Fault code ECOi ME1 & MF1

1. The power supply to the indoor unit was switched off after the first communication
2. An interruption or short circuit occurred in the control line between the units after the initial communication was completed

The automatic address setting is carried out on another outdoor unit.

The number of indoor units was too few when the automatic address setting was carried out.

1. The number of indoor units that were set on the outdoor unit circuit board using the indoor unit quantity setting switch (S004, S005) is higher than the set number.
2. The control lines between the units are interrupted.

1. Refer to the maintenance material for the test run and check the number of indoor units set SW (S004, S005).
2. Check the control lines between the units on the indoor and outdoor units.

After you adjust the quantity of the indoor unit or the wiring between the control units, carry out the automatic address setting again.

• The number of indoor units was too high when the automatic address setting was carried out.
• After the initial communication, an unrecognised unit was recognised.

• The number of indoor units that were set on the outdoor unit circuit board using the indoor unit volume setting switch (S004, S005) is less than the set number.
• The control lines between the units are incorrectly wired.

1. Refer to the maintenance material for the test run and check the number of indoor units set.
2. Check the control lines between the units on the indoor and outdoor units.

1. The control lines between the units from the outdoor unit to the indoor units have been interrupted.
2. Serial port 1 (CN001) is not connected to the outdoor unit.
3. The power supply is switched off on all indoor units in the system.

1. Check if the control lines between the units from the outdoor unit to the indoor units are interrupted.
2. Check whether the serial connector 1 (CN001) is disconnected from the outdoor unit.
3. Check the power supply on the indoor units.

1. After the first communication was completed, the control wiring between the main and secondary outdoor units was interrupted.
2. After the first communication was completed, the power supply to the outdoor unit was turned off.

1. The outdoor unit quantity is set incorrectly.
2. The main-secondary control wiring of the outdoor unit is interrupted.

1. Recheck the outdoor unit quantity settings.
2. Check the wiring of the main and sub control of the outdoor unit.

1. Correct the incorrect quantity setting of the outdoor unit.
2. Repair the main-secondary control cable of the outdoor unit.

Restoration after this alarm is automatic (if the set outdoor unit quantity matches the number of outdoor units recognised by the main-secondary control wiring of the outdoor unit).

1. After the first communication processes were completed, the main auxiliary control line of the outdoor unit was interrupted.
2. After the first communication was completed, the RC connector was removed. (3) The power supply on the outdoor unit (main unit) is switched off.

1. Check the wiring of the main and secondary control of the outdoor unit.
2. Check the RC connections.
3. Check power supply to the outdoor unit (main unit).

1. Repair the main sub control cables of the outdoor unit.
2. Correct the RC connector.
3. Turn on the outdoor unit (main unit).

It happens:

• An error occurred when rewriting the microcomputer
• If the device is switched off while rewriting the microcomputer.
• When the wiring between the circuit board and the ROM burner is not connected.

1. Rewrite the microcomputer.
2. Switch on again

1. Discharge temp. of 100°C or higher was found 20 minutes or more after the compressor stopped.
2. Discharge temp. of 70°C or higher was found after all compressors were stopped for 60 minutes or longer.
3. A / D step is 10 steps or less (short circuit).

1. Malfunction of the sensor Malfunction of the sensor element The sensor wiring is partially disconnected, which leads to increased electrical resistance. This alarm does not occur if the wiring is broken or the plug is not connected to the outdoor unit PCB.
2. Wiring crossed or installation error The outlet temperature sensor of this compressor is connected to the outlet pipe of the other compressor. The connector for the outlet temperature sensor of the problematic compressor is connected to the PCB connector of the outdoor unit for the other compressor.
3. PCB error of the outdoor unit
4. The check valve on the outlet pipe of this compressor is wet.
5. A short circuit in the air around the outdoor unit has increased the ambient temperature of the outdoor unit and the cooling effects after the compressor was switched off.
6. There is a cause that leads to a P03, P17 or P02 alarm.
7. Electrical noise

1. Sensor malfunction and outdoor unit circuit board failure
Problem:

    Always shows a high temperature.
    When monitoring software or other means of monitoring are used, the discharge temperature sometimes fluctuates suddenly and erratically.
    In some cases, the exact temperature may not be known even if monitoring software is used.

Test:

    Wiggle the sensor and check if the error persists.
    Check whether the connector is partially disconnected from the circuit board.
    • An F04 alarm is not triggered if the connector is completely removed (circuit is open).
    If the cause is still uncertain, check the following to determine if a sensor or PCB error has occurred.
    Step 1:
    Connect the other compressor discharge sensor, or a discharge sensor that did not have an F04 alarm, to the connector for that compressor on the circuit board. Measure the temperature at the same point (in a place with small temperature fluctuations) and check whether there is a temperature difference.
    Difference → A circuit board or sensor error is possible.
    No difference → Circuit board and sensor are normal.
    Step 2:
    If a malfunction was detected in stage 1, connect the faulty compressor sensor to the other compressor connector on the circuit board or to the circuit board connector of a unit that did not have an F04 alarm. Measure the temperature at the same point (in a place with small temperature fluctuations) and check whether there is a temperature difference.
    Difference → Sensor error.
    No difference → PCB error.
    • It is advisable to have an outlet temperature sensor at hand at this time.

2. Crossed wiring or installation error
Trouble:

Although the other compressor is operating and this compressor is stopped, the outlet temperature of the other compressor does not rise and the outlet temperature of this compressor increases.
• The outlet temperature remains high immediately after the compressor stops. Wait some time after the compressor stops and observe.

Although the other compressor is operating and this compressor is stopped, the outlet temperature of the other compressor does not rise and the outlet temperature of this compressor increases.
• The outlet temperature remains high immediately after the compressor stops. Wait some time after the compressor stops and observe.

Check:

Check for wiring and installation errors.

3. Leakage at the outlet pipe check valve
Trouble:

Although the other compressor is operating and this compressor is stopped, the outlet temperature of this compressor rises along with the temperature of the other compressor.

4. The ambient temperature around the outdoor unit, when it is stopped, is 43°C or more.

5. If after checking the above items the cause is still unknown, it is possible that electrical noise is the cause of the problem. It is necessary to provide a line filter or take other countermeasures against noise.

