Basic Control
SiUS281117
Function and Control
35
RZR36/42P, RZQ36/42P
Note:
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).
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.
STn
INV.
(Full-load)
INV.
(Unload)
STn
INV.
(Full-load)
INV.
(Unload)
STn
INV.
(Full-load)
INV.
(Unload)
1
36.0Hz
11
80.0Hz
21
140.0Hz
2
39.0Hz
12
86.0Hz
22
146.0Hz
3
43.0Hz
13
92.0Hz
23
152.0Hz
4
47.0Hz
14
98.0Hz
24
158.0Hz
5
52.0Hz
15
104.0Hz
25
164.0Hz
6
52.0Hz
57.0Hz
16
110.0Hz
26
170.0Hz
7
57.0Hz
64.0Hz
17
116.0Hz
27
175.0Hz
8
62.0Hz
71.0Hz
18
122.0Hz
28
180.0Hz
9
68.0Hz
78.0Hz
19
128.0Hz
29
185.0Hz
10
74.0Hz
20
134.0Hz
30
190.0Hz
31
195.0Hz
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.
SH = Ts1 - Te
SH: Evaporator outlet superheated degree
Ts1: Suction pipe temperature detected by
thermistor
Te: Low pressure equivalent saturation temperature
SH = Tsh
- Te
SH: Evaporator outlet superheated degree
Tsh: Suction pipe temperature detected by
thermistor
Te: Low pressure equivalent saturation
temperature
