Carrier HH19ZA175 Limit Switch

The Carrier HH19ZA175 Limit Switch is a critical safety component designed for precise thermal monitoring in residential and commercial HVAC equipment. Optimized for 125 VAC/VDC systems, this normally closed (NC) limit actuator operates with a specific 175°F open temperature and a 135°F close temperature. Built as a Pro-Dim high-temperature switch, it effectively prevents heat exchanger damage by breaking the 24V control circuit if internal temperatures exceed safe operating limits. This OEM limit switch features a compact 19mm pluggable design, facilitating quick integration into Carrier i-temp indoor units and furnace assemblies. Field performance is enhanced by the 40°F temperature differential, which prevents rapid short-cycling and allows the system sufficient cooling time before resetting. For technicians replacing HVAC temperature limit controls, the HH19ZA175 ensures reliable safety shutoff performance and high-accuracy thermal protection across a variety of Carrier furnace parts and air handling configurations.

Key Benefits:

• Precise Thermal Safety: Pre-set to open at 175°F and automatically close at 135°F to prevent equipment overheating.
• OEM Compatibility: Genuine Carrier replacement part specifically engineered for residential and light commercial heating systems.
• Durable Construction: Rated for temperatures ranging from -40°F up to the 175°F actuation point for long-term reliability in the plenum.
• Simplified Installation: Standard three-position switch with a 19mm pluggable footprint for efficient field replacement.

Common Questions:

• What causes a Carrier HH19ZA175 to trip? Typically, restricted airflow from a dirty filter, failed inducer motor, or blocked secondary heat exchanger causes the plenum temperature to reach the 175°F cutoff.
• Is this switch manual or automatic reset? The HH19ZA175 is an automatic reset limit switch, meaning it will re-close once the temperature drops to 135°F.
• Can I use this limit switch in other furnace brands? While this part is designed for Carrier specific equipment, compatibility depends on the required open/close setpoints and mounting dimensions.

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.