1.     Replace the sensor.
2.     Replace the outdoor unit circuit board.
3.     Carry out noise protection measures.
4.     Repair refrigerant hose.
5.     Adjust the amount of refrigerant.
6.     Rectify the error.

1. Discharge temp. of 100°C or higher was found 20 minutes or more after the compressor stopped.
2. of 70°C or higher was found after all the compressors were stopped for 60 minutes or longer.
3. A / D step is 10 steps or less (short circuit).

1. Malfunction of the sensor Malfunction of the sensor element The sensor wiring is partially disconnected, which leads to increased electrical resistance. This alarm does not occur if the wiring is broken or the plug is not connected to the outdoor unit PCB.
2. Wiring crossed or installation error The outlet temperature sensor of this compressor is connected to the outlet pipe of the other compressor. The connector for the outlet temperature sensor of the problematic compressor is connected to the PCB connector of the outdoor unit for the other compressor.
3. PCB error of the outdoor unit
4. The check valve on the outlet pipe of this compressor is wet.
5. A short circuit in the air around the outdoor unit has increased the ambient temperature of the outdoor unit and the cooling effects after the compressor was switched off.
6. There is a cause that leads to a P03, P17 or P02 alarm.
7. Electrical noise

1. Sensor malfunction and outdoor unit circuit board failure
Problem:

    Always shows a high temperature.
    When monitoring software or other means of monitoring are used, the discharge temperature sometimes fluctuates suddenly and erratically.
    In some cases, the exact temperature may not be known even if monitoring software is used.

Test:

    Wiggle the sensor and check if the error persists.
    Check whether the connector is partially disconnected from the circuit board.
    • An F04 alarm is not triggered if the connector is completely removed (circuit is open).
    If the cause is still uncertain, check the following to determine if a sensor or PCB error has occurred.
    Step 1:
    Connect the other compressor discharge sensor, or a discharge sensor that did not have an F04 alarm, to the connector for that compressor on the circuit board. Measure the temperature at the same point (in a place with small temperature fluctuations) and check whether there is a temperature difference.
    Difference → A circuit board or sensor error is possible.
    No difference → Circuit board and sensor are normal.
    Step 2:
    If a malfunction was detected in stage 1, connect the faulty compressor sensor to the other compressor connector on the circuit board or to the circuit board connector of a unit that did not have an F04 alarm. Measure the temperature at the same point (in a place with small temperature fluctuations) and check whether there is a temperature difference.
    Difference → Sensor error.
    No difference → PCB error.
    • It is advisable to have an outlet temperature sensor at hand at this time.

2. Crossed wiring or installation error
Trouble:

Although the other compressor is operating and this compressor is stopped, the outlet temperature of the other compressor does not rise and the outlet temperature of this compressor increases.
• The outlet temperature remains high immediately after the compressor stops. Wait some time after the compressor stops and observe.

Although the other compressor is operating and this compressor is stopped, the outlet temperature of the other compressor does not rise and the outlet temperature of this compressor increases.
• The outlet temperature remains high immediately after the compressor stops. Wait some time after the compressor stops and observe.

Check:

Check for wiring and installation errors.

3. Leakage at the outlet pipe check valve
Trouble:

Although the other compressor is operating and this compressor is stopped, the outlet temperature of this compressor rises along with the temperature of the other compressor.

4. The ambient temperature around the outdoor unit, when it is stopped, is 43°C or more.

5. If after checking the above items the cause is still unknown, it is possible that electrical noise is the cause of the problem. It is necessary to provide a line filter or take other countermeasures against noise.

1.     Replace the sensor.
2.     Replace the outdoor unit circuit board.
3.     Carry out noise protection measures.
4.     Repair refrigerant hose.
5.     Adjust the amount of refrigerant.
6.     Rectify the error.

1. A / D step is 10 steps or less (short circuit).
2. A / D step is 1014 steps or more (open circuit).

1. Sensor malfunction (including connector)
2. PCB fault

1. Measure sensor resistance. Check whether the sensor is functioning normally.
2. Use a remote control or PC monitor to check the temperature detected by the microcomputer.

1. A / D step is 10 steps or less (short circuit).
2. A / D step is 1014 steps or more (open circuit).

1. Sensor malfunction (including connector)
2. PCB fault

1. Measure sensor resistance. Check whether the sensor is functioning normally.
2. Use a remote control or PC monitor to check the temperature detected by the microcomputer.

1. A / D step is 10 steps or less (short circuit).
2. A / D step is 1014 steps or more (open circuit).

1. Sensor malfunction (including connector)
2. PCB fault

1. Measure sensor resistance. Check whether the sensor is functioning normally.
2. Use a remote control or PC monitor to check the temperature detected by the microcomputer.

1. A / D step is 10 steps or less (short circuit).
2. A / D step is 1014 steps or more (open circuit).

1. Sensor malfunction (including connector)
2. PCB fault

1. Measure sensor resistance. Check whether the sensor is functioning normally.
2. Use a remote control or PC monitor to check the temperature detected by the microcomputer.

• High pressure SW activated even though the detected pressure was lower (3.03 MPa or less) than the high pressure SW activation pressure: Undershift
• High pressure SW could not be activated even though the detected pressure was higher (3.43 MPa or higher)) than the high pressure SW activation pressure: Overthrust
• The saturation temperature at the detected pressure is continuously 5°C or more below the highest internal temperature E1 for 30 minutes.
• High pressure sensor not connected or open circuit.

1. High pressure sensor malfunction
2. Error connecting the connector to the PCB of the outdoor unit
3. Opening of the service valve failed
4. Blocked hose
5. Valve leakage
6. Overloading
7. Circuit board fault of the outdoor unit
8. Electrical noise

1. High pressure sensor failure

•     Check the sensor resistance value. (Use a tester and measure the resistance between sensor # 1 and # 3)
•     A resistance less than 10 kΩ indicates a short circuit or other problem.
•     A resistance of 10 kΩ - 200 kΩ is normal. A resistance of more than 200 kΩ indicates a disconnection or other malfunction.
•     Connect a pressure gauge to the high pressure outlet and check whether the value displayed by the monitoring software has changed and whether the pressure gauge pressure deviates significantly.
•     During heating, check whether the temperature is below the highest temperature of the indoor unit E1.

