Service manual

12-6
CONTROL SYSTEM
SM SX DCI 1-A.3 GB
12.3 Cool Mode
NLOAD is calculated according to the difference between actual room temperature and user set
point temperature by PI control.
In high/ medium/ low indoor fan user setting, unit will operate fan in selected speed.
In AutoFan user setting, fan speed will be adjusted automatically according to the calculated
NLOAD.
12.4 Heat Mode
NLOAD is calculated according to the difference between actual room temperature and user set
point temperature by PI control.
In high/ medium/ low indoor fan user setting, unit will operate fan in selected speed.
In AutoFan user setting, fan speed will be adjusted automatically according to the calculated
NLOAD.
12.4.1 Temperature Compensation
In wall mounted, ducted, and cassette models, 3 degrees are reduced from room temperature
reading (except when in I-Feel mode), to compensate for temperature difference between high and
low areas in the heated room, and for coil heat radiation on room thermistor.
The temperature compensation can be enabled/disabled by shortening of J2 on the indoor unit
Controller
Model J2 Shorted J2 Opened
Wall mounted Compensation Disabled Compensation Enabled
Cassette Compensation Enabled Compensation Disabled
Ducted Compensation Enabled Compensation Disabled
Floor/Ceiling Compensation Disabled Compensation Enabled
12.4.2 Indoor Fan Control in Heating Mode
Indoor fan speed depends on the indoor coil temperature:
12.5 Auto Cool/Heat Mode
When in auto cool heat mode unit will automatically select between cool and heat mode according
to the difference between actual room temperature and user set point temperature (.T). Unit will
switch from cool to heat when compressor is off for 3 minutes, and .T < -3.
Unit will switch from heat to cool when compressor is off for 5 minutes, and .T < -3.
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