the hardware configurations differ between the 10-inch DR4200 and 12-inch DR4500 series

OEM Compatibility: Specifically engineered for Copeland compressors

including those from Furnas

Multi-Fuel Versatility: Certified for use with multiple fuel types

Carrier HH18HV135 Limit Switch 321702-401 the hardware configurations differ betweenThe Carrier HH18HV135 Limit Switch is a critical OEM replacement part designed for high limit thermal protection in residential and commercial HVAC systems. This disc style sensor features a normally closed (NC) configuration that triggers an open circuit at 135F to prevent heat exchanger damage or unsafe operating conditions. Once the temperature drops to 110F, the automatic reset capability restores the circuit, ensuring continuous system operation