Bryant 542J, 548F, 549B manual Integrated Economi$Ers And Outdoor Air, Service Options

INTEGRATED ECONOMI$ERS AND OUTDOOR AIR

Optional EconoMi$ers and manual outdoor-air dampers intro- duce outdoor air which mixes with the conditioned air, improving indoor-air quality and often reducing energy consumption.

During a first stage call for cooling, if the outdoor-air tempera- ture is below the economizer control changeover set point, the discharge-air sensor modulates the economizer outdoor-air damper open to take advantage of free cooling provided by the outside air. When second-stage cooling is called for, the com- pressor is energized in addition to the economizer. If the outdoor-air temperature is above the changeover set point, the first stage of compression is activated and the economizer stays at vent position.

Accessory upgrade kits allow for either outdoor air enthaply changeover or for more precise differential enthalpy control.

Units can also utilize the factory or field-installed EconoMi$er. The EconoMi$er is microprocessor controlled and incorporates

aparallel, opposed-blade gear driven damper system. In addi- tion, it has a spring return built into the damper actuator to pro- vide reliable close-on-power-loss. The EconoMi$er comes equipped with up to 90% barometric relief capability for high outdoor airflow applications on 036-120 units only. Optional field-installed Barometric Relief package is available for use on 150,180 size units.

In addition, the EconoMi$er two-stage power exhaust acces- sory can be utilized to help maintain proper building pressure (036-120 units only). Single stage power exhaust is available for unit sizes 150,180 as a field-installed accessory.

For units without economizer, year-round ventilation is enhanced by a manual outdoor-air damper. On 036-120 units, a 25% or 50% manual damper is available as a field-installed accessory. Unit sizes 150,180 are equipped with a standard manual 25% damper.

SERVICE OPTIONS

Servicing a rooftop unit has never been easier with the new factory-installed service options for these rooftop units. These options include the following:

•Hinged access panels are provided for the filter/indoor-fan motor, compressors, indoor fan, and control box areas. Quick access to major components is accomplished by simply unlatching and swinging open the various panels. Each hinged panel is permanently mounted to the unit, thereby eliminating the concern of a dropped or wind-blown panel puncturing delicate roof materials. The 4 extended access panels are also equipped with ‘‘tie back’’ retaining devices to hold the door in the open position while servicing the unit.

•An external, covered, 115-v Ground Fault Interrupt (GFI) receptacle is provided as a convenient power source for drills, lights, refrigerant recovery units, or other electrical service tools. Simply connect the outlet to a field-supplied and prop- erly fused branch circuit power supply.

•An integral non-fused disconnect switch within the rooftop unit reduces installation time, labor and material costs. Safety is assured by an interlock which prevents access to the control box unless the switch is in the OFF position. In addition, the externally mounted handle incorporates power lockout capa- bility to further protect service personnel.

INDOOR-AIR QUALITY BEGINS WITH BRYANT ROOFTOPS

Sloped condensate pans minimize biological growth in rooftop units in accordance with ASHRAE (American Society of Heat- ing, Refrigeration, and Air Conditioning Engineers) Standard

62.Two-inch filters with optional dirty filter indicator switch pro- vide for greater particle reduction in the return air. The face-split evaporator coils improve the dehumidification capability of stan- dard units, maximize building humidity control.

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