Service manual

CONTROL SYSTEM
11.4 Indoor Unit Control
11.4.1 Indoor Fan Control
10 Indoor fan speeds are determined for each model. 5 speeds for each mode cool/dry/fan
or heat.
When user sets the indoor fan speed to a fixed speed (Low/ Medium/ High), unit will operate
constantly at set speed.
When Auto Fan is selected, indoor unit controller can operate in all speeds. The actual
speed is set according to the cool/heat load.
11.4.1.1 Turbo Speed
The Turbo speed is activated during the first 30 minutes of unit operation when auto fan
speed is selected and under the following conditions:
Difference between set point and actual room temperature is higher than 3 degrees.
Room temperature is higher than 22C for cooling or less th
an 25C for heating.
11.4.2 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.
11.4.3 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.
11.4.3.1 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 Enab
led Compensation Disabled
Ducted Compensation Enab
led Compensation Disabled
Floor/Ceiling Compensation Disabled Compensation Enabled
11-6
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