ESIE04-01
Outdoor Unit Functional Concept
Part 2 – Functional Description
2–57
3
2
4
5
1
3.4.2
General Expansion Valve Control
Outline
After the start up control function has been terminated the general expansion valve control function will
regulate the expansion valve opening in function of the target suction SH value (= superheat at
evaporator outlet).
The actual discharge SH value will be used to set the target suction SH value during operation.
The measured suction SH value will be used to control the opening of the expansion to the target
suction SH value.
Details
When the unit is in cooling or heating operation the opening of the expansion valve will be controlled
in order to keep the amount of superheat at the evaporator outlet constant. This way the evaporator
can be used at maximum efficiency under all conditions. The initial target heat exchanger outlet
superheat value = 5°C.
The target heat exchanger outlet superheat value can be increased in case the discharge superheat
value decreases.
The target heat exchanger outlet superheat value can be decreased in case the discharge superheat
value increases.
Control
During "General expansion valve control" 2 parameters will be used to control the actual expansion
valve opening degree:
1
Target superheat amount :
When the target heat exchanger outlet superheat > actual heat exchanger outlet superheat
→
the
expansion valve will close.
When the target heat exchanger outlet superheat < actual heat exchanger outlet superheat
→
the
expansion valve will open.
The superheat amount is checked every 10 seconds.
2
Frequency change: At the time of compressor frequency change, the expansion valve opening will
be changed with a fixed value. This value will be in function of the amount of compressor frequency
change.
Calculations
The heat exchanger outlet superheat value is calculated from the saturated suction temperature Te
(using LP sensor) and the suction pipe temperature R4T : SH = R4T-Te.
The discharge superheat value is calculated from the saturated discharge temperature Td (HP value
calculated out of PI, frequency and LP) and the discharge pipe temperature R3T : SH = R3T-Td.
RZQ - Final.book Page 57 Wednesday, September 8, 2004 8:40 AM
Summary of Contents for RZQ71~125B7V3B
Page 1: ...Service Manual ESIE04 01 RZQ71 125B7V3B Sky Air Inverter R 410A B series ...
Page 2: ......
Page 24: ...ESIE04 01 1 2 Part 1 System Outline 3 1 1 5 ...
Page 32: ...General Outline Outdoor Units ESIE04 01 1 10 Part 1 System Outline 3 1 1 4 5 ...
Page 64: ...General Outline Indoor Units ESIE04 01 1 42 Part 1 System Outline 3 1 1 4 5 ...
Page 76: ...Specifications ESIE04 01 1 54 Part 1 System Outline 3 1 1 4 5 ...
Page 92: ...Functional Diagrams ESIE04 01 1 70 Part 1 System Outline 3 1 1 4 5 ...
Page 94: ...ESIE04 01 1 72 Part 1 System Outline ...
Page 122: ...Wiring Diagrams ESIE04 01 1 100 Part 1 System Outline 3 1 1 4 5 ...
Page 140: ...ESIE04 01 2 2 Part 2 Functional Description 3 1 2 5 ...
Page 162: ...General Functionality ESIE04 01 2 24 Part 2 Functional Description 3 1 2 4 5 ...
Page 200: ...Outdoor Unit Functional Concept ESIE04 01 2 62 Part 2 Functional Description 3 1 2 4 5 ...
Page 202: ...ESIE04 01 3 2 Part 3 Troubleshooting 3 1 3 5 ...
Page 288: ...Error Codes Outdoor Units ESIE04 01 3 88 Part 3 Troubleshooting 3 1 3 4 5 ...
Page 312: ...Additional Checks for Troubleshooting ESIE04 01 3 112 Part 3 Troubleshooting 3 1 3 4 5 ...
Page 314: ...ESIE04 01 4 2 Part 4 Commissioning and Test Run 3 1 4 5 ...
Page 356: ...ESIE04 01 5 2 Part 5 Disassembly and Maintenance 3 1 5 ...
Page 484: ...ESIE04 01 viii Index 3 1 4 5 ...