Carrier HH19ZA190 Limit Switch

The Carrier HH19ZA190 Limit Switch is a critical safety component engineered for precise thermal monitoring in residential and commercial HVAC furnace systems. This temperature actuated switch is designed to protect equipment and ductwork from overheating by interrupting the electrical circuit when the high-limit threshold is reached. Specifically calibrated with a 190F-Open and 150F-Close thermal profile, it serves as a reliable flame rollout switch or primary high-limit sensor depending on the specific equipment configuration. Maintaining an accurate furnace high limit switch is essential for preventing heat exchanger damage and ensuring the blower fan cycles correctly during the heating sequence.

For contractors performing heat pump or gas furnace repair, the HH19ZA190 offers exact OEM specifications to maintain system integrity. As a dedicated Carrier replacement part, it is built with industrial-grade materials to withstand the high-cycle environments of modern air handlers and packaged units. Replacing a faulty thermal limit switch is a standard procedure when diagnosing a furnace that is "short cycling" or failing to initiate the combustion sequence. This switch is Non-Cancelable / Non-Returnable, so verify your model and serial number compatibility before installation.

• Precise Thermal Calibration: Factory set to open at 190°F and reset at 150°F for consistent safety monitoring.
• OEM Compatibility: Designed specifically for Carrier, Bryant, and Day & Night equipment to ensure seamless fitment.
• System Protection: Safely interrupts current to the gas valve or heating elements during over-temperature events.
• Standardized Mounting: Features a universal footprint for quick integration into existing limit control circuits.

What causes a Carrier limit switch to trip repeatedly?
Repeated tripping of the Carrier HH19ZA190 usually indicates restricted airflow caused by a dirty HVAC filter, blocked returns, or a failing blower motor, which allows heat to build up beyond the 190°F limit.

Is the HH19ZA190 an automatic or manual reset switch?
This model is an automatic reset limit switch, meaning it will re-close the circuit once the internal temperature drops back down to the 150°F closing setpoint.

Where can I find the HH19ZA190 in my furnace?
It is typically mounted on the furnace plenum or heat exchanger partition where it can directly monitor the temperature of the air passing through the HVAC system.

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.