Secondary surface (fins) shall be of the plate-fin design using aluminum or copper, with die-formed collars. Fin design to be flat, waffle, or sine-wave in a staggered tube pattern to meet performance requirements. Collars will hold fin spacing at specified density, and cover the entire tube surface. Fins are to be free of oils and oxidation.

Coil casing material shall be galvanized steel at a 16 gauge minimum. Heavier material, stainless steel, copper or aluminum casings are available as required.

Intermediate supports are required every 50” of finned length and shall be bolted to top and bottom casing channels. Coil casings on top and bottom of coils are to have double-flange construction, allowing for vertical stacking of coils.

Seamless copper tubes shall be mechanically expanded into plate aluminum or copper fins to form an everlasting bond between primary and secondary surfaces. Tubes are to be mechanically expanded into fins (secondary surface) for maximum heat transfer.

Coils shall be tested at 550 psig using dry nitrogen, submerged under water. Dual-operator verification shall determine that all coils are leak-free.

Coils shall be certified to withstand 750 psig working pressures.

Connection is to be sweat type (SWT), MPT or FPT grooved or flanged as required.

Headers (manifolds), if required, shall be constructed of a minimum .060” wall seamless copper. Die-formed copper end caps are brazed on the inside of the headers, and rounded so as to prevent excessive pressure drop (Unless spun-closed — for sizes up to 1-3/8”). All coils shall be provided with 1/4” vents and drains.