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Mini VRF SYSTEM
Trouble Diagnosis
6
3. Mini VRF Alarm Codes
3WAY SYSTEM
Trouble Diagnosis
4. 3WAY Alarm Codes
F16 Alarm
Alarm code
Alarm meaning
High pressure sensor has failure. (HPS)
(1) High-pressure sensor failure
(1) High-pressure sensor failure
(2) Failure to connect the connector to the Outdoor Unit Control PCB
Check the connector connected to the Outdoor Unit Control PCB
(3) Failure to open the service valve
Check the open/closed status of the service valve.
(6) Outdoor Unit Control PCB failure
(1) Replacement of high-pressure sensor
When replacing a high-pressure sensor, carry out after refrigerant recovering of outdoor unit.
(2) Replacing the Outdoor Unit Control PCB
(3) Correct malfunction of refrigerant cycle.
Open valve of outdoor unit.
During cooling: Not available in case of low outdoor temperature or adjusting the outdoor fan.
While both the compressors are operating under 12-step or 13-step in the fan mode,
high-pressure's saturation temperature indicates the outdoor temperature
+ around 15°C.
If the temperature is 5°C higher than the said temperature, over-charging might be
expected.
During heating: There is an indoor unit where refrigerant flow is poor (E1 temperature and discharge
temperature are low), and the mechanical valve of that unit is opened to 300 pulses
or more, and the E1 temperature is close to room temperature. However be aware
that this kind of data results often when there is a height difference between indoor
units. Reducing the amount of refrigerant will improve the refrigerant flow, however
reducing it too much will increase the likelihood of alarms related to low oil level
(scroll-side), the low pressure switch, and discharge temperature. Use caution.
Correct clogging.
In the case of refrigerant over-charging, recover appropriate amount of refrigerant.
Standards of over-charging
Install the pressure gauge at the high-pressure removal port of outdoor units and check for it.
Trouble is corrected: Outdoor Unit Control PCB failure
Trouble is not corrected: High-pressure sensor malfunction
The check items are the same as for a high-pressure sensor malfunction.
A normal PCB is needed to determine whether the problem is a PCB failure or a pressure sensor
malfunction. If an abnormality was found at the check items for a high-pressure sensor malfunction,
first try replacing the PCB and check again.
(4) Check for clogging of the refrigerant circuit. (5) Check for refrigerant over-charging.
When clogging or over-charging occurs, refrigerant is likely to accumulate in the outdoor unit (cooling)
and indoor unit (heating). Sudden rise in pressure at start may sometimes occur.
(2) Failure to connect the connector to the Outdoor Unit Control PCB
(3) Failure to open the service valve of the outdoor unit
(4) Clogged refrigerant circuit
(5) Refrigerant over-charging
(6) Outdoor Unit Control PCB failure
High-pressure sensor disconnected or open circuit
Check the sensor resistance value. (Use a tester and measure the resistance between sensor No. 1
and No. 3)
Resistance of less than 95kΩ indicates a short circuit or other trouble.
Resistance of 95kΩ - 105kΩ (high pressure sensor pin 1-3) is normal.
Resistance of more than 105k indicates an open circuit or other trouble.
Connect a gauge to the high-pressure outlet and check for changes in the value displayed by the
monitoring software, and for large deviation of the gauge pressure.
During heating, check whether the temperature is lower than the highest indoor-unit E1 temperature.
The pressure detected by the high-pressure sensor is the highest pressure in the system.
Therefore during heating the converted saturation temperature will never be lower than any
indoor-unit E1 temperature. During cooling this temperature will never be lower than the outdoor
unit liquid temperature.
High-pressure sensor detected over 3.6MPa continuously for 30 minutes while outdoor units stopped.
High-pressure sensor detected over 3.6MPa while outdoor units were operating. (In some cases, start
and stop may sometimes repeat due to pre-trip mode.)
Alarm conditions
Probable cause
Check
Correction
Example
Malfunction had occurred when the liquid, suction and discharge tubes were clogged together.
F16
F17 Alarm
Alarm code
F17
Alarm meaning
Low pressure sensor has failure. (LPS)
Alarm conditions
(1) Sensor short circuit
(2) Sensor open circuit
Probable cause
(1) Sensor malfunction (including connector)
(2) The Outdoor Unit Control PCB malfunction
Check
(1) Measure the sensor resistance. Check that the sensor is operating normally.
(2) Use a remote monitor or a PC monitor to check the temperature that is recognized by the
microcomputer.
Correction
—
Example
—
Notes
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F31 Alarm
Alarm code
F31
Alarm meaning
EEPROM on outdoor unit PCB has failure.
Alarm conditions
(1) Non-volatile memory is not present when power initialization occurs.
(2) Read values do not match after writing to non-volatile memory is complete.
Probable cause
(1) Memory was not inserted after the Outdoor Unit Control PCB was replaced.
(2) The lifetime of the non-volatile memory has been reached.
(3) Non-volatile memory is installed incorrectly (wrong direction, bent pins, etc.).
Check
(1) Check the non-volatile memory on the Outdoor Unit Control PCB.
Correction
—
Example
—
Notes
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H01 Alarm (U-4LE2E5, U-5LE2E5, U-6LE2E5)
Alarm code
H01
Alarm meaning
Compressor primary current is overcurrent.
Alarm conditions
Compressor (INV) primary current detected overcurrent higher than 32.2 (A).
Probable cause
(1) Wiring failure
(2) Power supply voltage malfunction (sudden-voltage-drop)
(3) The Outdoor Unit Control PCB or the HIC PCB failure.
Check
(1) Wiring failure
Forgot to connect the wires L, N. Check whether the terminals are connected correctly.
(2) Check the power supply voltage.
Correction
(1) Wiring failure
Correct the disconnection and wiring failure.
(2) Correct the power supply voltage.
(3) Replace the Outdoor Unit Control PCB or the HIC PCB.
Example
—
Notes
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H01 Alarm (U-4LE2E8, U-5LE2E8, U-6LE2E8)
Alarm code
H01
Alarm meaning
Compressor primary current is overcurrent.
Alarm conditions
Compressor (INV) primary current detected overcurrent higher than 14.0 (A).
Probable cause
(1) Wiring failure
(2) Power supply voltage malfunction (sudden-voltage-drop)
(3) The Outdoor Unit Control PCB or the HIC PCB failure.
Check
(1) Wiring failure
Forgot to connect the wires L1, L2, L3. Check whether the terminals are connected correctly.
(2) Check the power supply voltage.
Correction
(1) Wiring failure
Correct the disconnection and wiring failure.
(2) Correct the power supply voltage.
(3) Replace the Outdoor Unit Control PCB or the HIC PCB.
Example
—
Notes
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SM830258-01_欧州向け_1fan_mini_VRF.indb 11
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