Defrost Control - Panasonic U-8ME2E8 Service Manual & Test Run Service Manual

9. Defrost Control

9. Defrost Control

(1) Type of Defrost Control
This system uses the following 2 defrosting systems.
System configuration
Only 1 outdoor unit in the refrigerant system
2 or more outdoor units in the refrigerant system
(2) Forced Conditions
Defrost does not begin again for 40 minutes of operation after defrost was once completed.
If the outdoor unit is stopped while defrosting due to protection control or another reason, then defrost control will
not start for a minimum of 10 minutes after restart occurs.
Even if all indoor units are stopped while defrosting, defrost control continues until it ends.
(3) Frost Detection
Frost detection does not occur for 5 minutes after operation starts.
Frost is detected when either condition 1 or 2 below is met.
Condition 1: L2 line shown in the figure below is detected twice for 4 minutes without interruption while the
compressor is operating.
Condition 2: L1 line shown in the figure below is detected for a total of 60 minutes while the compressor is
operating.
-25
Reverse cycle defrost
Outdoor unit cycle defrost
Minimum heat exchanger temperature °C
15 (Defrosting operation-end temperature)
-1
-3
-8
-10
Frost detection area below the bold lines L1 and L2
-25.5
-27.5
1 - 29
2WAY VRF SYSTEM
Control Functions - Outdoor unit
Name of defrost control
10
Ambient temperature°C
L1
L2
2WAY SYSTEM
Control Functions
1
unit: °C