Special Control
SiUS281117
Function and Control
43
3.7
Pressure Equalization Prior to Startup
Ta: Outdoor air temperature
Pc: High-pressure sensor detection value
Pe: Low-pressure sensor detection value
Before activating the compressor, the activation load is lightened by equalization across the
compressor. In addition, inverters turn ON electricity and capacitors are charged.
Parts Name
Symbol
Electric Symbol
Operation
Remarks
RZR18/24/32P
RZQ18/24/30P
RZR36/42P
RZQ36/42P
Compressor
(INV.)
M1C
M1C
OFF
Outdoor unit
fan
M1F
M1F
M2F
Cooling: OFF
Heating: Ta > 78.8°F; STEP 8,
Ta
78.8°F; OFF
Four-way
valve
20S1
Y1S
Y1S
Keep former condition.
Electronic
expansion
valve (Main)
EV1
Y1E
Y1E
0 pls
Solenoid valve
(Hot gas)
SVP
Y2S
Y2S
ON
Solenoid valve
(Receiver gas
discharging)
SVG
Y3S
OFF
Ending conditions
3 minutes
Pc – Pe < 29 psi
OR
