FAQ & error codes
The explanations are excerpts from user manuals.
What does F01 mean on the SUN 120–136K string inverter?
F01 means the DC input polarity is reversed. Check the polarity of the PV input before restarting the inverter.
What does F02 — DC insulation impedance permanent fault — mean?
F02 means the inverter detects a persistent problem with the DC-side insulation impedance. Check the inverter grounding and the PV-side insulation and ground connection. If the fault remains, contact the installer or service team.
What does F24 — DC Insulation Fault — mean?
F24 means the PV isolation resistance is too low. Check that the connections between the PV panels and the inverter are firm and correct. Check whether the inverter PE cable is connected to ground.
What does F27 — DC end insulation error — mean?
F27 is reported by Deye as a DC-end insulation error. Restart the inverter only after the DC-side insulation and grounding have been checked; if the fault remains, contact the installer or Deye service.
What does F05 mean on the SUN 120–136K string inverter?
F05 is a memory read (EEPROM) error. Restart the inverter. If the fault returns, contact the installer.
What does F06 mean on the SUN 120–136K string inverter?
F06 is a memory write (EEPROM) error. Restart the inverter. If the fault remains, contact the installer.
What does F16 mean on the SUN 120–136K string inverter?
F16 indicates an AC leakage-current / GFCI (RCD) fault. The manual recommends checking the DC supply or PV modules and the leakage-current sensing circuit. If it persists after restart, contact the installer.
What does F20 mean on the SUN 120–136K string inverter?
F20 is a DC hardware overcurrent fault. Check that PV output current is within the permitted range and have the DC current-sensing circuit checked if the fault repeats.
What does F35 mean on the SUN 120–136K string inverter?
F35 means the AC grid is unavailable. Check that the grid supply is present and that the AC connection and protection devices are correctly connected and switched on.
What do F41, F43 and F45 mean?
These codes indicate AC line overvoltage on different phase pairs. Check the AC voltage protection settings, cable sizing and the voltage measured at the inverter and meter.
What do F42, F44 and F46 mean?
These codes indicate AC line undervoltage on different phase pairs. Check the AC voltage settings and make sure all AC cables are firmly and correctly connected.
What do F47 and F48 mean?
F47 means grid frequency is too high; F48 means it is too low. Check the actual grid frequency and the configured grid-code / frequency limits.
What do F55 and F56 mean?
F55 indicates DC-bus voltage is too high and F56 indicates DC-bus voltage is too low. If either code remains after a restart, the inverter should be checked by the installer or service team.
What does F63 mean on the SUN 120–136K string inverter?
F63 is an arc-fault indication. Inspect the PV string wiring and connectors for loose, damaged or poorly terminated connections before returning the system to service.
What does F64 mean on the SUN 120–136K string inverter?
F64 means the IGBT heatsink temperature is too high. Check ventilation, ambient temperature and whether the cooling path is obstructed. Allow the inverter to cool before restarting.
Does the SUN 120–136K monitor DC terminal insulation impedance?
Yes. Deye lists DC terminal insulation impedance monitoring as an equipment-protection function for this series. Related insulation faults can therefore appear as codes such as F02, F24 or F27.
What does W02 mean on the SUN-100/125K hybrid inverter?
W02 is an internal-fan warning. Check that the fan path is clear and that the fan is operating normally.
What do W03, W04, W05 and W06 mean on the hybrid inverter?
W03 concerns grid phase sequence, W04 indicates meter communication is offline, W05 indicates the CT direction may be incorrect, and W06 is a CT connection warning. Check the relevant grid, meter and CT wiring.
What does F01 mean on the SUN-100/125K hybrid inverter?
F01 indicates reversed DC input polarity. Check the PV input polarity before restarting the inverter.
What does F02 — DC insulation failure — mean on the SUN-100/125K hybrid inverter?
F02 indicates a DC insulation fault. Check whether the PV array is correctly grounded and whether the impedance between the PV side and ground is normal.
What does F03 — GFDI failure — mean on the SUN-100/125K hybrid inverter?
F03 indicates a ground-fault detection issue. Check PV grounding, the impedance between PV and ground, and whether leakage current is present.
Does the SUN-100/125K hybrid inverter detect insulation impedance?
Yes. Deye lists insulation impedance detection as an equipment-protection function for the SUN-100/125K-SG02HP3-EU-GM10.
What should I do when a fault does not clear?
Record the inverter model, serial number and fault code. Perform only the checks described for that code. If the fault remains, contact a qualified installer or Deye service.