• Cooling Mode — When the Cooling mode is selected, the
indoor fan will operate continuously at the selected speed
if the speed is high, medium, or low. If the indoor fan is
in Auto. mode, the fan will change operating speeds de-
pending on the difference between the room temperature
and the set point. The reversing valve (QNH only) will be
energized. The compressor cannot run for 3 minutes from
the time the system starts up or for 3 minutes from the
time the compressor last operated. When the temperature
of the room is equal to or greater than the selected tem-
perature, the compressor and outdoor fan will operate un-
til the room temperature is 2° F below the set point, and
then shut off. When the room temperature is less than the
selected temperature, the compressor and outdoor fan re-
main off.
• Maximum Dehumidification Mode — When the Dehu-
midification mode is selected, the indoor fan will operate
continuously at the selected speed if the speed is high, me-
dium, or low. If the indoor fan is in Auto. mode, the fan
will change operating speeds depending on the room tem-
perature. If the room temperature is below the set point,
the indoor fan will run at ultra-low speed, and the com-
pressor could run for up to 4 minutes. (Ultra-low speed is
a control-driven speed [not user configurable] used to sample
the space when the fan would normally be off.) The re-
versing valve (QNH only) will be energized. The com-
pressor cannot run for 3 minutes from the time the system
starts up or for 3 minutes from the time the compressor
last operated.
Initial Operation — When the mode is first selected, one of
the following occurs:
1. If the room temperature is above or equal to the selected
temperature, the unit will operate for 16 minutes, and the
compressor and outdoor fan will operate. The indoor fan
will operate as in the Cooling mode. After 16 minutes of
operation (or when the room reaches 2° F below set point),
the unit switches to normal dehumidification operation.
2. If the room temperature is below the selected tempera-
ture, the unit will operate for 8 minutes as follows: the
compressor and outdoor fan will operate for 3 minutes.
The indoor fan will operate in low speed, and 30 seconds
after the compressor stops, the indoor fan stops. The unit
remains off for 1 minute, and then the indoor fan starts in
ultra-low speed for 30 seconds. The unit then switches to
normal dehumidification operation.
Normal Operation — One of the following will take place:
1. When the temperature of the room is equal to or greater
than the selected temperature (by not more than 3° F), the
unit will operate for 8 minutes as follows: the compres-
sor and outdoor fan will operate for 3 minutes. The in-
door fan will operate in low speed, and 30 seconds after
the compressor stops, the indoor fan stops. The unit re-
mains off for 1 minute, and then the indoor fan starts in
ultra-low speed for 30 seconds. The normal dehumidifi-
cation operation is repeated for the newly sensed room
temperature.
2. If the room temperature is equal to or greater than the
selected temperature, but not by more than between 4° F
and 6° F, the compressor and outdoor fan operate for
4 minutes. The indoor fan will run at ultra-low speed and
will stop 30 seconds after the compressor stops. After
3 minutes, the indoor fan runs at ultra-low speed for
30 seconds. The normal dehumidification operation is re-
peated for the newly sensed room temperature.
3. When the room temperature is equal to or greater than
4° F below the selected temperature, the system operates
as follows: The compressor and outdoor fan operate for
3 minutes. The indoor fan will operate at ultra-low speed
and will stop 30 seconds after the compressor stops. Af-
ter 4 or 5 minutes, the indoor fan starts in ultra-low speed
for 30 seconds. The normal dehumidification operation is
repeated for the newly sensed room temperature. If the
room temperature is still 4° F below the selected tem-
perature, the compressor, outdoor fan, and indoor fan re-
main off. After 7
1
⁄
2
minutes, the indoor fan operates at
ultra-low speed for 30 seconds. The normal dehumidifi-
cation operation is repeated for the newly sensed room
temperature.
• Heat Pump Heating Mode (Heat Pump Systems Only) —
When the Heat Pump mode is selected, the indoor fan will
operate at the selected speed if the speed is high, medium,
or low, unless overridden by the coil temperature (to pre-
vent cold drafts). If the indoor fan is in Auto. mode, the
fan will change operating speeds depending on the differ-
ence between the room temperature, the set point, and the
coil temperature. The reversing valve will be deenergized.
The compressor cannot run for 3 minutes from the time
the system starts up or for 3 minutes from the time it last
operated. When the temperature of the room is 8° F below
the selected temperature, the unit will operate in Heat Pump
mode until the temperature is 6° F above the selected tem-
perature, or the compressor runs for 40 minutes (which-
ever comes first). If the temperature of the room is less
than 7° F below or equal to the selected temperature, the
unit operates in Heat Pump mode until the selected set point
temperature plus 2° F is reached.
• Electric Heat in Heat Pump Heating Mode — Supplemen-
tal electric heat is enabled when the outside air thermistor
located in the outdoor unit is below 40 F and the room
temperature thermistor is equal to or less than 5.4 F below
set point. Electric heat will remain on until 1.8° F above
set point, then will turn off. Fan operation will be the same
as described previously in the heat pump heating mode.
NOTE: Electric heat control cannot be overridden.
• Demand Defrost Mode (Heat Pump Systems Only) — This
unit uses a demand defrost system to remove frost from
the outdoor coil during heating operation. The indoor and
outdoor fans are shut off during Defrost mode. See
Fig. 20. For high wall heat pump units, the electric heat is
OFF during Defrost mode.
• Sleep Mode — The Sleep mode timer turns the unit off
when the timer reaches zero minutes. The durations that
can be selected are 1, 2, 3 or 7 hours. After the initial
30 minutes, the user set point shifts approximately 1° F
warmer. This sequence repeats itself every 40 minutes up
to a total of 150 minutes. When Sleep mode is enabled,
the display on the remote controller is dimmed.
• On/Off Timer Mode — The on/off timer will turn the unit
on or off at a user selectable on and off time (this is one
time event only). The unit will start in the same mode and
at the same selected temperature as when the system shut
off. If the room temperature is not within approximately
5° F of the set point 40 minutes before start-up, the unit
runs before the user selected on time is reached to achieve
the set point temperature at start-up.
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