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Eubank 7AA1024A-1060A & 7AA2036A-2060A I&O Manual
07/2021 Rev.3
1.5 General Operation
Model
Ventilation Configuration
Temperature Range
Non-Economizer
Standard ("N")
20ºF – 120ºF (-7ºC – 48.9ºC)
Desert Duty ("ND")
32ºF – 130ºF (-0ºC – 54ºC)
Extreme Duty ("NE"), 60 Hz Only
0ºF – 130ºF (-18ºC – 54ºC)
With Economizer
Standard ("CE")
-40ºF – 120ºF (-40ºC – 48.9ºC)
Desert Duty ("CD")
-40ºF – 130ºF (-40ºC – 54ºC)
Extreme Duty ("CE"), 60 Hz Only
-40ºF – 130ºF (-40ºC – 54ºC)
Table 5. Ambient Temperature Operating Range
Refrigerant Cycle (Cooling Mode)
Eubank air conditioners use R-410A refrigerant in a conventional vapor-compression refrigeration cycle
to transfer heat from air in an enclosed space to the outside. A double blower assembly blows indoor
air across the evaporator. Cold liquid refrigerant passing through the evaporator is boiled into gas by
heat removed from the air. The warmed refrigerant gas enters the compressor where its temperature and
pressure are increased. The hot refrigerant gas condenses to liquid as heat is transferred to outdoor air
drawn across the condenser by the condenser fan. Liquid refrigerant is metered into the evaporator to
repeat the cycle.
Heating Mode
A wall-mounted thermostat controls the heating cycle of models which incorporate resistance heating ele-
ments. On a call for heat, the thermostat closes the heat relay to energize the indoor fan and the resistance
elements. Except on units with the optional dehumidification kit, the compressor is locked out during the
heating cycle. Please see Appendix A for instructions on field installing electric heaters.
Economizer Operation
The economizer is a regulated damper system with controls. The damper regulates the circulation of outside
air into the enclosure (when the outdoor air conditions are suitable) to reduce the need for mechanical
cooling, save energy, and extend compressor life.
Depending upon the options selected, the damper responds to the enthalpy of the outdoor air. On a call
for cooling from a space thermostat, it operates as follows:
When the enthalpy of the outdoor air is below the set point, the outdoor air damper is proportionally open
(and return air damper is proportionally closed) to maintain between 50°F and 56°F (10°C to 13°C) at
the mixed/discharge air sensor. Integral pressure relief allows the indoor air to exit the shelter through
the air conditioner.
When the enthalpy of the outdoor air is above the set point, the outdoor air damper closes to its minimum
position. A call for cooling from the space thermostat brings on mechanical cooling.
A built-in adjustable minimum position potentiometer controls the amount of outdoor air admitted to
meet minimum ventilation requirements.
1.6
Optional Controls & Packages
Hard Start Kit
Used on single phase equipment to give the compressor higher starting torque under low voltage conditions.
Generally not recommended on units with scroll compressors.
Extreme Duty Package
The Extreme Duty Package allows selected Eubank air conditioners to operate in extremely cold and hot
ambient conditions. The Extreme Duty Kit is always factory installed. Non-economizer air conditioners
will operate from 0° F to 131° F (-18° to 55°C). Economizer equipped air conditioners will operate from
-40° F to 131° F (-40° to 55°C).
