Daikin SkyAir Service Manual page 249

Troubleshooting by Remote Controller Display / LED Display
Check No.14
Check for Excessive Refrigerant Charging
As criteria for judging whether refrigerant is excessively charged or not, refer to the following
operating conditions.
<Diagnosis of excessive refrigerant charging>
In cooling operation
(1) Because high pressure rises due to excessive charging, overload control is carried out and
(2) Considering pressure load, compressor discharge pipe temperature is low.
(3) Subcooled degree of condensate liquid becomes large. Therefore, temperature of blown air
Cooling
High pressure
Low pressure
Compressor
frequency
Electronic
expansion valve
superheat degree
Discharge
superheat degree
High pressure
Low pressure
Compressor
expansion valve
superheat degree
superheat degree
238
capacity tends to run short.
passing through subcooled part decreases in heating operation.
Compressor frequency
increases in order to
maintain low pressure.
Suction Suction superheat degree is approx. 0 deg.
Adequate level
Heating
As compressor
frequency decreases,
low pressure rises.
frequency
Compressor frequency
decreases in order to
maintain high pressure.
Electronic
Suction Suction superheat degree is approx. 0 deg.
Discharge
Adequate level
As compressor
frequency decreases,
low pressure rises.
Maximum frequency
(Degree of excessive refrigerant charging)
(Degree of excessive refrigerant charging)
Compressor frequency
decreases due to high
pressure protection control
Minimum frequency
Electronic expansion valve
opening degree decreases
due to wet protection control
Minimum opening degree
Excessive charge
Minimum frequency
Electronic expansion valve
opening degree decreases
due to wet protection control
Minimum opening degree
Excessive charge
Troubleshooting
SiBE28-804