Device Control System For Es Series - Hitachi RAS-5HVRNM1E Service Manual

5 Control System

5.1.2 Device control system for ES Series

Control subject
Control frequency of inverter
compressor
Opening degree expansion valve of
outdoor unit
Opening degree expansion valve of
indoor unit
Outdoor fan
4-Way valve (RVR)
Solenoid valve (SVA)
(Equalised pressure valve)
High/Low pressure balance
N O T E
• I.U.: Indoor unit
• O.U.: Outdoor unit
• Tc / Te: Condensing temperature / Evaporating temperature
• Td: Discharge temperature
• Tl: Liquid temperature
• Tg: Gas temperature
• Cap: Capacity
• Temp.: Temperature
120
SMGB0060 rev. 1- 12/2010
Cooling operation
The frequency control is determined
with the next parameters:
• Temperature difference
between air inlet temperature
and setting air temperature.
• Calculate the width of the
change by amount of change.
Fully open
• Control range of expansion
valve opening degree is
determined to optimize I.U. gas
pipe temp. (Tg) - I.U. liquid pipe
temp. (Tl) difference.
• Fan step is operated for O.U.
liquid pipe temp. (Te)
stabilization control
OFF
• Turn ON at starting
RAS-(4-10)H(V)RNS(1)E
• Control by indoor expansion
valve
RAS-(2-3) HVRN(1)(E)(S)
• Turn ON SVA before
compressor starting
RAS-(4-10)H(V)RNS(1)E
Purpose
Heating operation
The frequency control is
determined with the next
parameters:
• Temperature difference
between air inlet temperature
and setting air temperature.
• Calculate the width of the
change by amount of change.
• Control range of expansion
valve opening degree is
determined to optimize
temperature. on the top of
compressor.
• Specified opening degree at
normal control starting.
Afterward, controlled to
optimize I.U. liquid pipe temp.
(Tl).
• Fan step is controlled
according to O.U. liquid pipe
temp. and temp. on the top of
compressor.
ON
• Turn ON at starting
RAS-(4-10)H(V)RNS(1)E
• Control by outdoor expansion
valve
RAS-(2-3 HVRN(1)(E)(S)
• Turn ON SVA before
compresor starting
RAS-(4-10)H(V)RNS(1)E
Defrost operation
Fixed frequency (stop compressor
during 30 sec). After defrosting
condition was completed.
Fully open
Specified opening degrees
controlled by temp. on the top of
compressor. (Td).
Fan stop.
OFF
Turn ON at defrosting
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