    * The pressure detected by the high pressure sensor is the highest pressure in the system. Therefore, the converted saturation temperature during heating will never be lower than the internal E1 temperature. During cooling, this temperature is never lower than the outdoor unit fluid temperature.

2. The service valve cannot be opened, the hoses are blocked, the valve is leaking and it is overloaded.
In all of these cases, an alarm occurs when there are rapid pressure fluctuations and the tracking of the detected pressure is poor.

• Check the opening/closing status of the valve.
• Check whether the hose is blocked.    To check for blocking, disconnect the high pressure sensor from the circuit board and check that the high pressure switch is activated.
• Check the valve for leaks and overload.
• If a valve leak or overload occurs, refrigerant is likely to collect in the outdoor or indoor units, which leads to a sudden increase in pressure at start-up, which occurs before the refrigerant is discharged into the heat exchanger.

    * The representative valves to be checked are the fluid valves and the mechanical valves.

3. Outdoor unit PCB failure

• The check points are the same as in the case of a malfunction of the high pressure sensor.
  A normal PCB is needed to determine if the problem is a PCB fault or malfunction of the pressure sensor. If an abnormality in the high pressure sensor malfunction is found in the test pieces, replace the circuit board and check it again.

      The problem has been solved: Outdoor unit circuit board error
      The fault is not eliminated: High pressure sensor fault

1. Replace the high pressure sensor.
Caution:
Because a Schrader type valve is used to connect the high pressure sensor, it can be removed and replaced. However, the high pressure sensor can easily be damaged by high voltage. So take precautions regarding static electricity.

2. Replace the circuit boards.

3. Correct the points where problems occur in the refrigeration circuit.

    Correct areas where blockages or leaks have occurred.
    Remove refrigerant if overloaded. (Set refrigerant amount).
    ∗ Instructions regarding overloading
    Be sure to connect the pressure gauge to the high pressure outlet when checking for overload.
    While cooling:
    The following does not apply when the outside air temperature is low or when the fan speed is limited. When both compressor 1 and compressor 2 are operating and fan mode is 14 (maximum fan speed), the high pressure saturation temperature should be approximately 15°C above the outside air temperature. If it is 5°C or more above this level, it is possible that an overload has occurred.
    While heating:
    In an indoor unit, the refrigerant flow is poor (E1 temperature and outlet temperature are low), and the mechanical valve of this unit is on 3

Problem with the low pressure sensor

1. A / D step is 10 steps or less (short circuit).
2. A / D step is 1014 steps or more (open circuit).

1. Sensor malfunction (including connector)
2. PCB fault

1. Measure sensor resistance. Check whether the sensor is functioning normally.
2. Use a remote control or PC monitor to check the temperature detected by the microcomputer.

1. Discharge temp. of 100°C or higher was found 20 minutes or more after the compressor stopped.
2. Discharge temperature of 70°C or higher was found after all the compressors were stopped for 60 minutes or longer.
3. A / D step is 10 steps or less (short circuit).

1. Malfunction of the sensor Malfunction of the sensor element The sensor wiring is partially disconnected, which leads to increased electrical resistance. This alarm does not occur if the wiring is broken or the plug is not connected to the outdoor unit PCB.
2. Wiring crossed or installation error The outlet temperature sensor of this compressor is connected to the outlet pipe of the other compressor. The connector for the outlet temperature sensor of the problematic compressor is connected to the PCB connector of the outdoor unit for the other compressor.
3. PCB error of the outdoor unit
4. The check valve on the outlet pipe of this compressor is wet.
5. A short circuit in the air around the outdoor unit has increased the ambient temperature of the outdoor unit and the cooling effects after the compressor was switched off.
6. There is a cause that leads to a P03, P17 or P02 alarm.
7. Electrical noise

1. Sensor malfunction and outdoor unit circuit board failure
Problem:

    Always shows a high temperature.
    When monitoring software or other means of monitoring are used, the discharge temperature sometimes fluctuates suddenly and erratically.
    In some cases, the exact temperature may not be known even if monitoring software is used.

Test:

    Wiggle the sensor and check if the error persists.
    Check whether the connector is partially disconnected from the circuit board.
    • An F04 alarm is not triggered if the connector is completely removed (circuit is open).
    If the cause is still uncertain, check the following to determine if a sensor or PCB error has occurred.
    Step 1:
    Connect the other compressor discharge sensor, or a discharge sensor that did not have an F04 alarm, to the connector for that compressor on the circuit board. Measure the temperature at the same point (in a place with small temperature fluctuations) and check whether there is a temperature difference.
    Difference → A circuit board or sensor error is possible.
    No difference → Circuit board and sensor are normal.
    Step 2:
    If a malfunction was detected in stage 1, connect the faulty compressor sensor to the other compressor connector on the circuit board or to the circuit board connector of a unit that did not have an F04 alarm. Measure the temperature at the same point (in a place with small temperature fluctuations) and check whether there is a temperature difference.
    Difference → Sensor error.
    No difference → PCB error.
    • It is advisable to have an outlet temperature sensor at hand at this time.

2. Crossed wiring or installation error
Trouble:

Although the other compressor is operating and this compressor is stopped, the outlet temperature of the other compressor does not rise and the outlet temperature of this compressor increases.
• The outlet temperature remains high immediately after the compressor stops. Wait some time after the compressor stops and observe.

Although the other compressor is operating and this compressor is stopped, the outlet temperature of the other compressor does not rise and the outlet temperature of this compressor increases.
• The outlet temperature remains high immediately after the compressor stops. Wait some time after the compressor stops and observe.

Check:

Check for wiring and installation errors.

3. Leakage at the outlet pipe check valve
Trouble:

Although the other compressor is operating and this compressor is stopped, the outlet temperature of this compressor rises along with the temperature of the other compressor.

4. The ambient temperature around the outdoor unit, when it is stopped, is 43°C or more.

5. If after checking the above items the cause is still unknown, it is possible that electrical noise is the cause of the problem. It is necessary to provide a line filter or take other countermeasures against noise.

1.     Replace the sensor.
2.     Replace the outdoor unit circuit board.
3.     Carry out noise protection measures.
4.     Repair refrigerant hose.
5.     Adjust the amount of refrigerant.
6.     Rectify the error.

