Carrier HH18HA502 Limit Switch

The Carrier HH18HA502 Limit Switch is a critical OEM high-limit safety device designed for furnace temperature regulation in residential heating systems. Operating with a 140-180F temperature range, this component monitors the internal heat exchanger environment to prevent catastrophic failure and ensure safe operation. As an auto-reset hi-limit switch, it automatically restores the circuit once temperatures drop below the specified threshold, minimizing system downtime during transient overheating events. This Carrier replacement part is engineered to meet precise manufacturer specifications, ensuring seamless integration with models such as the 58CTA070-11108, 58CTA070-10108, and 58CTA070-12108. For technicians performing HVAC furnace repair, utilizing this genuine Carrier HH18HA502 ensures the safety circuit maintains its factory-calibrated trip points, protecting the heat exchanger and residential property from thermal damage.

Key Benefits for Contractors

• OEM Precision: Guaranteed Carrier HH18HA502 calibration ensures the furnace trips exactly at 180°F and resets at 140°F.
• System Protection: Acts as a primary furnace safety limit to prevent heat exchanger warping and roll-out conditions.
• Plug-and-Play Compatibility: Designed for specific Carrier, Bryant, and Day & Night furnaces, reducing installation time.
• High-Temperature Durability: Constructed with industrial-grade materials to withstand the rigorous cycling of high-efficiency gas furnaces.
• Auto-Reset Functionality: Eliminates the need for manual intervention after a temporary airflow restriction or minor overheat event.

Common Questions

What causes a Carrier HH18HA502 limit switch to trip?
Tripping is typically caused by restricted airflow, often due to a dirty air filter, a failing blower motor, or blocked return air ducts. This switch protects the system by breaking the heating circuit when temperatures reach the 180°F limit.

Is this an adjustable limit switch?
No. This is a factory-set 140-180F auto-reset switch. Attempting to adjust the temperature settings on a safety limit can cause hazardous operating conditions and system failure.

Can I use a universal limit switch instead of the HH18HA502?
While universal parts exist, HVAC technicians recommend this genuine Carrier OEM part because the mounting depth and thermal response time are calibrated specifically for the Carrier heat exchanger profile to ensure the highest safety standards.

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.