11-6
CONTROL SYSTEM
SM YAZDCI 1-A.1 GB
11.3.3 Temperature
Measurements
11.3.3.1
Thermistor failures definition
Thermistor
Type a – Disconnected
Type b – Shorted
OAT
Temp < -30
o
C
Temp > 75
o
C
OCT
Temp < -35C
Temp > 75
o
C
CTT
Temp < -30
o
C
Temp > 125
o
C
HST
Temp < -30
o
C
Temp > 125
o
C
OMT
Temp < -35
o
C
Temp > 75
o
C
ICT
Temp < -30
o
C
Temp > 75
o
C
RGT
Temp < -30
o
C
Temp > 126
o
C
RLT
Temp < -30
o
C
Temp > 126
o
C
1.1.3.3.2 System responses for different thermistor failure
Thermistor Default value
System Reaction
OCT
43°C
OAT
6°C
CTT
43°C
Compressor is stopped.
OMT
43°C
Compressor is stopped in cooling mode.
HST
43°C
Compressor is stopped.
RGT 43°C
RLT
43°C
ICT
43°C
11.3.4
Flash Memory Programming
In order to upgrade the ODU software the auxiliary port will be used. A special application
should be run on a PC to transmit the new firmware. Special programmer (Panasonic)
should be used to update the S/W.
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 than 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.
