SiUS371901E
Outline of Control (Indoor Unit)
Functions and Control
148
9.7
Freeze-Up Prevention
Freeze-Up Prevention by Off Cycle (Indoor Unit)
When the temperature detected by the liquid pipe temperature thermistor of the indoor heat exchanger drops too
low, the unit enters freeze-up prevention control in accordance with the following conditions, and is also set in
accordance with the conditions given below. (Thermostat OFF)
When freeze-up prevention is activated, the electronic expansion valve is closed, the drain pump turns on and
the airflow rate is fixed to L tap. When the following conditions for cancelling are satisfied, it will reset.
Conditions for starting:
Liquid pipe temperature
≤
– 1°C (30.2°F) (for total of 40 minutes)
or
Liquid pipe temperature
≤
– 5°C (23°F) (for total of 10 minutes)
Condition for cancelling:
Liquid pipe temperature
≥
+7°C (44.6°F) (for 10 minutes continuously)
Concept of freeze-up prevention control
System avoids freeze-up prevention
· For comfort, system avoids unnecessary thermostat ON/OFF
· For ensuring compressor reliability, system avoids unnecessary compressor ON/OFF
When freeze-up prevention control starts, system makes sure the frost is completely removed.
· System avoids water leakage.
Normal operation
Start
Cancel
Liquid pipe
temperature
Start
Cancel
Normal operation
–
5
ºC
(23˚F)
0
ºC
(32˚F)
+
7
ºC
(44.6˚F)
–
1
ºC
(30.2˚F)
t1
t2
t3
t4
0
ºC
(32˚F)
+
7
ºC
(44.6˚F)
10 min.
OR
10 min.
10 min.
t
>
40
minutes
Freeze-up prevention control
Forced OFF by thermostat
Freeze-up prevention control
Forced OFF by thermostat
Summary of Contents for REYQ72-456XATJU
Page 415: ...SiUS371901E Wiring Diagrams Appendix 402 REYQ144 168XATJU 2D119206A ...
Page 416: ...Wiring Diagrams SiUS371901E 403 Appendix REYQ72 96 120XAYDU 2D119207B ...
Page 417: ...SiUS371901E Wiring Diagrams Appendix 404 REYQ144 168XAYDU 2D119208B ...
Page 418: ...Wiring Diagrams SiUS371901E 405 Appendix REYQ72 96 120 144 168XAYCU 2D119209A ...
Page 421: ...SiUS371901E Wiring Diagrams Appendix 408 FXZQ05 07 09 12 15 18TAVJU 3D110443A ...
Page 423: ...SiUS371901E Wiring Diagrams Appendix 410 FXEQ07 09 12 15 18 24PVJU 3D098557A ...
Page 426: ...Wiring Diagrams SiUS371901E 413 Appendix FXMQ07 09 12 15 18 24 30 36 48 54PBVJU 3D093209B ...
Page 428: ...Wiring Diagrams SiUS371901E 415 Appendix FXHQ12 24 36MVJU 3D048116C ...
Page 429: ...SiUS371901E Wiring Diagrams Appendix 416 FXAQ07 09 12 18 24PVJU C 3D075354D ...
Page 435: ...SiUS371901E Wiring Diagrams Appendix 422 VAM1200GVJU 3D073270D ...
Page 437: ...SiUS371901E Wiring Diagrams Appendix 424 1 4 2 Multi Branch Selector Unit BS4Q54TVJ 3D089123B ...
Page 438: ...Wiring Diagrams SiUS371901E 425 Appendix BS6 8Q54TVJ 2D089122B ...
Page 439: ...SiUS371901E Wiring Diagrams Appendix 426 BS10 12Q54TVJ 2D089121B ...
Page 440: ...Revision History Month Year Version Revised contents 04 2019 SiUS371901E First edition ...