1. A / D step is 10 steps or less (short circuit).
2. A / D step is 1014 steps or more (open circuit).

1. Sensor malfunction (including connector)
2. PCB fault

1. Measure sensor resistance. Check whether the sensor is functioning normally.
2. Use a remote control or PC monitor to check the temperature detected by the microcomputer.

1. A / D step is 10 steps or less (short circuit).
2. A / D step is 1014 steps or more (open circuit).

1. Sensor malfunction (including connector)
2. PCB fault

1. Measure sensor resistance. Check whether the sensor is functioning normally.
2. Use a remote control or PC monitor to check the temperature detected by the microcomputer.

1. Solid-state memory is not available during the power initialisation.
2. The read values do not match after writing into the solid-state memory.

1. The memory was not inserted after the board was replaced.
2. The lifespan of the solid-state memory has been reached.
3. The solid-state memory is incorrectly installed (incorrect direction, bent pins, etc.).

1. Current transformer circuit failure (including cable break etc.)
2. Connector of the transformer circuit removed
3. Missing phase to which the transformer circuit is connected.
4. This current transformer circuit is connected to the connection of the other current transformer circuit.
5. PCB error
6. Electrical noise

1. CT circuit failure, PCB failure

Problem: The current value during compressor operation is below the threshold.

Check:
• Make sure that the plug is not removed
• Check the continuity of the transformer circuit.
• Install a normal transformer instead of this transformer and check it. If current is detected, the circuit board can be judged to be OK.
→ Transformer is faulty
• Check whether current flows in the phase to which the current transformer circuit is connected. Test voltage and current.

2. Crossed wiring or installation error

Problem: If the compressor is stopped, the actual value on the other compressor is high.
☆ If this type of condition occurs, the recording of the occupancy has priority.

3. If after checking the above items the cause is still unknown, it is possible that the noise is the cause of the problem. It is necessary to connect a PC or other instrument

1. Replace the transformer circuit.
2. Replace the outdoor unit board.
3. Rectify the problem.

1. The connector was not inserted after the board has been replaced.

• This alarm occurs if the temperature sensor of the discharge sensor is not inserted in the sensor holder of the tube or if the sensor itself is malfunctioning as a cut wire.
• At an outside air temperature of 10°C or higher: An alarm is triggered if the temperature detected by the outlet sensor has changed by less than 2°C, if the compressor has been in operation for 10 minutes immediately after starting.
• If the outside air temperature is below 10°C: An alarm is triggered if the temperature detected by the outlet sensor has changed by less than 2°C, if the compressor has been in operation for 30 minutes immediately after starting.

1. The detector for the temperature of the discharge sensor is not inserted into the sensor holder of the tube.
2. The discharge sensor itself has a malfunction other than a cut wire.

2. Make sure that sufficient heat-conductive putty is applied.
3. Remove the discharge sensor from the sensor holder and expose the sensor to outside air for about 5 minutes. Make sure that the temperature detected by the sensor adapts to the outside air temperature. (However, the sensor cannot detect temperatures at or below 0°C.)

1.  Place the sensor in the holder and apply sufficient heat-conductive putty.
2.  If the sensor is defective, replace it.

The outlet temperature sensor is generally a sensor designed to accurately detect high temperatures. Therefore, the temperature is not accurately measured when the temperature at the measuring point is 20°C or less.

During A / C operation, a message is issued when the low pressure sensor installed on parts with constant low pressure continuously detects a pressure of 0.05 MPa or less or an instantaneous pressure of 0.02 MPa or less for 2 minutes. (These values represent an unusually low pressure that can damage the compressor.)
However, the alarm does not occur in the first two cases where the procedure described above is carried out. At these times, the outdoor unit is stopped and the conditions are monitored. The alarm occurs when the above operation is performed for the fifth time. The first four times before the alarm occurs are called "pre-shutdown". If the low pressure sensor detects a pressure of 0.15 MPa or more for 3 minutes of continuous operation after the pre-shutdown occurs, the pre-shutdown counter is reset to 0.
If the low pressure sensor continuously detects a pressure of 0.16 MPa or less for 30 minutes when the compressor is stopped, an alarm is triggered immediately (no pre-shutdown).

The vacuum in the air conditioning system has dropped to a level that no longer occurs under normal conditions.

1. The absolute amount of gas in the system is too low (due to insufficient refrigerant charge or leakage).
2. The refrigerant has accumulated in the circuit and has not returned to the compressor. The refrigerant has accumulated in a one-way flow location and cannot escape. The high pressure level is low, which leads to poor refrigerant flow in the circuit. (A lower high pressure leads to a smaller difference between low pressure and high pressure, which may not be sufficient to cause the refrigerant flow.)
3. The refrigerant circuit is closed and the refrigerant has not returned to the compressor. In some cases, moisture that enters the refrigerant circuit can freeze at places with low pressure and the resulting ice can block the circuit.

☆ When the alarm occurs when there is sufficient refrigerant in the system ((1) and (3)), the liquid refrigerant has definitely accumulated somewhere in the system. Liquid refrigerant generally accumulates in high pressure locations. In this case, the high pressure gradually increases (but cannot increase if the location where the liquid accumulates is sufficiently large). Depending on the refrigerant saturation temperature, it can also accumulate in places with low pressure. In this case, it is unlikely that the high pressure will increase.

1. Check whether the service valve is open.
2. Make sure that none of the valves (solenoid valves, mechanical valves) in the main refrigerant circuit are closed due to a malfunction.
3. Make sure that no foreign matter or water has entered the refrigerant circuit.
4. Make sure that the valve leakage on a stopped secondary unit does not result in the accumulation of refrigerant in this secondary unit
5. Make sure that no refrigerant leaks.

1. If a valve fault has occurred, the valve generally needs to be replaced.
2. If a foreign body or moisture has got into the circuit, install a strainer or a dry core (depending on the degree of the problem).
3. If refrigerant enters the stopped secondary unit, it is likely that a valve leak has occurred. The valve must be replaced.

This alarm occurs when a plug connection (pins 1 and 2 for compressor 1) is open.

