Indeeco Electric Duct Heater. Type: TFZU. 6.3 KW. DWG No. L931N1: C19159-A-0. Control Panel. Catalog No. 103-A3-480-20I. S/N: 1E04 79523. Panel power supply: 480 V, 20 amps, 3 phase. (6) Tubular finned coils. No. of steps: 1. Coil dimensions: 1 in. dia. x 1 ft. 4 in. L. Heater power supply: 8 hp, 480 V, 60 Hz, 3 phase. This is a flanged unit. Inlets/outlets: 1 ft. 4 in. L x 1 ft. W. (duct). Indeeco duct heaters utilize the finest of construction principle and techniques. The coil is constructed of a .475 in diameter stainless steel sheath and contains a 80% nickel, 20% chromium resistance wire insulated from the sheath by a magnesium oxide powder, compacted to rock-like density. The elements are flanged, making them individually removable. All heaters are suitable for installation in ducts with up to one inch of interior lining. Overall dimensions: 2 ft. 3 in. L x 1 ft. 4 in. W x 3 ft. H.