Daikin FTXP20-71L, Service Manual

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4 | Third party components
Service manual
146
ATXP20~35 + FTXP20~71 + ARXP20~35 + RXP20~71
Split Comfora R32
ESIE18-01E – 2023.01
To check if the refrigerant circuit is correctly charged
Due to the relationship to pressure control and electronic expansion valve control,
the amount of refrigerant needs to be examined according to operating conditions.
Refer to the procedures shown below for correct examination.
Refrigerant overcharge diagnosis
1 High pressure rises. Consequently, overload control is conducted to cause
insufficient cooling capacity.
2 The superheated degree of suction gas lowers (or the wet operation is
performed). Consequently, the compressor consumes more power and is
noisy (before over‑current relay trips).
3 The subcooling degree of refrigerant in liquid form rises (values >4~5K are
NOT normal).
Cooling
Proper amount Further overcharge
(Degree of overcharge)
To maintain low pressure, operating
frequency increases on the capacity control.
(Low pressure is maintained
at a certain level.)
High pressure drooping control
Operating frequency comes to
the lowest level.
Subcooling degree becomes
higher. (The temperature of
liquid connection piping
becomes lower.)
High pressure gradually rises with
increasing operating frequency.
Low pressure rises with lowering
compressor output.
Operating
frequency
Low
pressure
High
pressure
Heating
Proper amount Higher degree of
overcharge
(Degree of overcharge)
To maintain high pressure, frequency
decreases under the capacity control.
Low pressure drops due to
closed outdoor unit
electronic expansion valve.
High pressure drops or rises
immediately after the
overload control is complete.
Low pressure rises
due to decreased
frequency.
Frequency comes to
the minimum level.
The electronic expansion valve
is closed due to the overload control.
Frequency
Low
pressure
High
pressure
(High pressure is
maintained at a
constant level.)
Refrigerant shortage diagnosis
1 The superheated degree of suction gas rises. Consequently, the compressor
discharge gas temperature becomes higher than normal.