1. Connect the plug.
2. Correct the connection at pins 1 and 2.

Overcurrent alarm for compressor 2 with constant rpm

During operation, the compressor current exceeded 12 A for at least 30 seconds. However, if this alarm goes off 4 seconds after the compressor starts it will not be recognised

During operation, the compressor current has exceeded 14 A for at least 4 seconds. However, this alarm is not recognised 2 seconds after the compressor has started

1. Compressor failure (blocked or partially blocked)
2. Transformer fault (including cable break)
3. Missing power phase
4. Low voltage
5. PCB- Error

1. Compressor failure (partially locked)

Problem: The current value during operation considerably exceeds the value specified above.

Test: If the current for each phase is measured with a clamp meter or similar instrument, check that the current value for all phases is not high. If MG has been switched on (caution), make sure that no compressor noises occur or that the compressor does not run with a groaning noise.

2. CT circuit failure, PCB failure

Check:
• Check for bad plug contact.
• Check the continuity of the transformer circuit.
• Install a normal transformer instead of this transformer and check it. If current is detected, the board can be fixed.
→ Transformer is faulty
• Check whether current flows in the phase to which the current transformer circuit is connected.
→ Test voltage and current.

3. Missing power phase

problem: This alarm mainly occurs when the T phase is missing. If the R phase or S phase is missing, transformer or PCB continuity problems arise. However, this may not apply in the event of a missing phase caused by a magnetic SW error.

Check: There is a possibility of a magnetic SW error. Therefore, check the phase voltage in a location as close as possible to the compressor.

4. Low voltage

problem: In most cases, this occurs when another constant speed compressor (including compressors in other units) or another unit is started. This also occurs when the power cables are extremely long.

Test: Check the voltage between the individual phases. However, if this occurs when starting other units or compressors, an oscilloscope is required.

5. PCB error

Test: Ensure that the current value measured with the clamp meter is not below the value measured with the PC or the remote control

6. If after checking the above items the cause is still unknown, it is possible that noise is the cause of the problem. It is necessary to connect a PC or other instrument

Replace the compressor.
Replace the transformer circuit.
Repair electrical circuit.
Adjust the primary-side power. Repair the power cable.
Replace the outdoor unit circuit board.
Rectify the error.
* In the event of a compressor failure, measures are likely to be taken to remedy the cause of the compressor failure (e.g., fluid jam) to prevent recurrence. Make sure that there is no cause for the compressor blocking.

During operation, the compressor current exceeded 12 A for at least 30 seconds. However, this alarm is not recognised 4 seconds after the compressor has started

1. Compressor failure (blocked or partially blocked)
2. Transformer fault (including cable break)
3. Missing power phase
4. Low voltage
5. PCB- Error

1. Compressor failure (partially locked)

Problem: The current value during operation considerably exceeds the value specified above.

Test: If the current for each phase is measured with a clamp meter or similar instrument, check that the current value for all phases is not high. If MG has been switched on (caution), make sure that no compressor noises occur or that the compressor does not run with a groaning noise.

2. CT circuit failure, PCB failure

Check:
• Check for bad plug contact.
• Check the continuity of the transformer circuit.
• Install a normal transformer instead of this transformer and check it. If current is detected, the board can be fixed.
→ Transformer is faulty
• Check whether current flows in the phase to which the current transformer circuit is connected.
→ Test voltage and current.

3. Missing power phase

problem: This alarm mainly occurs when the T phase is missing. If the R phase or S phase is missing, transformer or PCB continuity problems arise. However, this may not apply in the event of a missing phase caused by a magnetic SW error.

Check: There is a possibility of a magnetic SW error. Therefore, check the phase voltage in a location as close as possible to the compressor.

4. Low voltage

problem: In most cases, this occurs when another constant speed compressor (including compressors in other units) or another unit is started. This also occurs when the power cables are extremely long.

Test: Check the voltage between the individual phases. However, if this occurs when starting other units or compressors, an oscilloscope is required.

5. PCB error

Test: Ensure that the current value measured with the clamp meter is not below the value measured with the PC or the remote control.

6. If after checking the above items the cause is still unknown, it is possible that noise is the cause of the problem. It is necessary to connect a PC or other instrument

Replace the compressor.
Replace the transformer circuit.
Repair electrical circuit.
Adjust the primary-side power. Repair the power cable.
Replace the outdoor unit circuit board.
Rectify the error.
* In the event of a compressor failure, measures are likely to be taken to remedy the cause of the compressor failure (e.g., fluid jam) to prevent recurrence. Make sure that there is no cause for the compressor blocking.

1. Transformer circuit failure (including cable break etc.)
2. Current transformer circuit connector disconnected
3. Missing phase to which the current transformer circuit is connected
4. This transformer circuit is connected to the connection of the other current transformer circuit.
5. PCB error
6. Electric noise

1. CT circuit failure, PCB failure

Problem: The current value during compressor operation is below the threshold.

Check:
• Make sure that the plug is not removed
• Check the continuity of the transformer circuit.
• Install a normal transformer instead of this transformer and check it. If current is detected, the circuit board can be judged to be OK.
→ Transformer is faulty
• Check whether current flows in the phase to which the current transformer circuit is connected. Test voltage and current.

2. Crossed wiring or installation error

Problem: If the compressor is stopped, the actual value on the other compressor is high.
☆ If this type of condition occurs, the recording of the occupancy has priority.

3. If after checking the above items the cause is still unknown, it is possible that the noise is the cause of the problem. It is necessary to connect a PC or other instrument

1. Replace the transformer circuit.
2. Replace the outdoor unit board.
3. Rectify the problem.

1. The connector was not inserted after the board has been replaced.

• This alarm occurs if the temperature sensor of the discharge sensor is not inserted in the sensor holder of the tube or if the sensor itself is malfunctioning as a cut wire.
• At an outside air temperature of 10°C or higher: An alarm is triggered if the temperature detected by the outlet sensor has changed by less than 2°C, if the compressor has been in operation for 10 minutes immediately after starting.
• If the outside air temperature is below 10°C: An alarm is triggered if the temperature detected by the outlet sensor has changed by less than 2°C, if the compressor has been in operation for 30 minutes immediately after starting.

1. The detector for the temperature of the discharge sensor is not inserted into the sensor holder of the tube.
2. The discharge sensor itself has a malfunction other than a cut wire.

2. Make sure that sufficient heat-conductive putty is applied.
3. Remove the discharge sensor from the sensor holder and expose the sensor to outside air for about 5 minutes. Make sure that the temperature detected by the sensor adapts to the outside air temperature. (However, the sensor cannot detect temperatures at or below 0°C.)

