Carrier 39MN Series Custom Air Handling Unit (AHU-2)

Carrier 39MN Series (AERO) custom indoor air handling unit, factory marked AHU-2, model 39MN21W025BGL11XGE, serial 2218U35659, built in 2018. The unit is a horizontal, draw-section modular air handler with a galvanized/painted double-wall casing mounted on a structural base rail, arranged in the sequence shown on the unit nameplate: mixing box, flat filter section, hot water coil and plenum, and blow-thru supply fan section. Unit size 21 corresponds to a nominal airflow of roughly 10,500 CFM at 500 fpm face velocity. Per the unit nameplate, the supply fan section carries two 10 HP, 1800 RPM motors (Carrier fan 39MBK9HVB25584TCCK, motor 93MS0925BA300X0XSB) rated 460V/3-phase/60 Hz, 12.5 FLA / 15.6 MCA / 25 MOCP each, with a maximum continuous unit current of 31.0 A. The filter section takes six 20x25 pre-filters and six 20x25 main flat filters. The hot water coil and plenum (coil 28MHV232HDA065BRNC) is rated 300 PSIG maximum operating pressure at 200 F. Field piping at the unit is labeled chilled water supply and chilled water return with a condensate connection, indicating a chilled water cooling coil section as well. Controls and electrical devices visible on the unit include a factory-mounted ABB ACH-series HVAC variable frequency drive with keypad and local disconnect, an Eaton 60 A / 600 V heavy duty fused safety switch fed from panel 3PPH1 circuits 7, 9 and 11, a control/junction enclosure, and a Senva differential pressure sensor and transmitter mounted on the casing. In photo 3 the VFD display is lit and reporting 68.2% setpoint, 8.8 A and 1727 RPM, so the unit was energized and the fan running at the time of the visit. The unit is shown installed in a clean mechanical/production space, ducted on both the supply and return sides and hard-piped to the building chilled water and hot water systems. Overall listed dimensions are approximately 200 in. long x 96 in. wide x 90 in. high with an estimated shipping weight of 6,000 lbs. Disconnection of ductwork, piping and electrical service by trades will be required before removal.