Daikin VRV - WII, Service Manual

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Troubleshooting (OP: Unified ON/OFF Controller) SiUS30-604
254 Troubleshooting
In order to maintain low pressure,
frequency decreases due to
capacity control.
Reaches the lowest
frequency
With low outdoor air cooling
control, fan is controlled in
order to maintain high
pressure = Hunting in fact
When frequency reaches the
lowest level, low pressure cannot
be maintained.
High pressure drops as
compressor capacity
decreases.
In order to maintain low
pressure, frequency
decreases due to capacity
control.
Low pressure rises due to
large open degree of indoor
unit electronic expansion
valve. Frequency slightly
increases due to capacity
control.
Frequency decreases due
to droop control.
The open degree of the outside unit
electronic expansion valve increases.
The outside unit electronic
expansion valve opens fully.
Frequency increases. Discharges pipe or low
pressure droop control
Any one of electronic
expansion valves opens fully.
The open degree of the indoor unit
electronic expansion valve increases.
[CHECK 6] Check for inadequate refrigerant quantity
In case of the VRV, judgment must be made based on operation conditions in relation to pressure control and
electronic expansion valve control. Refer to the following criteria to make such decisions.
Diagnosis of inadequate refrigerant
(1) The superheated degree of suction gas increases and temperature of compressor discharge gas
rises.
(2) The superheated degree of suction gas increases and the electronic expansion valve slightly
opens.
(3) With low pressure, cooling capacity (heating capacity) is unavailable.
High pressure
Low pressure
Frequency
Cooling
å~áº
Heating
High pressure
Low pressure
Frequency
Maintains a certain
level of low pressure
Reaches the
lowest frequency
Maintains a certain
level of high
pressure
Adequate level
(Degree of inadequate refrigerant)
Increase in the degree of
inadequate refrigerant