sunMAX - How Do I Troubleshoot Different Microinverter Error Codes?

Overview


In this article the reader will find the causes and solutions for the different Microinverter error codes. Using the Table of Contents, click on the error you are interested in to view the cause and possible solution.

Table of Contents


Error Codes:

Device Offline PV Over Voltage
AC Over Current HV Bus Over Voltage
AC Over Power GFDI Fault
AC Not Connected Hardware Failure
AC Over Frequency / AC Under Frequency Islanding Detected
AC Over Voltage / AC Under Voltage Over Temperature
AC Voltage Out of Range While Reconnecting AC Frequency Out of Range While Reconnecting
PV Under Voltage AC Frequency Discontinuity

Error: Device Offline


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  • Cause: The Solar Gateway(s) weren’t able to detect a Bluetooth signal from this microinverter.
  • Resolution: At night, this is normal, because microinverters run off panel (PV) power. During the day, the Solar Gateway may be located too far from the array, or there might be too many obstructions between the Solar Gateway and this microinverter. Check the antenna on the microinverter to make sure it is tightly screwed on and that it is oriented correctly.

Error: AC Over Current


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  • Cause: The microinverter grid (AC) current exceeded the safe maximum due to a grid or wiring fault.
  • Resolution: Check the AC wiring to ensure there are no shorts, and that the AC breaker(s) are closed (on). Check the AC line parameters and make sure that they are within the nominal range for your region.

Error: AC Over Power


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  • Cause: The PV input power is too high.
  • Resolution: If using a sunMAX module, extreme cold temperatures and high irradiance may trip this error, but it’s unlikely.  If using another module, a lower power may need to be used.

Error: AC Not Connected


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  • Cause: An AC waveform was not detected on the grid (AC) connection.
  • Resolution: Ensure the AC breaker is closed (on), all wires are connected in the End Run Connector, and all AC connectors are tight with both latches fully engaged.

Error: AC Over Frequency / AC Under Frequency


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  • Cause: The frequency of the AC waveform is too high or too low for the regulatory region selected for your site.
  • Resolution: Make sure the correct regulatory region is selected for your site, using the sunMAX Install application for Android. In the Android app, select your site, then tap “Site / Customer Info”. If the correct region is selected, check the AC frequency and contact your utility to ensure the grid is within specifications.

Error: AC Over Voltage / AC Under Voltage


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  • Cause: The voltage of the AC waveform is too high or too low for the regulatory region selected for your site.
  • Resolution: Make sure the correct regulatory region is selected for your site, using the sunMAX Install application for Android. In the Android app, select your site, then tap “Site / Customer Info”. If the correct region is selected, check the AC voltage and contact your utility to ensure the grid is within specifications.

Error: AC Voltage Out of Range While Reconnecting


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Note - If an inverter stops producing because the AC waveform exceeded the frequency or voltage limits, it will reconnect with stricter limits to avoid repeatedly cycling on and off.

  • Cause: The voltage of the AC waveform was too high or too low for the regulatory region selected for your site.
  • Resolution: Make sure the correct regulatory region is selected for your site, using the sunMAX Install application for Android. Select your site, then tap “Site / Customer Info”. Check the AC voltage and contact your utility to ensure the grid is within specifications.

Error: PV Under Voltage


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  • Cause: The DC voltage from the panel is too low for the inverter to operate.
  • Resolution: If this fault occurs at sunset, it is normal behavior. If the fault occurs during the day, however, the panel may need to be replaced.

Error: PV Over Voltage


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  • Cause: The DC voltage from the panel is too high for the inverter to operate.
  • Resolution: If using a sunMAX module, extreme cold temperatures and high irradiance may trip this error, but it’s unlikely.  If using another module, a lower power may need to be used.

Error: HV Bus Over Voltage


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Note - The HV, or High Voltage, bus may go over voltage if the microinverter grid (AC) is disconnected while the inverter is running.

  • Cause: The voltage on the inverter’s output circuit exceeded the safe maximum, and the inverter stopped automatically.
  • Resolution: The microinverter will resume normal production when the grid (AC) waveform returns.

Error: GFDI Fault


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Note - The Ground Fault Detector Interrupter (GFDI) is a safety mechanism which automatically shuts down the inverter if it detects that the panel’s DC (+) is shorted to ground.

  • Cause: A PV ground fault was detected and the inverter stopped automatically.
  • Resolution: Check the PV cables between the microinverter and the panel, and replace them if necessary.

Error: Hardware Failure


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  • Cause: A component in the inverter is not operating correctly.
  • Resolution: Contact Ubiquiti Support (via live chat in sunMAX software)

Error: Islanding Detected


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Note - Islanding is the situation where there is a grid (AC) outage, but a set of microinverters are all still generating enough power to convince each other that the grid is still up. This could present a hazard to utility workers! Our Islanding Detector automatically shuts down the inverter if it detects this situation.

  • Cause: The inverter detected that the actual AC grid waveform has disappeared, and automatically shut down.
  • Resolution: The microinverter will resume normal production when the grid (AC) waveform returns.

Error: Over Temperature


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  • Cause: The inverter’s internal temperature was too high, and it stopped automatically.
  • Resolution: The microinverter will resume normal production when the temperature drops to a safe level.

Error: AC Frequency Out of Range While Reconnecting


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Note - If an inverter stops producing because the AC waveform exceeded the frequency or voltage limits, it will reconnect with stricter limits to avoid repeatedly cycling on and off.

  • Cause: the frequency of the AC waveform is too high or too low for the regulatory region selected for your site.
  • Resolution: Make sure the correct regulatory region is selected for your site, using the sunMAX Install application for Android. Select your site, then tap “Site / Customer Info”. If the correct region is selected, check the AC frequency and contact your utility to ensure the grid is within specifications.

Error: AC Frequency Discontinuity


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  • Cause: the frequency of the AC waveform changed abruptly and the inverter stopped automatically.
  • Resolution: Make sure the correct regulatory region is selected for your site, using the sunMAX Install application for Android. Select your site, then tap “Site / Customer Info”. If the correct region is selected, check the AC frequency and contact your utility to ensure the grid is within specifications.