Hitachi RAS-(4-12)HRNM(2)(E) - Device Control System for es Series

5 Control System
120
SMGB0064 rev.0 - 08/2011
5.1.2 Device control system for ES Series
Control subject
Purpose
Cooling operation Heating operation Defrost operation
Control frequency of inverter com-
pressor
The frequency control is deter-
mined with the next parameters:
• Temperature difference be-
tween air inlet temperature and
setting air temperature.
• Calculate the width of the
change by amount of change.
The frequency control is deter-
mined with the next parameters:
• Temperature difference be-
tween 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 de-
termined to optimize tempera-
ture. on the top of compressor.
Fully open
Opening degree expansion valve
of indoor unit
• Control range of expansion
valve opening degree is deter-
mined to optimize I.U. gas pipe
temp. (Tg) - I.U. liquid pipe
temp. (Tl) difference.
• Specied opening degree at
normal control starting. After-
ward, controlled to optimize
I.U. liquid pipe temp. (Tl).
Specied opening degrees control-
led by temp. on the top of com-
pressor. (Td).
Outdoor fan
• Fan step is operated for O.U.
liquid pipe temp. (Te) stabiliza-
tion control
• Fan step is controlled accord-
ing to O.U. liquid pipe temp.
and temp. on the top of com-
pressor.
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(2)E
• Turn ON at starting
RAS-(4-10)H(V)RNS(2)E
Turn ON at defrosting
High/Low pressure balance
• Control by indoor expansion
valve
RAS-(2-3) HVRN(S)2
• Turn ON SVA before compres-
sor starting
RAS-(4-10)H(V)RNS(2)E
• Control by outdoor expansion
valve
RAS-(2-3) HVRN(S)2
• Turn ON SVA before compre-
sor starting
RAS-(4-10)H(V)RNS(2)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