Hitachi RAS-3HVRNS - Device Control System for es Series

5.1.2 Device control system for ES Series
Control subject
Purpose
Cooling operation Heating operation Defrost operation
Control frequency of inverter
compressor
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.
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.
Fixed frequency (stop compressor
during 30 sec). After defrosting
condition was completed.
Opening degree expansion valve of
outdoor unit
Fully open
• Control range of expansion
valve opening degree is
determined to optimize
temperature. on the top of
compressor.
Fully open
Opening degree expansion valve of
indoor unit
• Control range of expansion
valve opening degree is
determined to optimize I.U. gas
pipe temp. (Tg) - I.U. liquid pipe
temp. (Tl) difference.
• Specified opening degree at
normal control starting.
Afterward, controlled to
optimize I.U. liquid pipe temp.
(Tl).
Specified opening degrees
controlled by temp. on the top of
compressor. (Td).
Outdoor fan
• Fan step is operated for O.U.
liquid pipe temp. (Te)
stabilization control
• Fan step is controlled
according to O.U. liquid pipe
temp. and temp. on the top of
compressor.
Fan stop.
4-Way valve (RVR) OFF ON OFF
Solenoid valve (SVA)
(Equalised pressure valve)
• Turn ON at starting
RAS-(4-10)H(V)RNS(1)E
• Turn ON at starting
RAS-(4-10)H(V)RNS(1)E
Turn ON at defrosting
High/Low pressure balance
• 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
• 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
—
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
5 Control System
120
SMGB0060 rev. 1- 12/2010