Electronic Expansion Valve Pi Control - Daikin SkyAir RZQ-P Series Service Manual

SiUS28-902_B
RZR36/42P, RZQ36/42P
STn INV(Fullload) INV(Unload)
1
2
3
4
5
6 52.0Hz
7 57.0Hz
8 62.0Hz
9 68.0Hz
10 74.0Hz
 Compressors may operate in a pattern other than those listed in above tables subject to the operating conditions.
Selection of full load operation to/from unload operation is made with the unload circuit solenoid valve (Y3S=SVUL).
The full load operation is performed with the SVUL set to OFF, while the unload operation is performed with the
SVUL set to ON.
2.3

Electronic Expansion Valve PI Control

Main Electronic Expansion Valve EV1 Control
Carries out the electronic expansion valve (Y1E) PI control to maintain the evaporator outlet
superheated degree (SH) at constant during heating operation to make maximum use of the
outdoor unit heat exchanger (evaporator).
SH = Ts1 - Te
The optimum initial value of the evaporator outlet superheated degree is 9°F, but varies
depending on the discharge pipe superheated degree of inverter compressor.
Subcooling Electronic Expansion Valve EV3 Control
Makes PI control of the electronic expansion valve (Y3E) to keep the superheated degree (SH)
of the outlet gas pipe on the evaporator side for the full use of the subcooling heat exchanger.
SH = Tsh- Te
Function
STn INV(Fullload) INV(Unload)
36.0Hz 11
39.0Hz 12
43.0Hz 13
47.0Hz 14
52.0Hz 15
57.0Hz 16
64.0Hz 17
71.0Hz 18
78.0Hz 19
20
80.0Hz
86.0Hz
92.0Hz
98.0Hz
104.0Hz
110.0Hz
116.0Hz
122.0Hz
128.0Hz
134.0Hz
SH: Evaporator outlet superheated degree
Ts1: Suction pipe temperature detected by
thermistor
Te: Low pressure equivalent saturation temperature
SH: Evaporator outlet superheated degree
Tsh: Suction pipe temperature detected with the
thermistor
Te: Low pressure equivalent saturation
temperature
Basic Control
STn INV(Fullload) INV(Unload)
21 140.0Hz
22 146.0Hz
23 152.0Hz
24 158.0Hz
25 164.0Hz
26 170.0Hz
27 175.0Hz
28 180.0Hz
29 185.0Hz
30 190.0Hz
31 195.0Hz
15