Daikin Ducted Type Indoor Unit FDBT48PUV2S

Temperature differences must occur before or after the clogged points!

Replace the electronic expansion valve.

Blow a nitrogen gas, and then replace the refrigerant.

Replace the heat exchanger or distributor.

Collapsed pipe Replace the pipe.

Warning: This check requires trained personnel with PPE!

Enter the current pressure level

Is the pressure level above the normal range?

If pressure is above normal range, proceed with the following checks

Sign off on the high pressure check

As criteria for judging whether refrigerant is excessively charged or not, refer to the following operating conditions.

<Diagnosis of excessive refrigerant charging>

(1) Because high pressure rises due to excessive charging, overload control is carried out and capacity tends to run short.

(2) Considering pressure load, compressor discharge pipe temperature is low.

(3) Subcooling degree of condensate liquid becomes large. Therefore, temperature of blown air passing through subcooling part decreases in heating operation.;

Warning: Disconnect the thermistor from the PCB before proceeding

Thermistor disconnected from the PCB

Upload a photo of the table with the measured values

Check if the measured values correspond with the values in the table

Sign off on the thermistor check

As criteria for judging whether refrigerant is inadequate or not, refer to the following operating conditions.

<Diagnosis of inadequate refrigerant>

(1) As suction superheated degree increases due to refrigerant shortage, the electronic expansion valve tends to open (opens fully) in order to avoid overheat operation.

(2) In response to decreased evaporator capacity caused by refrigerant shortage, capacity is controlled in the inverter in order to maintain low pressure, which results in a decrease in frequency.

(3) Because of (1) and (2) above, the compressor frequency decreases despite a large difference (large load) between temperature set by the remote controller and suction air temperature, resulting that cooling capacity becomes unavailable.

(4) If refrigerant shortage worsens, the electronic expansion valve remains fully open and suction superheated degree further increases. In addition, as compressor frequency drops to the level of the lowest frequency (41 Hz), low pressure cannot be maintained

<Diagnosis of inadequate refrigerant>