The Complete Guide To Deye And Sunsynk Inverter Error Codes

The inverter cannot see mains power on its AC side. Usually the power is out, the solar supply main switch or the breaker between the inverter and the grid is off, or an AC connection is loose. A hybrid keeps running the backup circuit from the battery and reconnects to the grid by itself once it is back. Deye and Sunsynk both list F35 as AC_NoUtility_Fault, No AC grid.

On a three-phase unit, the grid phases are connected in the wrong order (F36), or the voltage (F37) or current (F38) across the three phases is too uneven for the inverter to run. Phase sequence is an installer wiring fix; unbalance usually means the street supply or the house loads are lopsided and often clears on its own. The manuals list the names without a description. Wiring faults need an electrician, so we treat them as a call.

On one inverter, F41 (AC_WU_OverVolt_Fault) means the grid voltage went above the export limit and it disconnected; it reconnects itself, and repeats on sunny afternoons point at the AC run or street voltage. On a site with inverters in parallel, Deye and Sunsynk describe F41 as Parallel system stop: one unit shut down so the others stopped too, and the first unit to stop is the one to look at. Over-voltage, over-current and short-circuit faults can damage hardware, so we treat them as a call.

The mains voltage at the inverter dropped below its limit, often during a brownout or when a large load starts nearby, and it disconnected. It reconnects by itself once the grid is steady; if it repeats the AC connections or the grid settings need checking. Deye and Sunsynk list F42 as AC line low voltage (AC_WU_UnderVolt_Fault).

The grid voltage on another phase went outside the inverter's limits for a moment and it disconnected: F43 and F45 too high, F44 and F46 too low, on the V-W and U-V phase pairs of a three-phase unit or a single-phase unit's second measurement. It reconnects itself. Deye's three-phase SG04LP3 manual lists F46 as a backup battery fault instead, where the batteries in a bank do not match.

The grid frequency rose above the inverter's limit for a moment and it disconnected. It reconnects by itself once the grid is steady. Sunsynk's knowledge base adds that a smaller Sunsynk running as a string inverter off a larger unit's GEN port will show F47 on purpose when the main unit shifts frequency to limit its output, which is normal.

The grid frequency dropped below the inverter's limit for a moment and it disconnected, which can happen when the network is under strain or a generator is struggling. It reconnects by itself once the grid is steady.

The current on one phase of the inverter's output (F59, F60) or in its output filter (F61) went above its limit, usually a heavy load starting or a grid disturbance on a three-phase unit. It often clears with one restart; if it repeats with normal loads the output stage needs testing. The manuals list the names only; see F58 for the U-phase code, which hybrids use for the battery link instead.

A string from the panels is connected the wrong way round at the inverter's PV input. Deye lists F01 as DC input polarity reversed. This is a wiring fault that must be corrected by an electrician; do not keep restarting it and do not touch the DC wiring.

The inverter detected power flowing back into a port it should only feed: DC fed back into its DC side (F25) or AC fed back into its output (F57), which usually means a wiring mistake such as a grid supply or another generator connected to the LOAD or GEN port. This is a wiring matter for an electrician; do not keep restarting it. The manuals list the names without a description.

The appliances on the inverter's LOAD (backup) output are drawing more than it is rated for, often an air conditioner, oven, pump or kettle starting together, so it tripped. Switch off the heavy appliances and it recovers; if it trips with ordinary loads the backup wiring and settings need checking. Deye and Sunsynk list F34 as AC Overcurrent fault or AC_Overload_Fault; F33 is the same family. Over-voltage, over-current and short-circuit faults can damage hardware, so we treat them as a call.

The inverter's ground fault detector found current flowing to earth from the solar or battery wiring (F03), confirmed a ground fault (F04), or found its own detector fuse blown (F07 on Sunsynk's list). Safety trips: do not restart it, the DC wiring needs an electrician. Deye's manual lists F07 instead as DC start failure, the unit unable to build its internal bus from the panels or battery.

