5 Control system
Device control system
SMGB0091 rev.2 - 11/2015
78
5.1 Device control system
Control subject
Purpose
Cooling operation
Heating operation
Defrost operation
Control frequency of
inverter compressor
The frequency control is determined with
the next parameters:
•
Ratio (IU capacity/RASC capacity) for
individual operation.
•
Temperature difference between indoor
unit air inlet temperature and room
setting temperature.
The frequency control is determined with
the next parameters:
•
Ratio (IU capacity/RASC capacity) for
individual operation.
•
Temperature difference between indoor
unit air inlet temperature and room
setting temperature.
Fixed frequency
(stop compressor
during 30 sec. After
defrosting condition
was completed).
Opening degree
expansion valve of
RASC
Fully open
•
Control range of expansion valve
opening degree is determined to
optimise temperature on the top of
compressor.
•
When number of IU has decreased,
the expansion valve opening degree
is determined with IU capacity ratio of
before/after decrease or with control
range for individual operation.
Fully open
Opening degree
expansion valve of
indoor unit
•
Control range of expansion valve
opening degree is determined to
optimise IU gas pipe temperature
(Tg) - I.U. liquid pipe temperature (Tl)
difference.
•
The expansion valve opening degree is
controlled according to the number of
connected IU for individual operation.
•
Specified opening degree at normal
control starting. Afterward, controlled
to optimise IU liquid pipe temperature
(Tl).
•
The expansion valve opening degree is
controlled according to the number of
connected IU for individual operation.
Specified opening
degrees controlled
by temperature
on the top of
compressor. (Td).
RASC fan
•
Fan step is operated for RASC liquid
pipe temperature (Te) stabilization
control.
-
Increased number of I.U.: Step-up.
-
Decreased number of I.U.: Step-
down.
•
Fan step is controlled according to
RASC liquid pipe temperature and
temperature on the top of compressor.
-
Increased number of I.U.: Step-up.
-
Decreased number of I.U.:
Step-down (limited the lowest by
outdoor temperature)
Fan stop.
4-Way valve (RVR)
OFF
ON
OFF
Solenoid valve (SVA)
(Equalised pressure
valve)
•
Turn ON at starting.
Pd increase protection control.
•
Turn ON at starting.
Pd increase protection control.
Turn ON at starting
Solenoid valve (SVC)
(Hot gas discharge
bypass)
—
Turn ON depending on I.U. discharge /
suction temperature, outdoor temperature,
outdoor liquid temperature, etc.
—
High/Low pressure
balance
Turn ON SVA during stop.
Turn ON SVA during stop.
—
I.U.:
Indoor unit
Tc / Te:
Condensing temperature / Evaporating temperature
Td:
Discharge temperature
Tl:
Liquid temperature
Tg:
Gas temperature
Pd:
Discharge pressure
Cap:
Capacity
Temp.:
Temperature