Carrier HH680502 Limit Switch

The Carrier HH680502 Limit Switch is a critical safety component designed for precise thermal monitoring in residential and commercial furnaces. This 90-120F auto reset limit switch functions as a primary high-limit control, specifically engineered to open the electrical circuit if internal plenum temperatures exceed the 120°F threshold. Once the heat exchanger cools to the 90°F reset point, the switch automatically closes, restoring system operation. As a genuine OEM Carrier replacement part, it ensures exact fitment and calibration, maintaining the original engineering specifications of your HVAC equipment. This L120-30 limit switch (120°F trip, 30°F differential) is essential for preventing heat exchanger cracks and ensuring safe blower motor cycling. Technicians typically utilize this fixed-temperature furnace limit during HVAC emergency repairs or routine 100,000-cycle safety validations. Its compact footprint and standard spade terminals allow for a seamless drop-in installation, maintaining the air handler’s factory safety standards without the need for field modifications.

• Precise Thermal Calibration: Reliable 90-120°F range prevents nuisance tripping while protecting against catastrophic overheating.
• Automatic Reset Logic: Eliminates manual intervention after transient overheat events, reducing unnecessary service calls.
• OEM Compatibility: Designed specifically for Carrier, Bryant, and Payne air handlers to ensure consistent airflow sequencing.
• Heavy-Duty Construction: Built to withstand the high-cycle demands of modern high-efficiency gas furnaces.

What causes a Carrier limit switch to trip repeatedly?
Repeated tripping of the HH680502 is often caused by restricted airflow, such as a dirty 1-inch pleated filter, a failing blower motor, or blocked return air grilles. If the switch remains open after the system cools, the internal bimetal disc may have fatigued.

Can I bypass this switch for testing purposes?
Bypassing a safety limit is strictly for temporary diagnostic use by a qualified technician only. Operating a furnace without a functional Carrier furnace limit switch poses a significant risk of fire or heat exchanger damage.

Is the HH680502 a universal HVAC part?
While many switches look similar, this is a brand-specific HVAC component with a fixed 120°F cutout. Always verify the L-rating on the existing part to ensure the temperature differential matches the manufacturer’s data plate.

This item is not eligible for free shipping.

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.