Operation Mode And Control; Frozen Mode - Daikin LX10F11B3 Service Manual

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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 FULL COOL, or
COOLING OFF is
displayed on the upper
right of the screen. RETURN temperature (RS) is
displayed under SET POINT.
●Operation mode
FULL COOL＜Pull down＞
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℃ .
FULL COOL＜Modulation＞
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
Reheat coil (option)
LPT
HPT
HPS
Compressor
FULL COOL
▲
▼
EFM
Evaporator
HSV RSV
DMV
to Cooling OFF. Compressor stops and EFM
continues to run at low speed. If temperature rises
to ≧SP+0.5℃ , 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)
Falling
Temperature
SP
-0.5℃
Operation Flow in Frozen Mode
Valve chamber
EEV
EMV
ESV
PRV
CFM
Condenser
Receiver
Sight glass
1-11
Rising
Temperature
Full cool
with
Economized
cooling
+2.0℃
Modulation
+0.5℃
SP
Cooling OFF
Economizer
LSV
Dryer