22
MODES OF OPERATION
The units have 5 main operating modes:
1. Fan Only
2. Cooling
3. Heating (heat pumps only)
4. Auto
5. Dehumidification (Dry)
The units have 2 other modes (manual operation) that are operated
in unique situations:
1. Auto Forced Mode (Emergency)
2. Test Mode
Fan Mode Only
In this mode, the system circulates the room air without changing
the room air temperature.
Cooling Mode
In this mode, the system cools and dries the room air with the fan
running continuously, either at a selected fan speed or Auto fan
speed. The fan runs even when the compressor cycles off. This
feature enhances room comfort and efficiency of the system.
When the unit is operating in cooling, two sub modes can also be
selected:
1. Sleep Mode is an energy saving feature that changes the set
point automatically.
2. Turbo Mode is a comfort feature on the 9k and 12k units
where the set point is reached quickly by having the fan run
on high speed regardless of the speed that has been selected.
Compressor and Outdoor Fan Operation
The compressor and outdoor fan motor cycle on and off based on
the conditions of the set point and the room temperature as shown
below. There is no minimum run time.
T = Room Temperature
Ts = Set Point Temperature
Compressor off
fan off
Compressor and
outdoor fan on
Room temp. down
0 1.8°FT-Ts
Room temp. up
A08106
Fig. 24 – Compressor and Outdoor Fan -- Cooling Mode
Indoor Fan Operation
When in cooling mode, the fan runs continuously either at the
chosen set speed , or in Auto mode, where the speed is determined
by the microprocessor based on the difference between the room
temperature and the temperature set point as shown below:
Room temp. up
Room temp. down
T= Room Temperature
Ts = Set Point Temperature
9.0 °F7.2 °F1.8 °F T-Ts
Low fan
High fan
Med fan
A08107
Fig. 25 – Auto Fan -- Cooling Mode
Sleep Mode
When in cooling mode, additional energy savings can be realized
by selecting the Sleep setting. When the Sleep setting is selected,
the temperature set point is adjusted automatically as shown below:
Set point
Time (hour)12
1.8
°
F
1.8
°
F
A08108
Fig. 26 – Sleep Mode
The unit will shut off 7 hours after the Sleep Mode is selected.
Turbo Mode
When in cooling mode, selecting Turbo will allow the indoor unit
to satisfy the temperature set point as quickly as possible. In Turbo
Mode, the indoor fan will shift to high speed and either run
continuously for 20 minutes or until the user pushes the Turbo
button again, at which point the fan speed will return to the original
setting.
Heating Mode
In this mode, the system heats the room air with the indoor fan
running at either the selected speed or on Auto. As in the cooling
mode, the indoor fan will run continuously unless interrupted by
the cold blow algorithm. This algorithm will not allow the fan to
run if the indoor coil temperature drops below a preset value.
The sleep function can be selected while the unit is running in the
Heating Mode. Defrost is controlled by the on--board
microprocessor.
Compressor and Fan Operation
The compressor and outdoor fan cycle on and off based on the
actual room temperature versus the set point as shown below.
When the compressor starts, it will run continuously for 7 minutes
even if the set point condition is satisfied.
The 4--way value is energized in heating and will stay energized for
2 minutes after the mode is changed into a non--heating mode.
Compressor on
outdoor fan off
Room temp. up
Room temp. down
Compressor off
outdoor fan on
Ts+5.4*Ts+3.6*Ts T
T = Room Temperature
TS = Set Point Temperature
* For 9k & 12k Units Only. For 18k and 24k units, numbers will be 5.4 and 7.2 respectively.
A08109
Fig. 27 – Compressor and Outdoor Fan -- Heating Mode
38/40MVC, MVQ