The relay in the inverter's ground fault protection failed its self-test. On a single-phase unit the usual cause is the grid type setting left on split-phase (120/240 V), which Sunsynk's knowledge base says the installer fixes by setting single-phase and rebooting; otherwise the backup neutral needs earthing on split and three-phase systems, or the relay has failed. A job for the installer.

The inverter measured current leaking to earth, usually from damaged PV cable insulation, water in a connector, a panel with an earth short, or a poor earth connection. Deye and Sunsynk say to check the PV modules and cables and restart; as a safety trip, a repeat needs an electrician. F23 is the sudden transient trip, F16 (GFCI_Failure) the steady one and F21 the GFDI version.

The inverter found too little insulation between the solar wiring and earth, usually water in a connector or isolator, a chafed cable, a damaged panel, or a missing earth bond on the inverter. Morning alarms that clear by midday point to dew; one that stays is a safety issue for an electrician. F24 is the main code (DC insulation impedance failure); F02 and F27 are the same check at another stage.

The inverter's arc fault detector picked up the signature of a DC arc on the solar wiring, usually a loose or corroded connector, a poor crimp or a damaged cable, and shut down to prevent a fire. Do not restart it until an electrician has inspected the DC connectors and isolators. Deye and Sunsynk note the function was written for the US market, but it still points at a real connection fault.

The inverter's heatsink went over its temperature limit, so it cut back or stopped. Usually it is mounted in direct sun, in a hot closed space or too close to a wall, or its vents and fans are blocked with dust; it comes back once it cools. Deye and Sunsynk say to switch it off for 30 minutes and restart. If it happens on ordinary days the fan or the temperature sensor needs a look. Heat shutdowns point at a failing fan, a blocked vent or a bad installation spot, so we treat them as a call.

One of the inverter's cooling fans (W07, W08 or W09 for fans 1 to 3) has stopped or is running slow, often blocked by dust, leaves or a nest. The inverter keeps running but will overheat on hot days until the fan is cleared or replaced. These are warnings, not faults, and the manuals do not describe them; the names come from the inverter's alarm screen. Heat shutdowns point at a failing fan, a blocked vent or a bad installation spot, so we treat them as a call.

The inverter could not read (F05) or write (F06) its settings memory. One full restart often clears it; if it comes back the control board has a fault and needs the installer. The manuals list the names without a description. Internal and hardware faults need testing with the right instruments, so we treat them as a call.

A part inside the inverter has failed its self-test: the power switching module (F09 IGBT_Failure), the small power supply that runs its electronics (F10 AuxPowerBoard_Failure), or the internal protection circuits (F17, F19). Restarting is unlikely to help; the inverter needs a technician and usually a board replacement under warranty. The manuals list the names without a description.

The relays (contactors) that connect the inverter to the grid or switch the backup circuit failed their self-test: the main contactor (F11, F30) or the second one (F12, F31). A restart may clear a one-off; a repeat means a relay has failed and the inverter must not keep running, so it needs a technician. The manuals list the names without a description.

The inverter's software saw more output current than it allows for an instant, typically a large appliance starting on the backup circuit. Deye's manual says to check the backup and household loads are within range and restart. F39 (INT_AC_OverCurr_Fault) is the internal version of the same trip. A repeat at ordinary loads needs the installer. Over-voltage, over-current and short-circuit faults can damage hardware, so we treat them as a call.

The inverter's hardware protection tripped on a sudden surge of output current, usually a motor, compressor or pump starting on the backup circuit, or a grid disturbance. Deye and Sunsynk say to check the backup load is within the inverter's range and restart. If it comes back with modest loads the output stage needs testing by a technician. Internal and hardware faults need testing with the right instruments, so we treat them as a call.

On Deye's manuals F21 is a BUS overcurrent: too much current on the inverter's internal high-voltage bus, with the advice to check the PV input and the battery current settings and restart two or three times. On Sunsynk's code list the same number is the GFDI overcurrent trip described under F23. If it keeps coming back with no external cause it is a fault inside the unit for the installer.

