Carrier HH18HV140 Limit Switch

The Carrier HH18HV140 is a high-precision SPDT Limit Switch designed for automatic temperature regulation in high-demand residential and commercial heating systems. Engineered for reliability as a critical safety component, this 110-140F Auto Limit Switch monitors the internal temperature of the heat exchanger, providing an essential shut-off mechanism to prevent overheating and potential equipment damage. With a 140°F cut-out and a 110°F cut-in temperature, the switch facilitates an automatic reset once the system cooled, ensuring seamless operation without manual intervention. This part is a direct OEM replacement and is technically identical to the HH18HV140-B, offering full compatibility with a wide range of Carrier, Bryant, and Payne furnace models. For technicians troubleshooting limit trip errors, this 140-degree limit switch provides the exact thermal response required to maintain factory safety specifications. This HVAC high limit sensor is built with rugged internal contacts to withstand frequent thermal cycling in harsh environments, making it a standard inventory item for professional HVACR maintenance and repair.

• Critical Safety Protection: Automatically interrupts the heating circuit at 140°F to protect the heat exchanger from cracked surfaces and thermal stress.
• Direct OEM Compatibility: Verified as identical to HH18HV140-B, ensuring a perfect physical and electrical fit for Carrier-family equipment.
• Automatic Reset Function: Features a 30°F differential that allows the system to re-engage once temperatures drop to 110°F.
• Precision Thermal Sensing: High-quality limit switch 110-140F calibration ensures accurate temperature detection and reduces nuisance tripping.
• Durable SPDT Construction: Designed for longevity under rigorous industrial and residential HVAC cycles.

Is the HH18HV140 the same as the HH18HV140-B?
Yes, the HH18HV140 is identical in design and technical specifications to the HH18HV140-B and can be used interchangeably in all supported HVAC applications.

What causes this limit switch to trip frequently?
Frequent tripping is often a symptom of restricted airflow. Technicians should check for dirty air filters, blocked return registers, or a failing blower motor before concluding the limit switch itself is defective.

Does this switch require a manual reset?
No, this is an auto limit switch. It will automatically close the circuit and allow the furnace to run again once the temperature reaches the 110°F cut-in point.

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.