IV.  Special Control   
1. Startup Control 
Table 20 - Startup Control in Cooling Operation 
Component  Operation  Remarks 
Compressor  Capacity control  Compressor operational frequency increases by 1 step / 1 sec 
Outdoor unit fan (FAN A)  High pressure control 
Initial step for 90 seconds 
1-step increase with Pc > 392 psi 
1-step decrease with Pc < 305 psi 
Outdoor unit fan (FAN B)    High pressure control 
Initial step for 90 seconds 
1-step increase with Pc > 392 psi 
1-step decrease with Pc < 305 psi 
Electronic expansion valve (EXV A)  350P   
Electronic expansion valve (EXV B)  350P   
Electronic expansion valve (EXV C)  PI control   
Solenoid valve (SV4)  1000 seconds ON  After, Normal control 
Solenoid valve (SV7)  Normal control   
Ending conditions  1000 seconds   
Table 21 - Startup Control in Heating Operation 
Component  Operation  Remarks 
Compressor  Capacity control  Compressor operating frequency increases by 1 step / 1 second 
Outdoor unit fan (FAN A)  T4 and capacity control   
Outdoor unit fan (FAN B)  T4 and capacity control   
Four way valve (ST1)  ON   
Electronic expansion valve (EXV A)  Heating EXV control   
Electronic expansion valve (EXV B)  Heating EXV control   
Electronic expansion valve (EXV C)  0P   
Solenoid valve (SV4) 
200 seconds OFF,800 seconds ON 
  After, Normal control 
Solenoid valve (SV7)  Normal control   
2. Oil Return Operation 
Table 22 - Oil Return Operation in Cooling mode 
Outdoor Unit Component  Pre Oil Return Operation  Oil Return Operation  Post Oil Return Operation 
Electronic expansion valve (EXV A) 
Electronic expansion valve (EXV B) 
Electronic expansion valve (EXV C) 
Solenoid valve (SV7)  Normal control  Normal control  Normal control 
Ending conditions  75 seconds 
120 seconds 
 
 
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