Step Control Of Outdoor Unit Fans; Outdoor Unit Fan Control In Cooling Operation - Daikin RXYQ96PYDN Service Manual

Basic Control
function is used to exert PI control on the electronic expansion valve (Y1E or Y3E) so that the
evaporator outlet superheated degree (SH) will become constant.
SH = Tg - Te
Subcooling electronic expansion valve EVT control
In order to make the maximum use of the subcool heat exchanger, this function is used to exert PI
control on the electronic expansion valve (Y2E, Y5E or Y3E) so that the evaporator-side gas pipe
superheated degree (SH) will become constant.
SH = Tsh - Te
Refrigerant charge electronic expansion valve EVJ control
While in automatic refrigerant charge mode, this function is used to exert PI control on the opening
degree of the electronic expansion valve (Y2E or Y4E) in response to outdoor temperature and
close the valve after the completion of refrigerant charge.
For normal operation, fully open this electronic expansion valve.
6.4

Step Control of Outdoor Unit Fans

Used to control the revolutions of outdoor unit fans in the steps listed in table below, according to condition changes.
STEP No.
REYQ72P
0 0
1 285/255
2 315/285
3 360/330
4 430/400
5 590/560
6 690/660
7 820/790
8 920/890
9 920/890
Fan1/Fan2
* Figures listed above are all those controlled while in standard mode, which vary when the system is set to high static
pressure or capacity precedence mode.
6.5

Outdoor Unit Fan Control in Cooling Operation

While in cooling operation, if the outdoor temperature is low, this mode provides high-pressure
control using the outdoor unit fan to retain appropriate liquid pressure, thus ensuring refrigerant
194
Single type
REYQ96P REYQ120P
0 0
285/255 285/255
315/285 315/285
360/330 360/330
430/400 430/400
590/560 590/560
690/660 690/660
820/790 820/790
920/890 951/931
920/890 1020/990
Fan1/Fan2 Fan1/Fan2
SH : Evaporator outlet superheated degree (°F)
Tg : Suction pipe temperature (°F) detected by
the heat exchanger gas pipe thermistor
R2T.
Te : Low pressure equivalent saturated
temperature (°F)
SH: Evaporator outlet superheated degree (°F)
Tsh:Suction pipe temperature (°F) detected by
the subcool heat exchanger outlet
thermistor R5T
Te: Low pressure equivalent saturated
temperature (°F)
Fan revolutions (rpm)
REYQ144PTJU REMQ72P
0
285/255 350
360/315 370
395/365 400
480/440 450
560/530 540
760/730 610
960/930 680
1155/1125 710
1200/1170 796
Fan1/Fan2
SiUS34-801A_b
Multiple type
REMQ96P
0 0
350
370
400
450
560
680
710
750
821
VRVIII R-410A Heat Recovery 60Hz
REMQ120P
0
350
370
400
450
560
680
710
775
870