The two halves of the inverter's internal DC bus are at different voltages. Deye and Sunsynk say to wait five minutes to see if it clears, then fully restart; on three-phase units a big imbalance between phase loads or a DC leakage fault alongside it can cause it. If it keeps coming back it is a fault inside the unit and the installer should stop restarting it and have it diagnosed.

The inverter is letting a small amount of DC into its AC output, which the grid rules do not allow, so it disconnected: F28 and F32 are the two measuring stages, F49 to F51 the grid current on each phase and F52 to F54 the inductor current. A one-off usually clears with a wait or one restart; if it keeps coming back the output stage or its sensors need testing. The manuals list the names only. DC on the AC side is a protection fault, so we treat it as a call.

The voltage on the inverter's internal DC bus went above its limit. Deye says to check the battery voltage and the PV input voltage are within range: a string with too many panels in series on a cold morning, or a battery charging above the inverter's setting, are the usual causes; otherwise it is a fault inside the unit. Do not keep restarting it; the installer checks the strings and settings.

On Deye units sold in Australia, F62 is DRMs0 stop: the demand response (DRM) port, which Australian rules require, has received the DRM0 signal to disconnect, or its plug or link is missing so the inverter thinks it has. Deye notes DRM applies only to the Australian market. Sunsynk's code list gives F62 as an inductor current fault, so on a Sunsynk unit it is a hardware trip for the installer. Internal and hardware faults need testing with the right instruments, so we treat them as a call.

The inverter cannot read its energy meter or CT clamp (W04), so the grid import and export figures in the app are wrong and export limiting may hold back production. W05 means the CT clamp is on backwards so import and export are swapped. The meter cable, or the CT's position and direction on the incoming mains, needs the installer. Sunsynk's knowledge base covers W04 and the three-phase W03.

The inverter is recording that its operating mode changed: the grid type or frequency setting was altered, the battery mode was switched to No battery, or on older firmware the work mode changed. It is a notice rather than a fault and Deye says it normally clears by itself. If it stays, a restart clears it; if it keeps coming back with no one changing settings, ask the installer.

Too much current flowed on the DC side, from the battery or the panels, for an instant. Deye and Sunsynk say the common cause is a big load starting on the backup circuit while off grid, which pulls a surge from the battery; reduce the load, check the PV and battery connections and restart. F20 is the hardware trip, F14 the software one and F40 the internal one. A repeat needs the installer. Internal and hardware faults need testing with the right instruments, so we treat them as a call.

The DC bus, which the battery feeds, has dropped too low. Nearly always the battery is flat or has switched itself off, or cannot deliver the current the inverter is asking for. Let the sun or the grid charge it; if it does not recover, the battery, its breaker, the BMS and the battery settings need checking. Deye and Sunsynk note the battery's discharge rating must be at least the inverter's. Bus faults are internal, so we treat them as a call.

The inverter has lost contact with the battery's management system (BMS) while the BMS_Err-Stop setting is on, so it stops using the battery. Usually the battery is off, the CAN or RS485 cable between battery and inverter is loose or wired wrong, or the battery protocol setting is wrong. Deye and Sunsynk list F58 as Battery_comm_Lose; the older Sunsynk code list calls it a U-phase current fault.

The inverter has been told to stop by an external signal: an emergency stop button or remote shutdown input wired to it, or a remote command from the monitoring platform. Nothing is wrong with the inverter itself; the stop input or whoever sent the command needs checking. Deye lists F22 as remote shutdown, Sunsynk as Tz_EmergStop_Fault.

On a site with more than one inverter wired in parallel, the units have lost contact with each other over the parallel CAN cable. Deye and Sunsynk say it also shows while a parallel system is starting up and clears once every unit is on; if it stays, the parallel cable and the master and slave address settings need the installer. The older code list names F29 as AC_AirSwitch_Fault.