Description of Functions and Operation
SiENBE28-901
54
Air Cooled Refrigeration Condensing Unit
(5) Electrical expansion valve control
(5)-1. Outdoor electrical expansion valve (Y1E(EV1)) ······ This only applies to the Japanese
domestic models. The valve will be activated when the reverse cycle defrost is used.
For the LRM(L)EQ** models, a "0pls" command will be used all times.
(5)-2. Outdoor electrical expansion valve (Y2E(EV2)) ······ This valve will provide refrigerant gas
injection flow rate control, overheating protection, and condensation protection.
Initial valve opening: 43pls (mode 1), 55pls (modes other than mode 1)
Control flow
(5)-3. Outdoor electronic expansion valve (Y3E(EV3)) ······ An electronic expansion valve is
installed in the intermediate injection line of the INV compressor. The valve will operate in
synch with the INV compressor, and allow the refrigeration oil to be returned to the INV
compressor(s) that are in operation. It also creates an economizer circuit by means of gas
injection. In addition, the valve will control the difference in discharge pipe temperatures
between INV and STD compressors.
(6) Solenoid valve control
For 8, 10, 12, 15, and 20 AY1 models, a solenoid valve is installed in the intermediate injection
line of the STD compressor. The valve will operate in synch with STD compressor, and allow
the refrigeration oil to be returned to the STD compressor(s) that are in operation. Additionally,
the valve will create a gas injection economizer circuit.
Outdoor EV2 condensation
avoidance control
or
• The discharge pipe temperature
thermistor value < 60°C
• Intermediate superheat (SH) <8 to
12K continuously for 20 seconds
or more.
Outdoor EV2
normal control
Every 10 seconds
Every 20 seconds
Outdoor EV2 overheat
protection control
or
&
• INV compressor continues to
operate for 60 seconds or more
• STD compressor continues to
operate for 90 seconds or more.
• Min (discharge pipe SH, forecasted port
SH) < 15°C
Every 20 sec.
or
• Forecasted port temperature 1 > 110°C
• Forecasted port temperature 2 > 130°C
• Discharge pipe temperature > 90°C
• Discharge pipe
temperature > 80°C
• Discharge pipe
temperature
≤
80°C
Discharge gas
temperature control
Intermediate
SH control
• The target discharge pipe
temperature is controlled to
be 90°C.
• Controlled for target
intermediate SH
(8 to 12°C)
Outdoor EV3
control
Operation of one
INV compressor
INV comp
STD compressor
• EV3: 480pls
• EV3 will be controlled using the difference in discharge
pipe temperatures of the INV and STD compressors.
43pls
≤
EV3
≤
480pls
