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(A/T)CONT900AC43UA Installer Guide
4 Heat/3 Cool/ Heat Pump
Communicating Programmable 3-Wire Hookup
dehumidification setpoint is 50%. In extremely high
humidity conditions, the Comfort Control keeps the
compressor running for up to 3°F (-1.7°C) below the
temperature setpoint. It does this while trying to
achieve the desired dehumidification setpoint and bal-
ancing that with the temperature setpoint. The maxi-
mum allowable dehumidification droop can be selected
in ISU 0383.
Droop
Droop is a feature that cycles the compressor on to
improve indoor comfort by removing moisture from the
air. The Droop cycle is activated when the indoor hu-
midity is above the user’s dehumidification setpoint.
When this function is active, the Comfort Control will
control temperature at 1°F or 2°F below the cooling
setpoint. The Droop cycle is deactivated when the
indoor humidity drops below the user’s dehumidifica-
tion setpoint. If the indoor humidity sensor fails, the
droop logic will always be enabled while in cooling
mode.
Comfort-R™ delay
When the indoor humidity is above the user’s dehu-
midification setpoint, Comfort-R™ delay will remove
humidity from the air by implementing a blower turn-
on delay of 15 or 30 seconds to “pre-chill” the coil.
Comfort-R™ delay applies to non-variable speed in-
door unit types only.
Dehumidification airflow
During any dehumidification control option, a lower
speed fan can be activated. The settings range from
80% to 100% in 5% increments (See Table 4, Installer
Setup number 0387, Page 14.) The default dehumidi-
fication airflow is 100%.
Proprietary humidity control
When enabled, this feature will disable any blower off
delays and disable continuous fan mode when
the indoor humidity is above the dehumidification
setpoint. This will help reduce coil condensation from
being evaporated back into the air stream.
• This feature, ISU 0388, is not shown unless
some form of dehumidification control is
selected.
• Proprietary humidity control does not af-
fect the fan operation when the fan setting at
the Comfort Control is in Auto or Circ modes.
Special heat pump features
Auxiliary heat lockout temperature
When an outdoor temperature sensor has been dis-
covered/enabled, none of the installed auxiliary heat
stages will turn on during heating operation above the
selected outdoor temperature. When the outdoor tem-
perature is less than the auxiliary heat lockout tem-
perature (ISU number 0360), the Comfort Control may
cycle the indoor heat on and off to satisfy the load.
During defrost, this outdoor temperature setting is ig-
nored and the defrost heater balance point outdoor
temperature thresholds are used.
For dual fuel applications, if the heat pump fails to
maintain heat while the outdoor temperature is above
the auxiliary lockout temperature, the furnace will be
used until the setpoint is reached, at which time heat
pump operation will resume.
Compressor heat lockout temperature
When an outdoor temperature sensor has been dis-
covered/enabled, only the installed auxiliary heat
stages will turn on during heat operation below the
selected outdoor temperature. When the outdoor tem-
perature is greater than the compressor heat lockout
temperature (ISU number 0350), the heat pump at-
tempts to satisfy the load. If the heat pump cannot
satisfy the load, the Comfort Control will transition to
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