Service manual

11-5
CONTROL SYSTEM
SM DUO38 1-E.1 GB
11.14 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.
11.14.1 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
11.14.2 Indoor Fan Control in Heat Mode
Indoor fan speed depends on the indoor coil temperature:
11.15 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 (ΔT).
Unit will switch from cool to heat when compressor is off for 3 minutes, and ΔT < -3.
Unit will switch from heat to cool when compressor is off for 5 minutes, and ΔT < -3.
ICTVL ICTH ICTL
ICTST
ICTT
CONTENT