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Orange County West Campus Office Building -HVAC <br />PDC Project 23020 In-Row Computer Room Air Conditioners 23 81 24.01 - 3 <br />heat transfer,reduce air side pressure drop,increase energy efficiency,and shall significantly <br />reduce the system refrigerant volume required.EC fans and fan operating techniques shall <br />provide reduced maximum sound levels.Various methods shall be available to match indoor <br />unit type,maximum outdoor design ambient,and maximum sound requirements <br />B.Aluminum Microchannel Coil <br />1.Microchannel coils shall be constructed of aluminum microchannel tubes,fins,and manifolds. <br />Tubes shall be flat and contain multiple,parallel flow microchannels and span between <br />aluminum headers.Full-depth,louvered aluminum fins shall fill spaces between the tubes. <br />Tubes,fins,and aluminum headers shall be oven-brazed to form a complete refrigerant-to-air <br />heat exchanger coil.Copper stub pipes shall be electric resistance welded to aluminum coils <br />and joints protected with polyolefin to seal joints from corrosive environmental elements.Coil <br />assemblies shall be factory leak tested at a minimum of 300 psig (2068 kPag).Hot gas and <br />liquid lines shall be copper and shall be brazed using nitrogen gas flow to the stub pipes with <br />spun-closed ends for customer piping connections.Complete coil/piping assembly shall be <br />then filled and sealed with an inert gas holding charge for shipment. <br />C.Fan Motor/Blade Assembly <br />1.The fan motor/blade assembly shall have an external rotor motor,fan blades and fan/finger <br />guard.Fan blades shall be constructed of cast aluminum or glass-reinforced polymeric <br />material.Fan guards shall be heavy gauge,close-meshed steel wire,coated with a black, <br />corrosion-resistant finish.Fan terminal blocks shall be located in an IP54 enclosure located <br />on the top of the fan motor.Fan assemblies shall be factory[if <br />!supportFootnotes][1][endif]balanced,tested before shipment and mounted securely to the <br />condenser structure. <br />D.EC Fan Motor <br />1.The EC fan motors shall be electronically commutated for variable speed operation and shall <br />have ball bearings.The EC fans shall provide internal overload protection through built-in <br />electronics.Each EC fan motor shall have a built-in controller and communication module, <br />linked via RS-485 communication wire to each fan and the Premium Control Board,allowing <br />each fan to receive and respond to precise fan speed inputs from the Premium Control Board <br />E.Electrical Controls <br />1.Electrical controls and service connection terminals shall be provided and factory-wired inside <br />the attached control panel section.A locking disconnect switch shall be factory-mounted and <br />wired to the electrical panel and controlled via an externally mounted locking and lockable <br />door handle.Only high[if !supportFootnotes][1][endif]voltage supply wiring and low-voltage <br />indoor unit communication/interlock wiring shall be required at condenser installation. <br />F.Locking Disconnect <br />1.A locking-type disconnect switch shall be factory-mounted and wired to the electrical panel. <br />The switch shall be accessible from the outside of the unit with the door closed and shall <br />prevent access to the high[if !supportFootnotes][1][endif]voltage electrical components until <br />switched to the Off position.The locking disconnect shall be lockable in support of <br />lockout/tag-out safety programs. <br />G.Cabinet <br />1.The condenser cabinet shall be constructed of bright aluminum sheet and divided into <br />individual fan sections by full width baffles.Internal structural support members,including the <br />coil support frame,shall be galvanized steel for strength and corrosion resistance.Panel <br />doors shall be provided on two sides of each coil/fan section to permit coil cleaning.An <br />electrical panel shall be contained inside a factory mounted,NEMA 3R weatherproof <br />electrical enclosure.Units with the 575V option shall include a second factory mounted, <br />NEMA 3R weatherproof electrical enclosure opposite the main electrical enclosure. <br />2.Legs shall be provided to mount the unit for vertical air discharge with rigging holes for <br />hoisting the unit into position.Standard height shall be 18 in.(457 mm). <br />2.10 CONDENSATE PUMP <br />A.Provide a dual-float condensate pump.The pump shall be complete with integral primary and <br />secondary float switches,pump,motor assembly and reservoir.The secondary float shall send a <br />Docusign Envelope ID: 8DED1454-68D2-4E36-9FC6-E56FF2124E5D