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Troubleshooting steps:

1 This fault occurs during the EEV pressure equalization phase. When this alarm appears, the EEV cannot complete initialization, and the unit cannot enter cooling or dehumidification mode.

2. When this alarm occurs, first check the suction pressure and discharge pressure values in the sensor status. Based on the refrigerant type and current temperature, consult the corresponding saturation pressure-temperature chart to verify whether the pressures are too high or too low.

3. Check whether all valves in the unit are fully opened, including solenoid valves, check valves, ball valves, and indoor/outdoor unit service valves. Remove the pressure sensors and inspect them for oil blockage; clean them if necessary.

4. Connect a pressure gauge and compare its readings with the values displayed on the controller. If there is a significant deviation, it is likely that the pressure sensor is faulty. If other alarms are present at the same time, contact the manufacturer for further assistance.

Troubleshooting steps:

1. In the status menu, go to Equipment Status – Humidifier Runtime and check the actual humidifier runtime.

2. If the actual runtime exceeds 2000 hours (default value), the humidifier requires cleaning and maintenance. After maintenance is completed, log in with the service password 504600, locate the time reset option, and clear the humidifier runtime. Then, confirm in the status menu that the humidifier runtime has been reset to zero, and manually clear the alarm.

3. If the actual runtime is less than 2000 hours (default value), the cause may be a protocol error, outdated software version, or an alarm threshold set too low. In this case, provide the software version number and serial number (SN) and contact the manufacturer for assistance.

FAQ For INV IGBT Driver Block-Set Alarm
Applicable Equipment Model：RMX 40/50X

Q: The equipment suddenly reports an "INV IGBT Driver Block-Set" fault. What is the cause?
A: The main cause is abnormal inverter voltage or abnormal voltage detection.

Q: How should we troubleshoot and resolve this fault?
A: Please follow the inspection steps below:
1. Check the inverter power board
* Inspect the inverter power board of the power module for obvious burn marks.
* Check whether key components (such as inverter driver / inverter IGBT) are damaged.
Recommendation: If a spare inverter power board is available, power off the equipment first, replace the board, then restart the unit to check if the alarm is cleared.
2. Check the inverter busbar board
* Inspect the inverter busbar board for obvious damage.
* Check whether the fuse on the inverter busbar board is blown.
Recommendation: If a spare inverter busbar board is available, power off the equipment first, replace the board, then restart the unit to check if the alarm is cleared.

This is the test mode for the keyboard control board. Pressing “PRG” and “ENT” simultaneously activates it. It is a method we use during debugging to verify whether the control board is functioning properly. Simply power cycle the device to exit test mode.

1. manual bypass, set P13.11 manually to bypass the corresponding unit group 
2. automatic bypass, when the VFD unit fails, the VFD automatically bypasses the corresponding unit group 
3. neutral point bypass, when a unit fails, the VFD automatically fails the unit 
Caution, 
1. bypass up to 2 groups of units 
2. when the unit communication fails, the unit can not receive bypass commands and can not be bypassed 
3. after neutral point bypass, you need to set P13.10 = 0, and then set P13.11 to reset the unit bypass status. Cannot be bypassed 3. After neutral point bypass, you need to set P13.10=0 and then set P13.11 to reset the unit bypass status.

Q: When the GD200A inverter is connected to a motor, the operating frequency does not rise above 19 Hz and a low-voltage fault is reported. However, it operates normally without a motor connected. What are the possible causes?
A: Causes:
1. The input voltage—especially during startup and when reaching 19 Hz—is below 340 V (for a three-phase 380 V inverter). This could be due to worn-out contactor contacts or poor contact in the upstream circuit breaker/fuse;
2. The internal electrolytic capacitors in the inverter may degrade over time or in high-temperature environments, resulting in reduced energy storage capacity;
3. There may be insulation issues with the motor or cables.
Troubleshooting Steps:
1. First, use a multimeter to measure the input voltage and check if it drops significantly when the motor reaches 19 Hz. If so, address the external wiring.
2. If the input voltage remains stable, the issue is most likely due to aging capacitors inside the inverter or a problem with the rectifier circuit’s contactor. Replace the contactor or capacitors.

Here are the troubleshooting steps:

1. Check if the maintenance circuit breaker is actually closed.

2. Connect the MTR and check the dry contact settings. Is there a setting for the maintenance circuit breaker to be closed? Change it to another option. If the alarm disappears, the dry contact board is damaged.

3. Check the J3 cable on the monitoring interface board. Disconnect it. If the alarm disappears, the auxiliary contact of the maintenance circuit breaker or the corresponding signal cable is damaged. If the alarm persists, the monitoring interface board or control board is damaged.

Q:In INVT EC160A VFD, the cooling fan runs continuously after power ON. The drive is functioning normally, but the customer considers this abnormal since the fan should run only after the RUN command. What could be the issue?
A: In this condition, check the driver board—specifically the Q3 transistor. A faulty Q3 transistor can cause the cooling fan to run continuously even without a RUN command.
After replacing the defective component, the drive operates normally and the fan behavior returns to standard logic.
Normal Condition: NDZ4
Faulty Condition: 6003XY1XN04

For IVC1S/IVC1L series PLCs

The power-off data of this series of PLCs is stored in permanent storage media, eliminating the need for a backup battery, and the storage scope is set in the system block (supports M and D components). 

When "data cannot be saved due to power failure, Memory error fault" occurs 

Steps to resolve the issue:
1. Check the "Power-off Save Range" setting in the system block to confirm that the M and D components to be saved have been included in the set range without omission;
2. Re-download the program and system blocks, write test data, power off and let it stand for 3 - 5 minutes, then restart, and check if the Memory error still appears;
3. If the error persists and data cannot be saved, it indicates that the permanent storage chip inside the PLC is damaged (not a setting issue), and the PLC unit needs to be replaced; it cannot be repaired by adjusting the program.

For IVC2/IVC3/IVC5 series PLCs

PLCs in this series rely on backup batteries to save data during power outages, and battery malfunctions can directly lead to data loss and error reporting. 

Steps to resolve the issue:
1. Prioritize checking the status of backup batteries and promptly replace failed batteries (to avoid data loss and error reporting caused by battery issues);
2. Confirm that the setting of "Power-off Save Range" in the system block is correct (the two sets of settings have no conflicts and are in a union relationship), to avoid data loss caused by incorrect range settings;
3. Re-download the program and system blocks, write test data, and perform a power-off test on the save function;
4. If an error still occurs after replacing the battery and resetting, it indicates a hardware failure in the internal storage, and professional personnel should be contacted for repair or PLC replacement.