SiUS371901EB
Outline of Control (Indoor Unit)
Part 4 Functions and Control
172
9.6 Control of Electronic Expansion Valve
Electronic expansion valves in indoor units have the functions of conducting superheating degree
control in cooling operation and subcooling degree control in heating operation. However, if the
indoor units receive any control command such as a protection control command or a special
control command from the outdoor unit, the units will give a priority to the control command.
Superheating degree control in cooling operation
This function is used to adjust the opening of the electronic expansion valve so that superheating
degree (SH), which is calculated from the detection temperature (Tg) of the gas pipe thermistor
(R3T) and the detection temperature (Tl) of the liquid temperature thermistor (R2T) of the indoor
unit, will come close to a target superheating degree (SHS).
At that time, correction to the superheating degree is made according to the differences (
Δ
T)
between set temperature and suction air temperature.
Normally 5°C (9°F).
As
Δ
T (Remote controller set temp. – Suction air temp.) becomes larger, SHS becomes lower.
As
Δ
T (Remote controller set temp. – Suction air temp.) becomes smaller, SHS becomes
higher.
Subcooling degree control in heating operation
This function is used to adjust the opening of the electronic expansion valve so that the high
pressure equivalent saturated temperature (Tc), which is converted from the detected pressure of
the high pressure sensor in the outdoor unit, and the subcooling degree (SC), which is calculated
from the detected temperature (Tl) of the liquid temperature thermistor (R2T) in the indoor unit, will
come close to the target subcooling degree (SCS).
At that time, corrections to the subcooling degree are made according to differences (
Δ
T) between
set temperature and suction air temperatures.
Normally 5°C (9°F).
As
Δ
T (Remote controller set temp. – Suction air temp.) becomes larger, SCS becomes lower.
As
Δ
T (Remote controller set temp. – Suction air temp.) becomes smaller, SCS becomes
higher.
SH = Tg – Tl
Where,
SH: Evaporator outlet superheating degree
Tg: Indoor unit gas pipe temperature (R3T)
Tl: Indoor unit liquid pipe temperature (R2T)
SHS: Target superheating degree
SHS (Target SH value)
SC = Tc – Tl
Where,
SC: Condenser outlet subcooling degree
Tc: High pressure equivalent saturated temperature detected by the high pressure sensor
Tl: Indoor unit liquid pipe temperature (R2T)
SCS: Target subcooling degree
SCS (Target SC value)
Содержание REYQ72-432XAYCU
Страница 1: ...Service Manual Heat Recovery 60 Hz REYQ72 456XATJU A REYQ72 456XAYDU A REYQ72 432XAYCU A SiUS371901EB ...
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Страница 456: ...Wiring Diagrams SiUS371901EB 449 Part 7 Appendix REYQ72 96 120XAYDU REYQ72 96 120XAYDA 2D119207C ...
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Страница 458: ...Wiring Diagrams SiUS371901EB 451 Part 7 Appendix REYQ72 96 120 144 168XAYCU REYQ72 96 120 144 168XAYCA 2D119209B ...
Страница 459: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 452 1 2 Indoor Unit FXFQ07 09 12 15 18 24 30 36 48TVJU 3D086460B ...
Страница 460: ...Wiring Diagrams SiUS371901EB 453 Part 7 Appendix BYCQ125BGW1 Self Cleaning Decoration Panel for FXFQ TVJU 3D076375A ...
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Страница 464: ...Wiring Diagrams SiUS371901EB 457 Part 7 Appendix FXDQ07 09 12 18 24MVJU C 3D050501C ...
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Страница 466: ...Wiring Diagrams SiUS371901EB 459 Part 7 Appendix FXMQ07 09 12 15 18 24 30 36 48 54PBVJU 3D093209B ...
Страница 468: ...Wiring Diagrams SiUS371901EB 461 Part 7 Appendix FXHQ12 24 36MVJU 3D048116C ...
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Страница 477: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 470 1 4 2 Multi Branch Selector Unit Standard Series BS4Q54TVJ 3D089123B ...
Страница 478: ...Wiring Diagrams SiUS371901EB 471 Part 7 Appendix BS6 8Q54TVJ 2D089122B ...
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Страница 480: ...Wiring Diagrams SiUS371901EB 473 Part 7 Appendix 1 4 3 Multi Branch Selector Unit Flex Series BSF4Q54TVJ 3D123904A ...
Страница 481: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 474 BSF6 8Q54TVJ 2D123905A ...