Special Control
SiUS281117
Function and Control
37
3. Special Control
3.1
Startup Control
On activation, following control is performed to lighten load of the compressor by back liquid and
the like. Also, the position of the four-way valve is defined.
Pc: High-pressure sensor detection value
Pe: Low-pressure sensor detection value
3.1.1 Startup Control in Cooling
3.1.2 Startup Control in Heating
Parts Name
Symbol
Electric Symbol
Operation
Remarks
RZR18/24/32P
RZQ18/24/30P
RZR36/42P
RZQ36/42P
Compressor
(INV.)
M1C
M1C
Differential
pressure control
Compressor operating frequency
increases by 2 step / 20 seconds until
Pc – Pe > 58 psi.
Outdoor unit
fan
M1F
M1F
M2F
High pressure
control
Initial fan speed is set to STEP 0.
1-step increase with Pc > 305 psi
1-step decrease with Pc < 261 psi
Four-way
valve
20S1
Y1S
Y1S
OFF
Electronic
expansion
valve (Main)
EV1
Y1E
Y1E
1400 pls
Solenoid valve
(Hot gas)
SVP
Y2S
Y2S
ON
Solenoid valve
(Receiver gas
discharging)
SVG
Y3S
OFF
Ending conditions
230 seconds
Pc – Pe > 58 psi
45 seconds
Parts Name
Symbol
Electric Symbol
Operation
Remarks
RZR18/24/32P
RZQ18/24/30P
RZR36/42P
RZQ36/42P
Compressor
(INV.)
M1C
M1C
Differential
pressure control
Compressor operating frequency
increases by 2 step / 20 seconds until
Pc – Pe > 58 psi
Outdoor unit
fan
M1F
M1F
M2F
STEP 8
Four-way
valve
20S1
Y1S
Y1S
ON
Electronic
expansion
valve (Main)
EV1
Y1E
Y1E
180 pls
Solenoid valve
(Hot gas)
SVP
Y2S
Y2S
ON
Solenoid valve
(Receiver gas
discharging)
SVG
Y3S
OFF
Ending conditions
145 seconds
Pc – Pe > 58 psi
15 seconds
OR
&
OR
&
