Daikin LX10F10A, Service Manual

Page: 16 / 126

1-11
1.4 Operation Mode and Control
1.4.1 Frozen Mode
●
Set Point and Control Temperature Sensor
Unit operates in frozen mode between Set Point
-10.0
℃ 〜 -30.0 ℃ . The temperature control in frozen
mode is controlled by the return air temperature
sensor (RS).
●
Display
FROZEN is displayed
on the upper left
and PULL-DOWN,
or COOLING OFF
is displayed on the
upper right of the screen. RETURN temperature
(RS) is displayed under SET POINT.
●＜
Pull-down operation
＞
Compressor runs at full capacity during pull-down
operation. ESV opens to activate economizer
circuit, then pull-down capacity is increased by sub-
cooling the liquid refrigerant entering EEV.
EFM runs at high speed but it runs low speed when
RS drops to -5.0
℃ .
＜
Modulated Cooling
＞
When RS drops to ≦ SP, unit will enter to the
modulating cooling. Compressor speed is modulated
in response to temperature difference between RS
and SP.
＜
Cooling OFF
＞
When RS still drops to ≦ SP-0.5 ℃ , unit will enter
to Cooling OFF. Compressor stops and EFM
continues to run at low speed. If temperature rises
to
≧ SP+1.0 ℃ , the unit will return to the modulated
cooling.
●
Condenser Fan Motor, CFM
CFM will run with high, low or OFF in response to
high pressure (HPT). (High Pressure Control)
Valve chamber
Economizer
Reheat coil (option)
Check valve
Condenser
Receiver
Compressor
HPT
HPS
EMV
ESV
LSV
Drier
EEV
LPT
Sight glass
Evaporator
CFM
EFM
RSV HSV
PRV
DMV
▲
▼
-0.5
℃
SP
SP
+1.0
℃
Falling
Temperature
Rising
Temperature
Cooling OFF
Operation Flow in Frozen Mode
+2.0
℃
Modulated
Cooling
Pull-down
with
Economized
cooling