Carrier HH18HA499 Limit Switch

The Carrier HH18HA499 Limit Switch is a critical high-temperature safety component engineered for Carrier, Bryant, and Payne gas furnaces. This automatic reset limit switch is designed to open the electrical circuit when internal plenum temperatures reach the 165°F threshold and closes once temperatures normalize to 125°F. It serves as a direct replacement for the HH18HA499A model, ensuring field compatibility and maintaining the original safety circuit integrity of the HVAC furnace inducer and heat exchanger assembly. Built for precision sensing, this L165-40 limit control prevents heat exchanger damage and hazardous operating conditions by monitoring for airflow restrictions or blower motor failure. For contractors managing HVAC repair projects, this OEM-spec component ensures exact fitment and reliable thermal response in high-efficiency residential furnaces.

• OEM Compatibility: Precision-matched for a wide range of Carrier-produced air handlers and gas furnaces, ensuring exact limit switch troubleshooting alignment.
• Automatic Reset Functionality: Transitions between 165°F (Open) and 125°F (Closed) states without manual intervention, maintaining system uptime.
• Interchangeable Design: Fully replaces HH18HA499A, simplifying inventory and part identification for service technicians.
• Durable Construction: Engineered to withstand high-cycling environments within the furnace plenum for long-term reliability.

What causes a Carrier HH18HA499 to trip frequently?
Repeated tripping is usually indicative of restricted airflow, often caused by a dirty furnace filter, blocked returns, or a failing blower motor assembly.

Is the HH18HA499 compatible with older Bryant models?
Yes, as an OEM Carrier furnace part, it is the standard replacement for various Bryant and Payne units that specify a 165-degree cutoff switch.

Can I bypass this switch for testing purposes?
Temporary bypassing for diagnostics should only be performed by a qualified technician; the switch must be operational during normal furnace cycles to ensure HVAC safety.

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.