Si20-701_B
Troubleshooting by Remote Controller
478
Check for Inadequate Refrigerant
As criteria for judging whether refrigerant is inadequate
or not, refer to the following operating conditions.
<Diagnosis of inadequate refrigerant>
In cooling operation
(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.
CHECK 12
