Carrier HH18HA597 Limit Switch

The Carrier HH18HA597 Limit Switch is a critical safety component designed for high-temperature monitoring within HVAC furnace configurations. Rated for a 160-degree trip point, this SPST (Single Pole Single Throw) thermal switch acts as a primary safety cutout, ensuring the burner circuit opens if the heat exchanger exceeds safe operating parameters. This specific furnace limit control is engineered for a precise 160°F fixed temperature setting with a standard automatic reset function, meaning the circuit restores once the inducer or blower returns the plenum to a safe temperature range. The HH18HA597 serves as a direct replacement for HH18HA597B, featuring identical electrical ratings and mounting footprints to maintain OEM integrity. For contractors troubleshooting airflow restrictions or high-limit trips, replacing aged sensors with this Carrier Bryant Payne limit switch ensures system reliability and compliance with original safety specifications. Proper installation requires verifying 24V compatibility and securing the flange mounting for accurate thermal sensing.

Key Benefits for Technicians

• OEM Compatibility: Seamlessly replaces HH18HA597 and HH18HA597B without modification.
• Precise Thermal Calibration: Factory-set 160-degree limit prevents heat exchanger damage and unsafe operating conditions.
• Durable Construction: Built to withstand commercial and residential thermal cycling within Carrier-family furnaces.
• Safety Compliance: Restores factory-specified safety protocols for HVAC high limit protection.

Common Questions

How do I test if the Carrier HH18HA597 is faulty?
Using a multimeter set to continuity, check the terminals while the switch is cool. A functioning limit switch should show continuity (closed circuit) at room temperature and open the circuit when the 160-degree threshold is reached.

Can I use this switch in Bryant and Payne equipment?
Yes, this replacement limit switch is a standard component across the Carrier, Bryant, and Payne line, provided the part number matches the system’s original technical manual.

What causes this limit switch to trip frequently?
Repeated tripping of a furnace high limit switch is usually indicative of restricted airflow, such as a clogged filter, undersized ductwork, or a failing blower motor, rather than a sensor failure itself.

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.