Service manual

12-8
CONTROL SYSTEM
SM CINCO 1-A.1 GB
12.3.5.2 The following thermistor faults are detected by the system:
Thermistor Thermistor is Disconnected Thermistor is Shorted
OCT Temp < -35 °C Temp > 75 °C
OAT Temp < -30 °C Temp > 75 °C
CTT Temp < -30 °C Temp > 130 °C
HST Temp < -30 °C Temp > 125 °C
OMT Temp < -30 °C Temp > 75 °C
RGT Temp < -30 °C Temp > 75 °C
RLT Temp < -30 °C Temp > 75 °C
ICT Temp < -30 °C Temp > 75 °C
RAT Temp < -30 °C Temp > 75 °C
12.3.5.3 System operation whenever a thermistor fault occurs
 Sensor IDU status ODU Mode Type Status Report* Blink** System Operation
1 OAT NA Any A Fault Yes Yes
Normal, replace reading with default
value.
2 OAT NA Any B Fault Yes Yes
3 OCT NA Any A Fault Yes Yes
Normal, replace reading with default
value.
4 OCT NA Any B Fault Yes Yes
5 CTT NA Any Any Fault Yes Yes Compressor is stopped.
6 HST NA Any A Fault Yes Yes
Compressor is stopped.
7 HST NA Any B Fault Yes Yes
8 OMT NA Cool Any Fault Yes Yes Compressor is stopped.
9 OMT NA Heat/Idle Any Fault Yes Yes
Use the OCT instead. If OCT faulty
also – stop compressor.
10 RGT
i
/RLT
i
Inactive
(Available)
Cool/Heat/
Idle
Any Fault Yes Yes
Normal, replace reading with default
value.
11 RGT
i
/RLT
i
Inactive
(Unavailable)
Cool/Heat/
Idle
Any No No No
Normal, replace reading with default
value.
12 RGT
i
Active Heat Any Fault Yes Yes
Normal, replace reading with default
value.
13 RLT
i
Active Cool Any Fault Yes Yes
Normal, replace reading with default
value.
*- Report outdoor unit fault to the indoor unit.
**- Indicate fault code with outdoor unit LED’s.
12.4 Indoor Unit Control
12.4.1 Load calculation
LOAD 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 LOAD.
12.4.2 Indoor Fan Control
12.4.2.1 Indoor fan control - FAN Mode
 When T/H/M/L speed is set by user, IFAN will work in constant requested speed.
 When Auto-Fan is set by user, IFAN speed will be set according to the following graph:
VLOW
Turbo
HIGH
MEDIUM
LOW
DT3210-1 4