1.  Place the sensor in the holder and apply sufficient heat-conductive putty.
2.  If the sensor is defective, replace it.

The outlet temperature sensor is generally a sensor designed to accurately detect high temperatures. Therefore, the temperature is not accurately measured when the temperature at the measuring point is 20°C or less.

Overcurrent alarm for compressor 3 with constant rpm

During operation, the compressor current exceeded 12 A for at least 30 seconds. However, if this alarm goes off 4 seconds after the compressor starts it will not be recognised

During operation, the compressor current has exceeded 14 A for at least 4 seconds. However, this alarm is not recognised 2 seconds after the compressor has started

1. Compressor failure (blocked or partially blocked)
2. Transformer fault (including cable break)
3. Missing power phase
4. Low voltage
5. PCB- Error

1. Compressor failure (partially locked)

Problem: The current value during operation considerably exceeds the value specified above.

Test: If the current for each phase is measured with a clamp meter or similar instrument, check that the current value for all phases is not high. If MG has been switched on (caution), make sure that no compressor noises occur or that the compressor does not run with a groaning noise.

2. CT circuit failure, PCB failure

Check:
• Check for bad plug contact.
• Check the continuity of the transformer circuit.
• Install a normal transformer instead of this transformer and check it. If current is detected, the board can be fixed.
→ Transformer is faulty
• Check whether current flows in the phase to which the current transformer circuit is connected.
→ Test voltage and current.

3. Missing power phase

problem: This alarm mainly occurs when the T phase is missing. If the R phase or S phase is missing, transformer or PCB continuity problems arise. However, this may not apply in the event of a missing phase caused by a magnetic SW error.

Check: There is a possibility of a magnetic SW error. Therefore, check the phase voltage in a location as close as possible to the compressor.

4. Low voltage

problem: In most cases, this occurs when another constant speed compressor (including compressors in other units) or another unit is started. This also occurs when the power cables are extremely long.

Test: Check the voltage between the individual phases. However, if this occurs when starting other units or compressors, an oscilloscope is required.

5. PCB error

Test: Ensure that the current value measured with the clamp meter is not below the value measured with the PC or the remote control

6. If after checking the above items the cause is still unknown, it is possible that noise is the cause of the problem. It is necessary to connect a PC or other instrument

Replace the compressor.
Replace the transformer circuit.
Repair electrical circuit.
Adjust the primary-side power. Repair the power cable.
Replace the outdoor unit circuit board.
Rectify the error.
* In the event of a compressor failure, measures are likely to be taken to remedy the cause of the compressor failure (e.g., fluid jam) to prevent recurrence. Make sure that there is no cause for the compressor blocking.

During operation, the compressor current has exceeded 14 A for at least 4 seconds. However, this alarm is not recognised 2 seconds after the compressor has started

1. Compressor failure (blocked or partially blocked)
2. Transformer fault (including cable break)
3. Missing power phase
4. Low voltage
5. PCB- Error

1. Compressor failure (partially locked)

Problem: The current value during operation considerably exceeds the value specified above.

Test: If the current for each phase is measured with a clamp meter or similar instrument, check that the current value for all phases is not high. If MG has been switched on (caution), make sure that no compressor noises occur or that the compressor does not run with a groaning noise.

2. CT circuit failure, PCB failure

Check:
• Check for bad plug contact.
• Check the continuity of the transformer circuit.
• Install a normal transformer instead of this transformer and check it. If current is detected, the board can be fixed.
→ Transformer is faulty
• Check whether current flows in the phase to which the current transformer circuit is connected.
→ Test voltage and current.

3. Missing power phase

problem: This alarm mainly occurs when the T phase is missing. If the R phase or S phase is missing, transformer or PCB continuity problems arise. However, this may not apply in the event of a missing phase caused by a magnetic SW error.

Check: There is a possibility of a magnetic SW error. Therefore, check the phase voltage in a location as close as possible to the compressor.

4. Low voltage

problem: In most cases, this occurs when another constant speed compressor (including compressors in other units) or another unit is started. This also occurs when the power cables are extremely long.

Test: Check the voltage between the individual phases. However, if this occurs when starting other units or compressors, an oscilloscope is required.

5. PCB error

Test: Ensure that the current value measured with the clamp meter is not below the value measured with the PC or the remote control.

6. If after checking the above items the cause is still unknown, it is possible that noise is the cause of the problem. It is necessary to connect a PC or other instrument

Replace the compressor.
Replace the transformer circuit.
Repair electrical circuit.
Adjust the primary-side power. Repair the power cable.
Replace the outdoor unit circuit board.
Rectify the error.
* In the event of a compressor failure, measures are likely to be taken to remedy the cause of the compressor failure (e.g., fluid jam) to prevent recurrence. Make sure that there is no cause for the compressor blocking.

1. Transformer circuit failure (including cable break etc.)
2. Current transformer circuit connector disconnected
3. Missing phase to which the current transformer circuit is connected
4. This transformer circuit is connected to the connection of the other current transformer circuit.
5. PCB error
6. Electric noise

1. CT circuit failure, PCB failure

Problem: The current value during compressor operation is below the threshold.

Check:
• Make sure that the plug is not removed
• Check the continuity of the transformer circuit.
• Install a normal transformer instead of this transformer and check it. If current is detected, the circuit board can be judged to be OK.
→ Transformer is faulty
• Check whether current flows in the phase to which the current transformer circuit is connected. Test voltage and current.

2. Crossed wiring or installation error

Problem: If the compressor is stopped, the actual value on the other compressor is high.
☆ If this type of condition occurs, the recording of the occupancy has priority.

3. If after checking the above items the cause is still unknown, it is possible that the noise is the cause of the problem. It is necessary to connect a PC or other instrument

1. Replace the transformer circuit.
2. Replace the outdoor unit board.
3. Rectify the problem.

1. The connector was not inserted after the board has been replaced.

• This alarm occurs if the temperature sensor of the discharge sensor is not inserted in the sensor holder of the tube or if the sensor itself is malfunctioning as a cut wire.
• At an outside air temperature of 10°C or higher: An alarm is triggered if the temperature detected by the outlet sensor has changed by less than 2°C, if the compressor has been in operation for 10 minutes immediately after starting.
• If the outside air temperature is below 10°C: An alarm is triggered if the temperature detected by the outlet sensor has changed by less than 2°C, if the compressor has been in operation for 30 minutes immediately after starting.

