Quest 746 Dehumidifier 480V | 730 Pints/Day, 3-Phase, R454B

How the Quest 746 Dehumidifier Performs

This overhead or floor unit is built for large flower rooms and greenhouses running on 480 V three-phase power. At 80 °F and 60% RH the unit pulls 730 pints of water a day at 8.3 pints/kWh. At 75 °F and 50% RH it still removes 480 pints a day at 6.1 pints/kWh. Current draw at the rated condition is only 4.9 A, for 3,665 W in total. The blower moves 1,650 CFM through an 18 x 20 x 2 in MERV 13 filter that traps dust, pollen and mould spores. R454B refrigerant carries a global warming potential 78 percent lower than older blends. DART technology slows the fan as defrost conditions approach, which helps keep the coil from icing in cool rooms. Onboard digital controls set RH in 1 percent steps, and a low-voltage terminal block accepts an external controller. Auto restart returns the unit to its last settings after a power cut. The cabinet measures 44.8 x 28.9 x 27.4 in, weighs about 300 lb and has integrated handles and hanging points. It is UL rated, ETL listed, assembled in Madison, Wisconsin, and backed by a 5-year limited warranty.

Sizing and Wiring a 3 Phase Dehumidifier

A 3 phase dehumidifier at this capacity suits rooms where transpiration from a full canopy outruns smaller units. Size the room's water load from irrigation volume minus runoff, then match it against the 75 °F figure for lights-off conditions. Have an electrician hardwire the unit, since it ships without a cord. Hang it from the built-in points on rated chain or strut, or set it level on a stand off the floor. Run the 3/4 in NPT drain to a floor drain or condensate pump with steady fall and no kinks. Keep the intake and discharge clear so air sweeps across the canopy instead of short-cycling. Duct kits allow the unit to sit in a plenum or mechanical space when the room has no spare ceiling. Check the filter every few weeks during heavy flower and replace it before it loads up. Keep the room between 56 and 95 °F, the unit's operating window. Set up this way, one machine can hold humidity steady through the wettest weeks of the cycle.

Key Features

• 730 pints/day: At 80 °F and 60% RH, with 8.3 pints/kWh efficiency.
• 4.9 A draw: Low current on a 480 V three-phase supply.
• 1,650 CFM airflow: Through a MERV 13 filter for cleaner room air.
• DART technology: Fan speed adjusts to slow coil icing.
• Overhead or floor: Integrated handles and hanging points.

Technical Specifications