Trane SWT1276 Limit Switch

As a seasoned tech, you know that keeping a furnace from over-firing starts with a reliable safety circuit. The Trane SWT1276 is a professional-grade 110-140F Auto Limit Switch designed to protect the secondary heat exchanger and surrounding components from thermal runaway. This OEM Trane replacement part features a fixed 140°F high-limit trip point and an automatic reset that closes the SPST normally closed (NC) circuit once the plenum temperature drops to 110°F. Built for high-cycle reliability in 120V HVAC controls, this auto reset furnace limit switch prevents short-cycling and erratic blower operation caused by restricted airflow or failing thermal sensors.

The Trane SWT1276 limit switch is engineered for a precise ±6°F tolerance on opening, ensuring the burner cuts out exactly when needed to maintain system integrity. With a 3-inch insertion depth and standard quick-connect terminals, it integrates seamlessly into existing wiring harnesses on compatible American Standard and Trane furnaces. For technicians troubleshooting a "limit open" fault code, this SWT1276 thermal switch offers the repeatability required to restore safe furnace operation without the nuisance tripping seen in lower-quality aftermarket alternatives.

• Precise Thermal Safety: Factory-calibrated to open at 140°F and auto-reset at 110°F for consistent furnace high-limit protection.
• OEM Compatibility: Exact drop-in replacement for Trane and American Standard SWT1276, SWT01276, and C340056P14 part numbers.
• Rugged Electrical Specs: Rated for 5.8 FLA / 34.8 LRA at 120V AC, providing durable service in residential and light commercial equipment.
• Service Lifecycle: Tested for up to 100,000 cycles to ensure long-term performance in demanding heating applications.

• What causes this limit switch to trip frequently? Most often, frequent tripping is a symptom of restricted airflow, such as a clogged filter, blocked return air, or a failing blower motor, rather than a faulty switch.
• Can I use a higher temperature limit if this one keeps opening? No. You should never bypass or increase the temperature rating of a limit switch; doing so risks cracked heat exchangers and fire hazards. Always replace with the specified 140°F rating.
• Does this switch require a manual reset? No, this is an auto-reset model. If the temperature is within the safe range (below 110°F), the contacts will automatically close to restore the 24V or 120V control circuit.

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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.