2WAY VRF SYSTEM
Control Functions
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8. 4-Way Valve Adjustment Control
8. 4-Way Valve Adjustment Control
2WAY VRF SYSTEM
Control Functions
The first operation after turning on power supply to outdoor unit.
The mode of the system changes.
The purpose of this control is to change over the 4-way valve appropriately with big pressure difference.
This control is performed at the following conditions.
Cooling operation
* When the above operation is finished, normal operation starts at the horsepower determined by the indoor units
where thermostats are ON.
* When the above operation is finished, normal operation starts at the horsepower determined by the indoor units
where thermostats are ON.
The first operation after all outdoor units stopped for 60 minutes.
For 2 minutes
Indoor units
Control time
Outdoor units
MOV
RAP valve kit
Fan
All outdoor units operate at the maximum capacity.
MOV at all indoor units operate at a fixed pulse according to the indoor unit
capacity.
All indoor units operate in Cooling mode (OFF status).
Minimum 1 min - Maximum 20 min [until max. (pressure sensor temp.) 95°F (35°C)]
Indoor unit
s
Control time
Outdoor units
MOV
RAP valve kit
Fan
All outdoor units operate at the maximum capacity.
MOV at all indoor units operate at 250 pulses.
All indoor units operate in heating mode (ON status).
Heating operation
・
Stop and cooling (thermostat ON/OFF) operation of indoor units will be
followed the indoor unit control system.
・
Fan operation of indoor unit is changed to LL.
・
As for heating thermostat ON indoor units, follow the indoor unit control system.
・
Fan and heating (thermostat OFF) operation of indoor unit will be stopped.
・
The fan speed of heating thermostat OFF Concealed Duct - High Static type indoor
unit (Type E1) is changed to LL.
2WAY VRF SYSTEM
Control Functions
9. Defrost Control
(1) Type of Defrost Control
(2) Forced Conditions
This system uses the following 2 defrosting systems.
Defrost does not begin again for 40 minutes of operation after defrost was once completed.
(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:
-13 (-25)
Minimum heat exchanger temperature °F (°C)
50 (10)
Ambient temperature°F (°C)
Frost detection area below the bold lines L1 and L2
L1
L2
59 (15) (Defrosting operation-end temperature)
unit: °F (°C)
30.2 (-1)
26.6 (-3)
17.6 (-8)
14 (-10)
-13.9 (-25.5)
-17.5 (-27.5)
L1 line shown in the figure below is detected for a total of 60 minutes while the compressor is
operating.
Even if all indoor units are stopped while defrosting, defrost control continues until it ends.
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.
System configuration
Only 1 outdoor unit in the refrigerant system
2 or more outdoor units in the refrigerant system
Name of defrost control
Reverse cycle defrost
Outdoor unit cycle defrost
SM830237-07_北米向け2WAY_VRF.indb 30
18/06/19 18:55:34
