Si30-408
Other Functional Operations
Basic Information
39
Functional Parts
No.
Part name
Symbol
(Electrical
symbol)
Function
Outdoor
unit sensor
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Outdoor thermistor
Ta
(R1T)
Used to detect outdoor temperature, thus
compensating discharge pipe temperature and others.
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Suction pipe thermistor
Ts
(R2T)
Used to detect suction pipe temperature, thus
conducting constant control of the suction
superheated degree in heating operation.
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Discharge pipe thermistor
(INV)
Tdi
(R31T)
Used to detect discharge pipe temperature, thus
conducting the protection control of compressor
temperature.
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Discharge pipe thermistor
(STD1)
Tds1
(R32T)
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Discharge pipe thermistor
(STD2)
Tds2
(R33T)
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Heat exchanger deicer
thermistor
Tb
(R4T)
Used to detect the liquid pipe temperature of air heat
exchanger, thus making judgment of defrosting
operation.
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Subcooling heat
exchanger gas pipe
thermistor
Tsh
(R5T)
Used to detect gas pipe temperature on the
evaporation side of subcooling heat exchanger, thus
conducting the constant control of outlet superheated
degree of the subcooling heat exchanger.
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Receiver outlet liquid pipe
thermistor
Tl
(R6T)
Used to detect outlet liquid pipe temperature of the
receiver, thus conducting the preventive control of drift
between outdoor units in heating operation on the
multi outdoor unit system.
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Oil equalizer pipe
thermistor
To
(R7T)
Used to detect oil equalizer pipe temperature, thus
detecting the opening / closing operation of the stop
valve for oil equalizer pipe.
N
High-pressure thermistor
Pc, Tc
(S1NPH)
Used to detect high pressure.
O
Low-pressure thermistor
Pe, Te
(S1NPL)
Used to detect low pressure.
Indoor unit
sensor
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Discharge air thermistor
Tr
(R1T)
Used for thermostat control and the compensation of
electronic expansion valve control.
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Liquid pipe thermistor
Tl
(R2T)
Used to control superheated degree (SH = Tg – TI) in
cooling operation.
• Used to freeze-up prevention control.
Used to control subcooled degree (SC = Tc – TI) in
heating operation.
• Used for hot start reset (34°C).
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Gas pipe thermistor
Tg
(R3T)
Used to control superheated degree (SH = Tg – TI) in
cooling operation.
Components
of outdoor unit
A
INV compressor
INV
(M1C)
Inverter compressors are driven by inverter at a
frequency in the range of 52 Hz to 210 Hz. STD
compressors are only operated with commercial
power supply. The following section shows the
number of operation steps in combined use of the
inverter and STD compressors.
RXY(Q)5M : 20 steps
RXY(Q)8, 10, 12M : 29 steps
RXY(Q)14, 16M : 35 steps
B
STD compressor 1
STD1
(M2C)
C
STD compressor 2
STD2
(M3C)
D
INV fan
—
(M1F)
This inverter fan operates at revolution speed in eight
steps by inverter drive for heat exchange with the air
heat exchanger.
E
Electronic expansion valve
(Main)
EV1
(Y1E)
Used for PI control in heating operation so that the
outlet superheated degree of the air heat exchanger
will be kept constant.
F
Electronic expansion valve
(Subcooling)
EV2
(Y2E)
Used for PI control so that the outlet superheated
degree of the subcooling heat exchanger will be kept
constant.
G
Solenoid valve (Hot gas)
SVP
(Y1S)
Used to prevent the transitional drop of low pressure.
H
Solenoid valve (Oil
equalizer)
SVO
(Y2S)
Used to conduct oil equalization between outdoor
units on the outdoor unit multi system.
I
Solenoid valve (Receiver
gas inlet)
SVL
(Y3S)
Used to maintain high pressure in cooling operation
with low outdoor temperature. Furthermore, used to
prevent the refrigerant from accumulating in outdoor
units in stop mode on the multi outdoor unit system.
J
Solenoid valve (Receiver
gas purging)
SVG
(Y4S)
Used to recover the refrigerant into the receiver.