1. The detector for the temperature of the discharge sensor is not inserted into the sensor holder of the tube.
2. The discharge sensor itself has a malfunction other than a cut wire.

2. Make sure that sufficient heat-conductive putty is applied.
3. Remove the discharge sensor from the sensor holder and expose the sensor to outside air for about 5 minutes. Make sure that the temperature detected by the sensor adapts to the outside air temperature. (However, the sensor cannot detect temperatures at or below 0°C.)

1.  Place the sensor in the holder and apply sufficient heat-conductive putty.
2.  If the sensor is defective, replace it.

The outlet temperature sensor is generally a sensor designed to accurately detect high temperatures. Therefore, the temperature is not accurately measured when the temperature at the measuring point is 20°C or less.

This alarm occurs when a plug connection (pins 4 and 5 for compressor 2) is open.

1. Connect the plug.
2. Correct the connection at pins 4 and 5.

This alarm occurs when a plug connection (pins 7 and 8 for compressor 3) is open.

1. Connect the plug.
2. Correct the connection at pins 7 and 8.

Check the power and connection cables. If the wiring and connections are normal, use a tester to measure the resistance between the HIC performance of the compressor (HIC +) and ground (HIC–).
In the event of a short circuit, there is a HIC fault.

Check the settings of the system address again

1. Connect the connector.
2. Correct the connection on pins 4 and 5.

1. A unit with R407C refrigerant or a model R22 unit was accidentally connected.
2. The connected unit is correct, but the refrigerant type setting in the outdoor unit's EEPROM (item code 80) is incorrect.

1. Check the refrigerant type on the connected device.
2. Use the remote control to service the outdoor unit and check the refrigerant type with item number 80. If the setting is incorrect, change it in R410A.

1. A unit with R407C refrigerant or a model R22 unit was accidentally connected. The 4-way valve connector (20S CN022) has been disconnected from the control board.
2. The 4-way valve circuit is blocked (fault).

1. Check the 4-way valve connector (20S CN022).
2. If the connector is OK, check the 4-way valve wiring and PCB circuit.

• Switch off the compressor at constant speed for 60 minutes and cool the thermostat.
• Replace defective parts with new ones.

1. Blockage of the liquid valve capillaries
2. Insufficient amount of refrigerant (including problems due to insufficient initial charge and gas leakage)
3. Blocking of low-pressure parts through the penetration of foreign bodies (moisture, scale, etc.)
4. Crossing (hose or circuit board connector) with the other compressor thermistor
5. Malfunction of the expansion valve
6. Accumulation of refrigerant on stopped outdoor units
7. Sensor for compressor discharge defective
8. PCB- Error (A / D conversion error)
9. Electrical noise

1. Capillary blockage

problem: The compressor outlet temperature does not drop even if the liquid valve is switched on.

If the fluid valve is in operation and the liquid valve is switched on, check whether the secondary side of the liquid capillaries is cold.

2. Too little refrigerant

problem: The fluid effect is bad

Test: Check whether or not the superheat temperature drops when the mechanical valve of the evaporator is opened to 300 pulses or more (after checking for foreign matter).

3. Contamination by foreign bodies

Problem: The effectiveness of the fluid valve is poor

Control: Make sure that there is no difference in condensation or frost conditions between the primary and secondary tubes of the strainer.

4. Crossed thermistor

problem: The outlet temperature of the other compressor is high, although only this compressor is in operation. When the liquid valve turns on, the outlet temperature of the other compressor drops.

5. Accumulation of refrigerant in stopped outdoor units

Problem:
• The system is OK when all outdoor units are in operation. However, when a certain outdoor unit is stopped, symptoms of insufficient gas appear.
• Condensation or frost are visible up to the top of the battery of the stopped outdoor unit.
• After stopping an outdoor unit, there is a sound when refrigerant flows into an outdoor unit that has been stopped for a long time.
• If an outdoor unit starts after a long rest, the start is accompanied by strong vibrations.

The operation of the electronic circuit in the high pressure switch can short-circuit the connection depending on the pressure. The terminal is short-circuited at a pressure of 3.3 MPa or more. As soon as the connection is short-circuited, it remains in this state until the pressure drops below 2.6 MPa.

1. Failure of the check valve in the pressure pipe of the compressor.
2. The service valve is closed.
3. Blockage of the outdoor heat exchanger when cooling down.
4. An air short in the outdoor unit during cooling.
5. Failure of the outdoor fan during cooling.
6. Blockage of the air filter in the indoor unit during heating.
7. Air short in the indoor unit during heating.
8. Failure of the indoor fan when heating.
9. Blockage of the refrigerant circuit.
10. Failure of the mechanical valve.
11. Failure of the solenoid valve set.
12. Refrigerant has been over filled.
13. Failure of the high pressure switch.

1. Make sure that the high pressure switch connector is correctly connected.
2. When the high pressure switch is properly connected, connect a high pressure manometer to the high pressure outlet and monitor the pressure during operation to check the pressure when the high pressure switch is activated. The check valve is likely to fail if the pressure is less than 3.3 MPa. The following describes tests that must be carried out at high pressure.
3. While cooling down, check if the heat exchanger of the outdoor unit is clogged. Remove any material that prevents ventilation.
4. While cooling, check whether there is an air short in the outdoor unit. The system works normally unless the temperature around the outdoor unit is too high.
5. While cooling down, check whether the outdoor fan is defective. Check whether the screws securing the fan are loose and that the fan connector on the outdoor unit PCB is properly connected.
6. While heating, check whether the air filters in the indoor unit are blocked. If it is blocked, clean the filter.
7. While heating, check whether there is an air short in the indoor unit. The system works normally unless the temperature around the outdoor unit is too high.
8. While heating, check whether the indoor fan is defective.
9. Check if the refrigerant circuit is blocked. Check that all service valves are closed. Check whether the welds are blocked.
10. Check whether the mechanical valve is defective. Check if the mechanical valves cause rattling when resetting the power supply. Since the mechanical valve in the indoor unit is in a place that makes it difficult to test by ear, use an electrical device for testing. Check that the mechanical valve connector pin on the board outputs 4V. Also check that the coil resistance of the mechanical valve is several tens Ω.
11. Check whether the solenoid valve set is defective. Removing a coil that is switched on results in a clicking sound. Removing a coil that is not switched on also does not result in such a sound.
12. Check whether the refrigerant has been over charged. Too much refrigerant has been charged when the subcooling temperature of the condenser is 15°C or higher.

