5 Control System
118
SMGB0064 rev.0 - 08/2011
5.1 Device control system
5.1.1 Device control system for IVX 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:
• Ratio (I.U. capacity/O.U. ca-
pacity).
• Temperature difference be-
tween air inlet temperature and
setting air temperature.
The frequency control is deter-
mined with the next parameters:
• Ratio (I.U. capacity/O.U.
capacity)
• Temperature difference be-
tween air inlet temperature
and setting air temperature.
Fixed frequency (stop compres-
sor during 30 sec. After defrosting
condition was completed)
Opening degree expansion valve
of outdoor unit
Fully open
• Control range of expan-
sion valve opening degree
is determined to optimize
temperature. on the top of
compressor.
• When number of I.U. is de-
creased, determined with I.U.
capacity. Ratio of (before/
after decrease or with above
condition).
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.
• The expansion valve opening
degree is controlled according
to the number of connected I.U.
• Specied opening degree at
normal control starting. After-
ward, controlled to optimize
I.U. liquid pipe temp. (Tl)
• The expansion valve opening
degree is controlled according
to the number of connected I.U.
Specied 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 increased number
of I.U.: step-up decreased
number of I.U.: step-down
• Fan Step is controlled ac-
cording to O.U. liquid pipe
temp. and temp. on the top of
compressor.
• Increased number of I.U.:
step-up decreased number
of I.U.: step-down (limited the
lowest by outdoor temp.)
Fan stop.
4-Way valve (RVR) OFF ON OFF
Solenoid valve (SVA) (Equalised
pressure valve)
• Turn ON at starting
• Turn ON for 1 min. at low pres-
sure switch activation.
RAS-(3-12)H(V)RNM(2)(E)
• Turn ON at starting
• Turn ON for 1 min. at low
pressure switch activation
• Turn ON at pressure control
switch activation.
Turn ON a defrosting
Solenoid valve (SVB) (Liquid
return)
Turn ON at starting
RAS-(3-12)H(V)RNM(2)(E)
Turn ON at starting Turn ON at starting
Solenoid Valve (SVF) (Oil return)
Turn ON at compressor operation
RAS-(3-12)H(V)RNM(2)(E)
Turn ON at compressor operation Turn ON at staring
High/Low pressure balance
Turn ON SVA or SVB before com-
pressor starting
RAS-(8-12)HRNM
— —
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
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