2WAY SYSTEM
Control Functions - Outdoor unit
1 - 30
1
9. Defrost Control
2WAY VRF SYSTEM
Control Functions
(4)
When the heating operation time at system has exceeded “XX” minutes (40 minutes at initial setting), and at
least one unit satisfies the decision of defrosting, the defrosting operation is effective.
Heating Operation Set Time (Defrosting Operation Prohibiting Time)
(5)
Defrost ends when either of the below defrost end judgment conditions is met.
Defrost End Judgment Conditions
(6)
If there is only 1 outdoor unit in the refrigerant system, a reverse cycle defrost will be carried out.
It is possible to change the stopped time according to the setting.
For the maximum defrost time, see the table shown above.
Reverse Cycle Defrost
* XX is able to set in EEPROM of main outdoor unit.
* Defrost control is also performed at outdoor units where the outdoor unit heat exchanger is not functioning as
an evaporator (such as stopped outdoor units).
EEPROM setting in main outdoor unit
CODE: A3
Setting No.
25
30
...
XX
25 (minutes)
40 (minutes)
(at factory shipment)
30 (minutes)
...
40
Condition 1: The temperatures are 15°C or higher at all heat exchanger sensors installed on the outdoor
unit.
Condition 2: 15 minutes have elapsed. (Reverse cycle defrost)
18 minutes have elapsed. (Outdoor unit cycle defrost)
Defrost flow E:
C:
Evaporator operation
Condenser operation
E → C:
C → E:
Switching evaporator operation to condenser operation
Switching condenser operation to evaporator operation
Indoor unit
Cooling mode
Heating mode
Defrost
preparation
Defrost in
progress
Defrost
end
judgment
Defrost end
Thermostat ON EC→E E → C
Thermostat OFF EC→E
E → C
Thermostat ON EC→E E → C
Fan (only) EC→E
E → C
Thermostat OFFEC→E
E → C
Compressor OperatingStopped Stopped
4-way valve OFFON→OFF OFF→ON
Stopped EC→E
E → C
Outdoor unit status CE →
→ E
TimeMaximum 15 minutes1 minute 1 minute
SM830253-00_欧州2way7_SM-TRSM.indb 30 16/08/26 19:23:19
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