VRV in General
Si30-408
118
Cases for Examination
1.15 Inverter Compressor Fails in a Short Period.
Applicable
Models
VRV in general
Condition
Inverter compressor for the specific outdoor unit fails due to faulty insulation.
Since seizure has occurred on the metal sliding section and remaining amount of refrigerant oil
is proper, in terms of malfunction mode the failure has occurred by the refrigerant oil that was
diluted through wet operation.
Cause
Detecting temperature of the gas pipe thermistor of outside air processing unit was 106°C being
different from the specified resistance. It caused to fully open the electronic expansion valve
mounted to the indoor unit and resulted in backflow of liquid.
(Indoor units of VRV set to stop operation after completion of the day's work, however, the
outside air processing unit set to operate around the clock.)
Measure
Recovers by replacing the EV drive section of the outside air processing unit.
Point of
Diagnosis
1. Use a service checker type III and check whether the superheated degree control of the
indoor unit is normal.
2. If the above checker is not available, use a remote controller to check.
(When replacing the compressor, locate the cause of fault of the compressor.)
1.16 Heating Operation of All Indoor Units is Faulty.
Applicable
Models
VRV in general
Condition
Heating operation of all indoor units is faulty though the operating capacity of indoor units is
small and all units are operating.
However, high-pressure of the outdoor units has reached the target value of 1.7MPa and
stabilized.
Temperature of liquid pipe and the one of gas pipe of indoor units are equivalent to indoor
temperature.
Cause
High-pressure gas flowed into the receiver due to leakage of the check valve in the receiver gas
releasing circuit. It caused the rise of liquid pressure and eliminated the differential pressure
from the high-pressure. Consequently the liquid accumulated due to improper amount of
circulating refrigerant at the electronic expansion valve of indoor unit and drop in discharge air
temperature occurred.
Measure
Recovers by replacing the corresponding check valve.
Point of
Diagnosis
