Carrier HH18HA435 Limit Switch

Replace failing thermal components with the Carrier HH18HA435 Limit Switch, a critical safety device engineered for precise temperature monitoring in residential and commercial furnaces. As a veteran-grade 100-135F auto limit switch, this component is designed to interrupt the electrical circuit if the plenum temperature exceeds 135°F, preventing heat exchanger damage and ensuring system integrity. Once the temperature drops to the 100°F reset point, the switch automatically closes to resume standard heating cycles. This OEM Carrier HH18HA435 is the direct engineering replacement for legacy part number 1176115, featuring a compact footprint for streamlined installation in tight blower compartments. Its automatic reset functionality eliminates the need for manual intervention after minor temperature spikes, making it a reliable choice for high-duty cycle environments. Whether you are performing a routine service or an emergency HVAC limit switch replacement, this SPST thermal switch provides the exact calibration required to maintain factory specifications in Carrier, Bryant, and Payne air handlers.

• Direct OEM Compatibility: Provides a drop-in replacement for the Carrier 1176115 and various Bryant/Payne models without bracket modification.
• Calibrated Thermal Response: Fixed 135 degree open and 100 degree close thresholds ensure the furnace operates within safe thermal limits.
• Simplified Maintenance: The auto-reset limit control manages reset cycles autonomously, reducing callback volume for minor overheating events.
• Durable Construction: Built to withstand the constant thermal expansion and contraction typical of modern high-efficiency heat exchangers.

Is the HH18HA435 compatible with older 1176115 units?
Yes, the Carrier HH18HA435 is the official successor and direct replacement for the 1176115 switch, maintaining identical electrical ratings and thermal profiles.

What causes this limit switch to trip frequently?
Frequent tripping usually indicates restricted airflow due to a dirty filter, blocked registers, or a failing blower motor, causing the furnace limit switch to reach its 135°F cutout limit.

Can I use this as a manual rollout switch replacement?
No. This is an automatic reset limit switch. Safety protocols require manual reset switches for rollout applications to ensure a technician inspects the system for combustion issues before restart.

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.