Fault Reasons: Inverter detected the impedance of PV+ and PV - to the ground is too low (STS＜50KΩ，STT＜100KΩ).

• 1. Check the grounding of the PV panel's frame and bracket and make sure the impedance to the ground is less than 10Ω;
  

• 2. Swap to insert the PV string into DC connectors one by one in turn until all PV strings have been tested in all DC connectors,if one PV string reports this fault in all DC connectors, this PV string may have the above-described problem, and vice versa;
  

• 3. Use a multi meter to measure if there's voltage between the N and PE cable;

• 4. If the above steps have been checked and excluded, please contact sunways after-sales team at service@sunways-tech.com or +86 400 9922 958 for help.

Fault Reasons: The output DC component is over the selected country's limitation.

• 1. Turn off the DC switch and AC breaker;
  

• 2. Wait about 5 mins and turn on the AC breaker and DC switch to check if this fault still exists, if it is, please contact sunways after-sales team at service@sunways-tech.com or +86 400 9922 958 for help.

Fault Reasons：Inverter will show "Grid Frequency Fault" when detected the AC frequency is out of range of selected country's limitation.

• 1. Check if the safety country selected is comply with the installation place.
  

• 2. The frequency fault is usually caused by the grid unstable, when the grid backs normal, this fault will be disappear as well.
  

• 3. Check the frequency on the display to see if it is within the range of limitation, if it is, please contact sunways after-sales team at service@sunways-tech.com or +86 400 9922 958 for help.

Fault Reasons：Inverter will show "Grid Voltage Fault" when detected the AC voltage is out of range of selected country's limitation.

• 1. Check if the impedance of the output cable is too high to lead to the grid voltage increased, change a thicker cable to check if the problem is solved or not;
  

• 2. If you are using an aluminum cable, please change to copper cable lower down the voltage;
  

• 3. If this fault caused by the grid voltage in the installation place is over the limitation, please contact sunways after-sales team at service@sunways-tech.com or +86 400 9922 958 for help.

Fault Reasons：Inverter will show "Mains Lost" when the AC grid disconnected.

Fault Reasons：The inverter will show "GFCI Fault" if it detects the earth leakage current exceeded the limitation.

• 1. Insert the PV string separately in turn and if the inverter reports this error when one of the PV strings is inserted, please check if this PV string has the water seepage or broken skin problem;
  

• 2. If this fault only appears in the morning or rainy day when the air humidity is very high, this fault is mostly caused by the panel aging and it will disappear when the weather is sunny；
  

• 3. Please contact sunways after-sales team at service@sunways-tech.com or +86 400 9922 958 if all steps above have been checked and excluded.

Fault Reasons：The inverter will show "PV Over Voltage" if it detects the PV input voltage exceeded the limitation (STS@600V, STT@1100V).

• 1. Check the number of PV panels connected in each string and make sure the total open circuit voltage is within the limits which Sunways specified in the datasheet, if yes, please remove several pieces panel until it within the range;
  

• 2. If the PV string is measured within the limits that Sunways specified, please check if it is close to the voltage on the inverter display;
  

• 3. If it doesn't match, please contact sunways after-sales team at service@sunways-tech.com or +86 400 9922 958 for help.

Fault Reasons：

• 1. The voltage of PV string exceeds the inverter max allowed input voltage;
  

• 2. Inverter control board is operating abnormal.
  

• 1. Use a multi-meter to measure the voltage of the PV panels to see if it exceeds the inverter max allowed input voltage;
  

• 2. Reduce the solar panels in each PV string moderately to make sure it's within the inverter max allowed input voltage;

• 3. If the measured PV string voltage is within the range but this fault still exists, please contact sunways after-sales team at service@sunways-tech.com or +86 400 9922 958 for help.