Secondary surface (fins) shall be of the plate-fin design using aluminum, with die-formed collars. Fin design to be waffle type 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.
Seamless copper tubes shall be mechanically expanded into plate aluminum 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.
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 headered booster coils shall be provided with 1/4” vents and drains.
Connection is to be sweat type (SWT) or MPT.
Coil casing material shall be galvanized steel at a 18 gauge. Intermediate supports are required every 42” of finned length and shall be bolted to top and bottom casing channels.
Coils shall be tested at 550 psig using dry nitrogen, submerged under water. Dual-operator verification shall determine that all coils are leak-free.
Booster coils are guaranteed up to a maximum 300° F operating temp, and 250 psig maximum operating pressure.
All booster coils designed with 1/2” or 5/8” tubes are to have ARI Standard 410 certification and shall bear the ARI symbol. Coils outside the scope of ARI’s standard rating conditions or certification program will be acceptable to ARI since USA Coil is a current member of the ARI coil certification program, and coils will be rated in accordance with the ARI Standard 410.
Most HVAC steam heating coils operate with steam pressure below 25 PSIG, and a very large percentage are below 15 PSIG.......