External Equalization: Compensates for pressure drops across the evaporator to maintain stable superheat

For other models like the 800 or 801

the Teflon non-stick material is chemically compatible with standard HFCs and HCFCs

Built to handle the high-temp environment of the furnace inducer assembly

Engineered for precision refrigerant flow control

Aprilaire 51 Relay 321894-709 External Equalization: Compensates for pressureThe Aprilaire 51 Relay is a high performance current sensing relay engineered for precision in 120V HVAC applications. Designed to monitor electrical load and trigger auxiliary equipment, this HVAC current switch ensures seamless synchronization between your furnace blower and accessories like whole house humidifiers or electronic air cleaners. This Aprilaire 51 sensing relay features a compact, durable design that simplifies the installation process