Carrier HH18HA194 Limit Switch

For service technicians addressing limit circuit trips in Carrier, Bryant, or Payne furnaces, the Carrier HH18HA194 Limit Switch is the direct OEM replacement for safety circuit management. This critical furnace high limit switch is engineered with a temperature range of 140°F (open) to 180°F (close), featuring a reliable manual reset button that prevents the system from automatically cycling if a dangerous over-temperature condition occurs. Designed for HVAC troubleshooting on residential and industrial heating equipment, this snap disc safety switch ensures that the heat exchanger does not exceed thermal thresholds during airflow obstructions or blower failure.

The HH18HA194 is a 1-pole, temperature-actuated safety device that integrates seamlessly into Carrier furnace parts inventories. Often identified by alternative part numbers such as HH18HA194A or 7624A3591, this switch is vital for maintaining HVAC system diagnostics integrity. By cutting power to the gas valve or heating elements when internal plenum temperatures spike, it protects the primary heat exchanger from stress fractures and ensures operational safety for your clients. Whether you are performing an emergency furnace repair or a routine maintenance upgrade, installing a genuine Carrier HH18HA194 140-180F Auto Limit Switch provides the precision response required for modern high-efficiency systems.

• Precise Thermal Control: Calibrated specifically for a 140-180°F range to meet OEM safety standards for Carrier-branded equipment.
• Manual Reset Feature: Mandatory safety mechanism that requires a technician to inspect the system before restarting after a high-limit trip.
• Universal Compatibility: Direct replacement for various Bryant and Payne models, reducing the need for multiple truck-stock SKUs.
• Rugged Safety Design: Industrial-grade construction provides a durable HVAC replacement part capable of withstanding high-cycle environments.

Is the HH18HA194 an auto-reset or manual reset switch?
This model is a manual reset limit switch. If the temperature exceeds 180°F, the internal disc snaps open and must be manually depressed to close the circuit after the temperature drops and the underlying fault is corrected.

What causes this limit switch to trip frequently?
Repeated trips usually indicate restricted airflow. Check for a clogged furnace filter, collapsed ductwork, or a failing blower motor that is not moving enough CFMs across the heat exchanger.

Can I use this switch in non-Carrier brands?
While functionally similar to other 140-180F switches, this is specifically designed for Carrier, Bryant, and Payne units. Always verify the mounting bracket footprint and terminal orientation before installation in other brands.

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.