Hitachi RAS-(4-12)HNP(1)(E) - Device Control System

5 Control System
136
SMGB0087 rev.0 - 12/2013
5.1 Devicecontrolsystem
Controlsubject
Purpose
Coolingoperation Heatingoperation Defrostoperation
Control frequency of
inverter compressor
The frequency control is determi-
ned with the next parameters:
• Ratio (IU capacity/OU capaci-
ty) for individual operation.
• Temperature difference bet-
ween air inlet temperature and
setting air temperature.
The frequency control is determi-
ned with the next parameters:
• Ratio (IU capacity/OU capaci-
ty) for individual operation.
• Temperature difference bet-
ween air inlet temperature and
setting air temperature.
Fixed frequency
(For RAS-(2-2.5)HVNP1 and
RAS-3HVNC1: 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 deter-
mined to optimize temperatu-
re. on the top of compressor.
• When number of IU is de-
creased, determined with IU
capacity. Ratio of (before/after
decrease or with above condi-
tion) for individual operation.
Fully open
Opening degree
expansion valve of indoor
unit
• Control range of expansion
valve opening degree is deter-
mined to optimize IU gas pipe
temperature (Tg) - IU liquid
pipe temperature (Tl) differen-
ce.
• The expansion valve opening
degree is controlled according
to the number of connected IU
for individual operation.
• Specied opening degree at
normal control starting. Af-
terward, controlled to optimize
IU liquid pipe temperature. (Tl)
• The expansion valve opening
degree is controlled according
to the number of connected IU
for individual operation.
Specied opening degrees con-
trolled by temperature on the top
of compressor. (Td).
Outdoor fan control
• Fan step is operated for OU li-
quid pipe temperature (Te) sta-
bilization control.
• Fan Step is controlled accor-
ding to OU 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.
Pd increase protection control.
RAS-(4-12)H(V)N(P/C)(1)(E)
• Turn ON at starting.
Pd increase protection control.
RAS-(4-12)H(V)N(P/C)(1)(E)
Turn ON at starting.
RAS-(4-12)H(V)N(P/C)(1)(E)
Solenoid valve (SVC)
(Hot gas discharge
bypass)
—
Turn ON depending on IU dis-
charge / suction temperature,
outdoor temperature, outdoor
liquid temperature, etc.
RAS-(3-12)H(V)N(P/C)(1)(E)
—
Solenoid Valve (SVF)
(Oil return)
Turn ON at compressor operation
RAS-12HN(P/C)
Turn ON at compressor operation
RAS-12HN(P/C)
Turn ON during defrosting
RAS-12HN(P/C)
High/Low pressure
balance
RAS-(2-2.5)HVNP1 /
RAS-3HVN(P/C)1(E):
Performed at the indoor expansion
valve.
RAS-(4-12)H(V)N(P/C)(1)(E):
Turn ON SVA during stop.
RAS-(2-2.5)HVNP1 /
RAS-3HVN(P/C)1(E):
Performed at the outdoor expan-
sion valve.
RAS-(4-12)H(V)N(P/C)(1)(E):
Turn ON SVA during stop.
—
 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