SiAF332111E Check
Part 6 Service Diagnosis 345
6.6 Refrigerant Overcharge Check
CHECK 6 In case of VRV systems, the only way to judge as the overcharge of refrigerant is with operating
conditions due to the relationship to pressure control and electronic expansion valve control.
As information for making a judgment, refer to the information below.
Diagnosis of refrigerant overcharge
1. High pressure rises. Consequently, overload control is conducted to cause insufficient
cooling capacity.
2. The superheating degree of suction gas lowers (or wet operation is performed).
Consequently, the compressor becomes lower in discharge pipe temperature despite of
pressure loads.
3. The subcooling degree of condensate rises.
Cooling
High pressure
Low pressure
Frequency
High pressure
gradually rises with
increase in
frequency.
Subcooling degree
becomes higher.
(Liquid connection
pipe temperature
lowers.)
Low pressure
rises due
to decreased
compressor output.
Higher degree of overcharge
(Degree of overcharge)
Proper amount
To maintain low pressure, frequency
increases under the capacity
control.
Frequency comes to
the minimum level.
High pressure
dropping control
(Low pressure is
maintained at a
constant level.)
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