Demand Defrost Control detects ice build-up on outdoor coil. Replaces Rheem model 47-102684-83. Nominal Timing Specifications-Defrost Lockout Time 34 min, Max Defrost Time 15 min, Max Frosting Time 6 Hrs., Short Cycle Lockout Time 5 min. No Hi/Lo Pressure Switch Inputs, Outdoor Fan Relay: PSC 1-speed, Mounting: Metal Standoffs, Dimensions: 3.375" x 3.625". 48" Ambient & Defrost Temperature Sensors included.