50DW Weathermaker II Rooftop Units Constant Volume Cooling
20 to 27 Nominal Tons
Model 50DW is a COOLING ONLY unit built for horizontal supply and return. The standard unit is factory assembled, rated in accordance with ARI standard 360, tested in accordance with UL standard 1995, and listed by ETL and CSA.
Features/Benefits
Design flexibility: Dedicated horizontal unit is ideal for replacement or special applications such as thru-the-wall jobs or jobs where sound must be attenuated before the duct penetrates the roof. Ducts connect directly to unit, using factory-supplied flanges. Horizontal units may be curb mounted or slab mounted.
Unit efficiency: Dual serviceable, semi-hermetic compressors on intertwined evaporator coil ensures excellent full and part-load efficiency with EERs (Energy Efficiency Ratio) to 9.7. Dual refrigerant circuits provide standby capability should one circuit require service.
Reliable 06D Carlyle compressors are proven performers. Constant volume units have 2 stages of capacity with field-installed accessory unloaders available to provide 5-stage operation. Optional hot gas bypass valve permits low-load operation of the refrigeration system. Optional integrated economizer permits free cooling and utilizes a solid-state enthalpy control. The economizer operates in conjunction with mechanical cooling when required and is factory installed for either vertical or horizontal operation. A field-installed differential enthalpy sensor is available as an accessory for even greater energy savings. The use of differential enthalpy allows the unit control to compare the enthalpy difference between return air and outside air to determine which is more economical to condition for enhanced energy savings. Field-installed rainhood/filter assembly prevents moisture or objects from entering the unit.
Installation/serviceability: Small footprint requires less roof area and makes unit easier to rig. Low unit profile allows units to be mounted closer to edge of building while remaining out of public view. Up to 60% smaller volume than comparable units. Single-point electric connections are standard on all units, regardless of voltage or optional heater size. Electrical service access can be made through roof curb or side of unit. Hinged access panels are located so as to make it easy to reach standard serviceable components for maintenance. No fasteners need to be removed, which reduces servicing time and prevents roof leaks caused by discarded screws puncturing the roof.
Unit controls Constant volume units utilize a solid-state relay board that interfaces with any 2-stage heat/2-stage cool thermostat. Economizer units utilize a mixed air thermistor with a field-adjustable set point. Unit design is ETL (Electrical Testing Laboratory) and CSA (Canadian Standards Association) certified. On constant volume (CV) units, a set of terminals is provided for a switch or relay to disable the unit; all other connections must be made directly to the appropriate device.