The Ranco A22-391 Constant Differential Control is a specialized temperature control switch engineered for high-demand commercial refrigeration and freezer applications. This SPDT (Single Pole Double Throw) control is designed without an "off" position, ensuring continuous monitoring and regulation for HVACR refrigeration temperature control. With a constant differential of 8.0°F, it maintains tight thermal tolerances across its operating range. The integrated 66-inch capillary tube sensing element provides the necessary reach for complex evaporator coil or air temperature sensing configurations. Technical specifications include a normal On temperature of 32.0°F and Off at 27.0°F, while the cold setting operates at 19.0°F On and 11.0°F Off. The warm setting targets 51.0°F On. This robust HVAC mechanical control is a direct replacement for various Ranco A22 series parts, providing reliable cycle management for reach-ins, walk-in coolers, and display cases requiring precision commercial freezer thermostat functionality. Key Benefits for Contractors: Constant Differential Performance: Maintains a fixed 8.0°F variance, preventing short-cycling and protecting compressor longevity in commercial environments. Versatile SPDT Switching: Allows for flexible wiring configurations, managing either a cooling circuit or an alarm/auxiliary signal. Extended Sensing Capability: The 66-inch capillary length provides ample room for routing through thick insulation or large cabinets. Dependable No-Off Design: Specifically built for systems that must maintain active regulation without the risk of manual accidental shut-off. Common Questions & Technical Support: What is the primary application for the Ranco A22-391? This control is optimized for commercial refrigerators and freezers where a constant temperature differential is required to stabilize the cooling cycle. Can I use this control to replace a standard Ranco A12 series? The A22-391 features an SPDT switch and a constant differential. You must verify that the original wiring and thermal requirements match these specific SPDT parameters before installation. Does this unit have a manual override? No, this specific model does not have an "off" position, ensuring the system remains under thermostatic control at all times. 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.
