- 150 -
[
VII
Control ]
-5- Compressor Frequency Control <PUHY>
Depending on the capacity required, the frequency of the compressor is controlled to keep constant evaporation temper-
ature (0°C [32°F] = 0.71 MPa [103 psi]) during cooling operation, and condensing temperature (49°C [120°F] = 2.88 MPa
[418 psi]) during heating operation.
The capacity of the P72-P144 is controlled solely by the inverter-driven compressor, and the capacity of P168-P234 is con-
trolled by No.1 compressor (inverter) and No.2 compressor (constant capacity).
The following table shows the frequency change of the inverter compressor during normal operation.
(1) No. 2 compressor operation/stop (P168-P234 models only)
No.2 compressor changeover from stop to in-operation
When No.1 compressor does not meet the capacity requirement, No.2 compressor will start its operation.
No.2 compressor changeover from stop to in-operation
When an operation of both No.1 and No.2 compressors exceeds the capacity requirement, No.2 compressor will stop
its operation.
(2) Pressure limit
The maximum limit of high pressure (Pd) is set for each frequency level. If this limit is exceeded, the frequency will be
reduced every 30 seconds.
(3) Discharge temperature limit
The discharge temperature (Td) of the compressor in operation is detected, and if it exceeds the upper limit, the frequency
is reduced by 5 Hz.
Control is performed 30 seconds after compressor start-up and every 30 seconds thereafter.
Operating temperature is 115°C [239°F] .
(4) Periodic frequency control
Frequency control other than the ones performed at start-up, upon status change, and for protection is called periodic fre-
quency control (convergent control) and is performed in the following manner.
[Periodic control cycle]
Periodic control is performed after the following time has passed
30 seconds after either compressor start-up or the completion of defrost operation
30 seconds after frequency control based on discharge temperature or pressure limit
[The amount of frequency change]
The amount of frequency change is controlled to approximate the target value based on the evaporation temperature
(Te) and condensing temperature (Tc).
Model
Frequency/cooling
Frequency/heating
Speed
P72 model
20-53 Hz
20-59 Hz
3 Hz/second
P96 model
20-70 Hz
20-85 Hz
3 Hz/second
P108 model
20-77 Hz
20-98 Hz
3 Hz/second
P126 model
20-89 Hz
20-102 Hz
3 Hz/second
P144 model
20-103 Hz
20-103 Hz
3 Hz/second
P168 model
20-65 Hz
20-73 Hz
3 Hz/second
P192 model
20-78 Hz
20-84 Hz
3 Hz/second
P204 model
20-88 Hz
20-93 Hz
3 Hz/second
P216 model
20-98 Hz
20-105 Hz
3 Hz/second
P234 model
20-107 Hz
20-113 Hz
3 Hz/second
The maximum frequency during heating operation is affected by the outdoor air temperature to a certain extent.
Summary of Contents for PUHY-P168
Page 11: ... 2 ...
Page 23: ... 14 ...
Page 25: ... 16 ...
Page 38: ... 29 II Restrictions ...
Page 42: ... 33 II Restrictions ...
Page 46: ... 37 II Restrictions ...
Page 50: ... 41 II Restrictions ...
Page 54: ... 45 II Restrictions ...
Page 58: ... 49 II Restrictions ...
Page 75: ... 66 ...
Page 101: ... 92 ...
Page 111: ... 102 ...
Page 113: ... 104 ...
Page 127: ... 118 ...
Page 145: ... 136 ...
Page 147: ... 138 ...
Page 185: ... 176 ...
Page 187: ... 178 ...
Page 241: ... 232 ...
Page 243: ... 234 ...
Page 366: ... 357 IX Troubleshooting ...
Page 367: ... 358 ...
Page 369: ... 360 ...