Stage (heating or cooling) operation. Provide low limit thermostat in supply air to close outside air dampers and stop supply fan and provide freeze protection. OPERATING CONTROLS - VARIABLE VOLUME UNITS Local temperature transmitter in supply air to signal electronic logic panel to control mixing dampers and cooling in sequence. Operate mixing section as first stage of cooling and revert to minimum outside air above approximately 75 degrees F as determined by temperature of return and outdoor air. Control cooling by cycling compressors, cylinder unloading, and hot gas bypass. Control logic to allow supply air reset under low load or airflow conditions. Provide 365 day time clock with spring carry over to control unit on schedule. At night, unit shall be off. Locate clock in remote control panel with status lights. Provide two-stage morning warm-up thermostat to hold outdoor dampers closed and energize heat until return air temperature reaches set point. Utilize VFDs to control duct static pressures. HEAT RECOVERY COIL Provide copper tube aluminum fin coil assembly with multiple circuits arranged to provide heat recovery. PACKAGED AIR CONDITIONING UNITS Packaged, self-contained, factory assembled, pre-wired unit, consisting of cabinet, compressor, condensing coil, evaporator fan, evaporator coil, discharge plenum, outside air connection, heating coil, air filters, and controls; fully charged with refrigerant and filled with oil. Assembly: Up or horizontal flow air delivery as indicated, in draw-through configuration. CABINET Frame and Panels: Galvanized steel with baked enamel finish, easily removed access-doors or panels. Insulation: Minimum 2 inch thick acoustic duct liner for lining cabinet interior.
Stage (heating or cooling) operation. Provide low limit thermostat in supply air to close outside air dampers and stop supply fan and provide freeze protection. OPERATING CONTROLS - VARIABLE VOLUME UNITS Local temperature transmitter in supply air to signal electronic logic panel to control mixing dampers and cooling in sequence. Operate mixing section as first stage of cooling and revert to minimum outside air above approximately 75 degrees F as determined by temperature of return and outdoor air. Control cooling by cycling compressors, cylinder unloading, and hot gas bypass. Control logic to allow supply air reset under low load or airflow conditions. Provide 365 day time clock with spring carry over to control unit on schedule. At night, unit shall be off. Locate clock in remote control panel with status lights. Provide two-stage morning warm-up thermostat to hold outdoor dampers closed and energize heat until return air temperature reaches set point. Utilize VFDs to control duct static pressures. HEAT RECOVERY COIL Provide copper tube aluminum fin coil assembly with multiple circuits arranged to provide heat recovery. PACKAGED AIR CONDITIONING UNITS Packaged, self-contained, factory assembled, pre-wired unit, consisting of cabinet, compressor, condensing coil, evaporator fan, evaporator coil, discharge plenum, outside air connection, heating coil, air filters, and controls; fully charged with refrigerant and filled with oil. Assembly: Up or horizontal flow air delivery as indicated, in draw-through configuration. CABINET Frame and Panels: Galvanized steel with baked enamel finish, easily removed access-doors or panels. Insulation: Minimum 2 inch thick acoustic duct liner for lining cabinet interior.
23_81_00_Decentralized_Unitary_HVAC_Equipment.docx