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2WAY SYSTEM
Control Functions-Outdoor Unit
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9. Defrost Control
9-1. Defrost Methods
This system uses the following 2 defrosting systems.
System employs
Defrost control method
1 outdoor unit in the refrigerant system
Reverse cycle defrost
2 or more outdoor units
in the refrigerant system
Outdoor unit cycle defrost
9-2. Constraint conditions
- Frost detection does not occur for 5 minutes after operation starts.
- Defrost does not begin again for 35 minutes of operation after defrost was once completed.
- If all indoor units are stopped while defrosting, or if the outdoor unit is stopped due to protection control or
another reason, then defrost control will not start for a minimum of 10 minutes after restart occurs.
9-3. Frost detection
(A) Frost detection does not occur for 5 minutes after operation starts.
(B) Frost is detected when either condition 1 or 2 below is met.
Condition 1: L2 line or below is detected twice, each time continuously for 4 minutes, when the compressor is
operating.
Condition 2: L1 line or below is detected for a total of 60 minutes when the compressor is operating.
–25
–23
–10
The frost detection area is
located under the thick lines
L2
L1
–3
–21.4
–8
–1
10
10
External temperature °C
Heat exchange liquid temperature °C
Defrosting operation
end temperature
(The end temperature
is different from the
above detection
temperature.)
SM830186-00̲2WAY ECO-i.indb 27
SM830186-00̲2WAY ECO-i.indb 27
2010/12/24 10:09:57
2010/12/24 10:09:57