Carrier 50FK - Manual (Page 10)

Economizer — Economizer control is used to control
the outside and return air dampers of the unit, to satisfy space
cooling demand using all outside air (when permitted), and
to satisfy cooling in conjunction with compressor operation
(when conditions permit). During Occupied periods without
cooling demand, the outside-air dampers will be at the user-
configured Minimum Damper Position (at P5 on accessory
board). During Unoccupied periods, the outside-air dampers
will be closed.
The economizer is available as a factory-installed option.
The user can install an accessory differential enthalpy sensor
to enhance economizer control. Refer to the installation sec-
tion for field wiring of the sensor.
ENTHALPY CONTROL — Outside air enthalpy control is
standard with the factory-installed economizer option. En-
thalpy is sensed by a controller located behind the end out-
side air hood. The control can be accessed by removing the
upper hood filter. See Fig. 17.
DIFFERENTIAL ENTHALPY — Added efficiencies in econo-
mizer control can be gained by installing a differential en-
thalpy sensor in the return air duct. When differential enthalpy
control is installed, the economizer control will use the air
stream with lower enthalpy (outside air or return air) to pro-
vide for lower compressor operating costs during integrated
economizer cycle operation. The differential enthalpy sen-
sor is installed in the return-air duct.
STANDARD
FILTERS
BAG
FILTERS
Fig. 11 — Thermistor T2 Location, Size 034-048 Units
STANDARD FILTERS BAG FILTERS
(054-074 Only)
Fig. 12 — Thermistor T2 Location, Size 054-104 Units
Fig. 13 — Thermistor T3 and T4 Locations,
Size 034-048 Units
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