Panasonic U-4LE2E5 Service Manual & Test Run Service Manual page 35

8. Defrost Control
9. Defrost Control
(4) Heating Operation Set Time (Defrosting Operation Prohibiting Time)
When the heating operation time at system has exceeded "XX" minutes (35 minutes at initial setting), and at
least one unit satisfies the decision of defrosting, the defrosting operation is effective.
* XX is able to set in EEPROM of main outdoor unit.
EEPROM setting in main outdoor unit
CODE: A3
Setting No.
0
1
...
35
(factory preset code)
...
60
* 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).
(5) Defrost End Judgment Conditions
Defrost ends when either of the below defrost end judgment conditions is met.
Condition 1: The temperatures are 15°C or higher at all heat exchanger sensors installed on the outdoor
unit.
Condition 2: One minute has elapsed under the condition that the temperatures are 10°C or higher at all heat
exchanger sensors installed in the outdoor unit.
Condition 3: 13 minutes have elapsed.
(6) Reverse Cycle Defrost
If there is only 1 outdoor unit in the refrigerant system, a reverse cycle defrost will be carried out.
Defrost flow E: Evaporator operation
C: Condenser operation
E → C:
C → E:
Outdoor unit status
Compressor
4-way valve
Indoor unit Cooling mode
Heating mode
Time
It is possible to change the stopped time according to the setting.
For the maximum defrost time, see the table shown above.
XX
0 (minutes)
1 (minutes)
...
35 (minutes)
...
60 (minutes)
Switching evaporator operation to condenser operation
Switching condenser operation to evaporator operation
preparation
E → C
Operating
ON→OFF
Stopped C→E
Fan (only) C→E
Thermostat ON C→E
Thermostat OFF C→E
Thermostat ON C→E
Thermostat OFF C→E
40 seconds
Control Functions - Outdoor unit
Defrost Defrost in
progress
C
Operating
OFF
E
E
E
E
E
E
Maximum 15 minutes
1 - 25
2WAY VRF SYSTEM
Mini VRF SYSTEM
Control Functions
Defrost end
C → E
Stopped
OFF→ON
E → C
Defrost
E → C
end
E → C
judgment
E → C
E → C
E → C
1 minute
1