Daikin Ducted Type Indoor Unit FDMG30NUV2S

Abnormally high pressure level is mostly caused by the condenser side.

The following contents are provided by service engineer based on their field checks.

Further, the number is listed in the order of degree of influence.;

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>

Procedure for checking outdoor-outdoor unit transmission wiring for broken wires

Turn OFF the power supply to all equipment

Short circuit between the outdoor-outdoor unit terminal F1 and F2 in the 'Outdoor Unit A'

Conduct continuity checks between the transmission wiring terminal blocks F1 and F2 of the centralized remote controller using a multiple meter

Is there continuity between the said terminal blocks?

If there is no continuity, the transmission wiring may have broken wires.

Conduct continuity checks between the transmission wiring terminal blocks F1 and F2 of the unified ON/OFF controller

Conduct continuity checks between the outdoor-outdoor unit terminal of the 'Outdoor Unit E'

Conduct continuity checks between the outdoor-outdoor unit terminal of the 'Outdoor Unit D'

Check for Fan Motor Connector (Signal Line)

(2) With the fan motor connector disconnected, measure the resistance between each pin, then make sure that the resistance is more than the value mentioned in the following table.

(2) With the fan motor connector disconnected, measure the resistance between each pin, then make sure that the resistance is balanced in ±30%.

Check for Fan Motor Connector (Power Supply Line)

With the relay connector disconnected, measure the resistance between UVW phases of the connector (3 cores) at the motor side, then make sure that the resistance between each phase is balanced and not short-circuited.;

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.