Vilter 3-Fan Evaporator. SN: F 65591. Refrigerant: R-717 (Ammonia). Hot gas defrost. Tube material of construction: Galvanized steel. Number of fans: 3. Fan diameter: 2 ft. 6 in. Fin material of construction: Galvanized steel. Fins per inch: 3. For freezers or coolers, Vilter's High Performance (HP) medium capacity units are furnished with 1 HP or 1-1/2 HP motors and 30 diameter cast aluminum fans operating at 1150 RPM. Leeson fan motor - 1 hp, 1200 rpm, 230/460 V, 60 Hz, 3 phase. Inlets / outlets: (3) 1 ½ in. dia. port. (1) 3 in. dia. port. Overall dimensions: 13 ft. 3 in. L x 3 ft. 5 in. W x 3 ft. 1 in. H.