Growatt | Grid-Tied Inverter Error Guide

Why does the inverter report high DC voltage (Error 202)?

Analysis: The source guidance states that the maximum DC input is typically up to 550 V for the referenced single-phase Growatt models and up to 1,100 V for the referenced three-phase models. If the string voltage exceeds the inverter's permitted maximum, the inverter reports excessive PV input voltage.

Solution: Check every string and make sure the total open-circuit voltage remains below the inverter's maximum permitted input voltage. The effect of ambient temperature on module voltage must also be taken into account.

Why does the inverter report “PV insulation resistance too low” (Error 203)?

Analysis: Grid-tied inverters check insulation resistance between the PV array and earth before operation. A fault or leakage path between a string conductor and earth can trigger this error and must be investigated. The source guidance cites an insulation resistance below approximately 50 kΩ as an indication of a possible leakage fault for the affected units.

Solution: Locate and correct the affected string or wiring fault. If the PV wiring and insulation are confirmed to be correct but the error remains, the inverter may require replacement or service.

Why does the inverter report “AC voltage out of range” (Error 300)?

Analysis: Grid-tied inverters operate within the voltage limits required by the configured grid code. Grid fluctuations can cause the measured voltage to move outside this range and the inverter will then disconnect from the grid. The original guidance gives the example of a 195–253 V range under a specific Chinese CQC configuration.

Solution: Check the actual grid voltage and the selected grid-code settings. Where permitted by the applicable grid requirements, qualified personnel can adjust protection parameters through the inverter settings or supported Growatt tools such as ShineBus, ShinePhone, ShineTools or ShineServer.

Why can a newly installed inverter report abnormal earth-voltage detection?

Analysis: The source guidance identifies an AC voltage difference greater than approximately 20 V between neutral and protective earth during the inverter self-test as a possible cause. Incorrect neutral wiring or an inadequate earth connection can be responsible.

Solution: Check neutral and protective-earth wiring and correct any installation fault. Any change to protective functions or grid settings should only be made where technically and legally permitted.

Why does the inverter report “AC frequency out of range” (Error 304)?

Analysis: The inverter continuously tracks grid frequency. A sudden grid-frequency deviation outside the permitted range causes the inverter to disconnect.

Solution: Check the grid frequency and selected grid code. Where allowed, qualified personnel can adjust the permitted frequency range using the inverter settings or supported Growatt configuration tools.

Why does the inverter report “DC component at output too high” (Error 402)?

Analysis: The inverter output should be an AC waveform. If an abnormal DC component is detected in the output, the inverter reports this fault.

Solution: Service personnel can check the relevant parameters using supported Growatt diagnostic software. If the fault remains, replacement or repair of the inverter may be required.

Why does the inverter report a relay fault (Error 405)?

Analysis: A relay fault can be caused by hardware or by parameters/grid conditions. If it occurs immediately after AC and DC power are applied, the source guidance indicates a hardware problem is more likely. If it appears after the inverter's startup countdown, grid or parameter conditions may be involved.

Solution: An immediate hardware relay fault may require inverter replacement. If the error occurs after the self-test/startup sequence, check grid and configuration conditions and contact service if necessary.

Why does the inverter report “Temperature too high” (Error 408)?

Analysis: Check whether the installation location is sufficiently ventilated and whether the fan is operating normally. If external conditions do not explain the temperature, an internal issue may be present.

Solution: Correct ventilation or cooling problems. If the cause appears internal, review inverter logs and contact service.

Why does the inverter report abnormal bus voltage (Error 409)?

Analysis: This error indicates abnormal internal capacitor/bus voltage or excessive positive/negative deviation. Excessive string voltage or an earthing problem can be possible causes.

Solution: Check string voltage, earthing and wiring. Correct any installation issue and restart the unit. If the wiring is correct and the error persists, contact service.

Why does the inverter report an internal communication fault (Error 411)?

Analysis: On a new unit, transport vibration can potentially loosen an internal control-board connection. On an older unit, a control-board or firmware problem may be involved.

Solution: Qualified service personnel should inspect the internal connections where appropriate. If the fault occurred during normal use, contact service.

Why does the inverter report an SPD fault alarm (Warning 202)?

Analysis: The inverter contains surge-protection devices on its AC/DC sides. A surge or lightning event can cause the SPD to operate and subsequently fail.

Solution: An SPD fault may not immediately stop power generation, but the protection should be restored. Contact qualified service personnel for inspection and replacement as required.

Why does the inverter report a fan fault (Warning 400)?

Analysis: Check whether the rear fan turns freely and operates normally. Mechanical resistance can indicate a seized fan or bearing problem.

Solution: Replace a defective fan. If the fans are functional or have already been replaced and the warning remains, the fan power-supply circuit may need service.