Function Control; Electronic Expansion Valve Pi Control - Daikin SkyAir RZQ200 · 250C7Y1B Service Manual

SiBE26-701

2.4.4 Function Control

2.4.4.1 Compressor Step Control
In order to control capacity, the compressor operation is controlled according to the following
steps:
<RZQ200 · 250C>
*RZQ250C only (RZQ200C: STEP1~23, RZQ250C: STEP1~25)

2.4.4.2 Electronic Expansion Valve PI Control

When cooling/heating, PI control of electronic expansion valve is conducted to make heat
exchanger outlet subcool degree (SH) constant in order to utilize outdoor unit heat exchanger
(evaporator) fully.
SH=R4T-Te
[When slight wet operation]
Target heat exchanger outlet subcool degree
→
[When slight overheat operation]
Target heat exchanger outlet subcool degree
→
2.4.4.3 "Automatic Operation Mode" Control (PMV Control)
When selecting "Automatic Operation Mode" with the remote controller, conducts the most
comfortable operation in which you do not feel too cool or too hot.
Function and Operation
Step No. Comp. operation frequency
1
2
3
4
5
6
7
8
9 104Hz
10 110Hz
11 116Hz
12 124Hz
13 133Hz
Te: Low pressure equivalent saturation temperature (°C)
R4T: Suction pipe temperature (°C)
Electronic expansion valve closes
Electronic expansion valve opens
The value of target heat exchanger outlet subcool degree varies depending on change of
discharge pipe superheat degree of inverter compressor, etc.
Outdoor air temperature
Indoor air temperature
Remote controller set temperature
Step No.
52Hz 14
57Hz 15
62Hz 16
68Hz 17
74Hz 18
81Hz 19
88Hz 20
96Hz 21
22
23
24
25
>
Heat exchanger outlet subcool degree
<
Heat exchanger outlet subcool degree
Calculates and controls the
optimum indoor temperature
Outdoor Unit
Comp. operation frequency
143Hz
158Hz
165Hz
177Hz
189Hz
202Hz
210Hz
218Hz
232Hz
*248Hz
*266Hz
*280Hz
63