / American Standard SWT01274 is an original equipment manufacturer (OEM) safety component designed to prevent furnace overheating. This thermal limit switch is specifically calibrated to monitor the internal temperature of the plenum. It acts as a critical safety shut-off, designed to open the electrical circuit at 125°F, which safely shuts down the heating unit. Once the switch cools down to 95°F, it automatically closes the circuit, allowing the furnace to resume normal operation. This switch ensures the furnace remains within safe thermal parameters, protecting vital components like the heat exchanger.

Key Features

• Low-Temperature Safety Limit: Calibrated to "Open" at 125°F, providing immediate shutdown in specific commercial or packaged units that operate at lower airflow temperatures.
• Automatic Reset Function: The switch "Closes" the circuit at 95°F, ensuring the system can automatically recover after a temporary overheat condition is resolved.
• Robust Electrical Rating: Handles substantial electrical loads (5.8 FLA @ 120V AC), compatible with a wide range of residential and commercial units.
• Genuine OEM Reliability: This is an authentic Trane/American Standard part, built to precise factory standards, ensuring perfect fitment and safety compliance.

Product Details Specification

• Brand: Trane / American Standard
• Part Number: SWT01274
• Description: Thermal Limit Switch
• Open Temperature (Cut Out): 125°F
• Close Temperature (Cut In): 95°F (30°F Differential)
• Insert Length: Surface/Board Mount (Typically 3" overall size, not probe)
• Electrical Rating: 5.8 FLA / 34.8 LRA @ 120V AC
• Terminal Type: Quick Connect
• Number of Poles: 1
• Shipping Weight: 1.5 lbs

🛠️ HVAC Depot Pro Tip

A limit switch with a 125°F set point is usually a secondary or auxiliary limit in high-BTU downflow furnaces or specific packaged commercial units. It's often monitoring a different zone than the main limit. If this limit trips, ensure the ductwork configuration matches the manufacturer's specification (e.g., minimum duct length or required elbows). Low-temperature tripping often points to excessive airflow, which is rare, or more likely a misapplication of the limit switch location or a non-OEM replacement issue.

Cross-Reference

• Superseded Part:

  SWT01274, SWT1274, 389649, 349020

• Legacy / Manufacturing Numbers:

  C340056P12, X13540649120, 270159794707

• Rating ID:

  L125-30F (Indicating 125°F trip and 30°F differential).

Model Compatibility

• This limit switch is compatible with various Trane and American Standard high-efficiency furnaces and packaged units. Below are common compatible model prefixes; always verify the exact fit with your unit's data plate.

Trane Models:

• TDD: TDD120R9V5A1, TDD120R9V5B0, TDD140C960A0, TDD140C960C1, TDD2C100ACV52AB, TDD2D120A9V5VAA
• TUD: TUD1C080A9H41AA, TUD1C080A9H41BA

American Standard Models:

• ADD: ADD120R9V5A1, ADD120R9V5C4, ADD140C960A1, ADD140R960C0, ADD2C100ACV52AC, ADD2D120A9V5VAB
• AUD: AUD1C080A9H41BA, AUD1C080G9H41AA

Commercial Packaged Units:

• 4YCC/4YCY/4YCZ: 4YCC4042A1090AA, 4YCC4060E1115AA, 4YCY5036A1090AD, 4YCZ5036E1090AA, 4YCZ6036C1090AB