1. A fault is evaluated if the outdoor unit receives the O2 alarm signal generated by the indoor unit.
2. If the EEPROM setting of the indoor unit (item code 0B) is set to 0001, the EXCT input short-circuited.

Priority check

1. System configuration
          1-1 Is an O2 sensor being used?
          If yes, see 3-1.
          If no, see 2-1.
        
       2-1 Internal EEPROM setting
          Is the EEPROM setting, item code 0B, on the internal control card set to 0001?
          If yes, see 3-1 after changing.
          If no, see 4-1.
        
       3-1 EXCT wiring
          Is the EXCT socket (cable) short-circuited?
          If yes, change the wiring.
          If no, see 4-1.
                                                         
       Internal control card
          4-1 Is the alarm triggered when the EXCT connector (cable) is disconnected and the power supply is reset?
          If yes, see 4-3.
          If not, see 4-2.

   4-2 See what happens because there is no error.

          4-3 Internal control card defective → replace card

This alarm occurs when a current fault or a current detection fault occurs (when a fault judgment current is detected in the primary or secondary current or if an instantaneous secondary current of 18 A * or higher is detected).
* Changed to output errors due to current regardless of the frequency of the inverter.
  In addition to this there are 6 HP and 10 HP compressors.

    If more than the overcurrent values in the primary and secondary current specified in the table have been determined.

    Primary secondary
      6 HP compressors 18 A 18 A
    10 HP Compressors 21 A 21 A

    If more than the current values specified in the table are immediately detected in the secondary current.

    Second
      6 HP compressors 28 A
    10 HP compressors 36 A

There is a strong possibility of a compressor failure. An alarm for current detection problems occurs when it is determined that no current is flowing after the start (DCCT is damaged). In this case, the cause is a DCCT error.

1. Blockage of the liquid valve capillaries
2. Insufficient amount of refrigerant (including problems due to insufficient initial charge and gas leakage)
3. Blocking of low-pressure parts through the penetration of foreign bodies (moisture, scale, etc.)
4. Crossing (hose or circuit board connector) with the other compressor thermistor
5. Malfunction of the expansion valve
6. Accumulation of refrigerant on stopped outdoor units
7. Sensor for compressor discharge defective
8. PCB- Error (A / D conversion error)
9. Electrical noise

1. Capillary blockage

problem: The compressor outlet temperature does not drop even if the liquid valve is switched on.

If the fluid valve is in operation and the liquid valve is switched on, check whether the secondary side of the liquid capillaries is cold.

2. Too little refrigerant

problem: The fluid effect is bad

Test: Check whether or not the superheat temperature drops when the mechanical valve of the evaporator is opened to 300 pulses or more (after checking for foreign matter).

3. Contamination by foreign bodies

Problem: The effectiveness of the fluid valve is poor

Control: Make sure that there is no difference in condensation or frost conditions between the primary and secondary tubes of the strainer.

4. Crossed thermistor

problem: The outlet temperature of the other compressor is high, although only this compressor is in operation. When the liquid valve turns on, the outlet temperature of the other compressor drops.

5. Accumulation of refrigerant in stopped outdoor units

Problem:
• The system is OK when all outdoor units are in operation. However, when a certain outdoor unit is stopped, symptoms of insufficient gas appear.
• Condensation or frost are visible up to the top of the battery of the stopped outdoor unit.
• After stopping an outdoor unit, there is a sound when refrigerant flows into an outdoor unit that has been stopped for a long time.
• If an outdoor unit starts after a long rest, the start is accompanied by strong vibrations.

1. Blockage of the liquid valve capillaries
2. Insufficient amount of refrigerant (including problems due to insufficient initial charge and gas leakage)
3. Blocking of low-pressure parts through the penetration of foreign bodies (moisture, scale, etc.)
4. Crossing (hose or circuit board connector) with the other compressor thermistor
5. Malfunction of the expansion valve
6. Accumulation of refrigerant on stopped outdoor units
7. Sensor for compressor discharge defective
8. PCB- Error (A / D conversion error)
9. Electrical noise

1. Capillary blockage

problem: The compressor outlet temperature does not drop even if the liquid valve is switched on.

If the fluid valve is in operation and the liquid valve is switched on, check whether the secondary side of the liquid capillaries is cold.

2. Too little refrigerant

problem: The fluid effect is bad

Test: Check whether or not the superheat temperature drops when the mechanical valve of the evaporator is opened to 300 pulses or more (after checking for foreign matter).

3. Contamination by foreign bodies

Problem: The effectiveness of the fluid valve is poor

Control: Make sure that there is no difference in condensation or frost conditions between the primary and secondary tubes of the strainer.

4. Crossed thermistor

problem: The outlet temperature of the other compressor is high, although only this compressor is in operation. When the liquid valve turns on, the outlet temperature of the other compressor drops.

5. Accumulation of refrigerant in stopped outdoor units

Problem:
• The system is OK when all outdoor units are in operation. However, when a certain outdoor unit is stopped, symptoms of insufficient gas appear.
• Condensation or frost are visible up to the top of the battery of the stopped outdoor unit.
• After stopping an outdoor unit, there is a sound when refrigerant flows into an outdoor unit that has been stopped for a long time.
• If an outdoor unit starts after a long rest, the start is accompanied by strong vibrations.

1. Forgot to open the valve
2. Malfunction of the mechanical valve
3. Idle speed away from the outside fan

Check fan motor wiring, Hall IC wiring, and connector connections.
If the wiring and connections are OK, check that the Hall IC input circuit capacitor is firmly soldered to the control board of the outdoor unit. Also use a tester and measure the resistance between fan HIC power (HIC +) and ground (HIC–).
In the event of a short circuit, there is a HIC fault.

If the fan does not start, the following corrections can be effective.

•     If there is a fan HIC error or a circuit error, replace the board.
•     If the fan motor is blocked, replace the fan motor.