Deye / Sunsynk error codes explained

What 18 Deye / Sunsynk inverter fault and error codes mean, in plain English, with safe checks you can do and when to call a licensed electrician.

Safety first: never open the switchboard, remove covers, or pull apart or disconnect the inverter, batteries, isolators or wiring. Only use the switches and buttons described here. Anything else must be done by a licensed electrician. Call 1300 209 503 or book a service request.

Guide only. This information is a general guide taken from manufacturer documentation. All electrical work must be performed by a licensed electrician. Never open your inverter, battery or switchboard. If you see smoke, smell burning or see damage, keep clear and call 000.

Common Deye / Sunsynk questions

What does Deye / Sunsynk F18 "AC over current fault of hardware" mean?

AC over current fault of hardware Note the code, then restart the system once using the owner shutdown/start-up steps in your manual This is a guide only; any electrical work must be done by a licensed electrician.

What does Deye / Sunsynk F20 "DC over current fault of the hardware" mean?

DC over current fault of the hardware Note the code, then restart the system once using the owner shutdown/start-up steps in your manual This is a guide only; any electrical work must be done by a licensed electrician.

What does Deye / Sunsynk F22 "Tz_EmergStop_Fault" mean?

Tz_EmergStop_Fault Note the code, date and time and check the monitoring app This is a guide only; any electrical work must be done by a licensed electrician.

What does Deye / Sunsynk F29 "Parallel CANBus fault" mean?

Parallel CANBus fault Note the code, then restart the system once using the owner shutdown/start-up steps in your manual This is a guide only; any electrical work must be done by a licensed electrician.

What does Deye / Sunsynk F34 "ACOvercurrent fault" mean?

ACOvercurrent fault Note the code, date and time and check the monitoring app This is a guide only; any electrical work must be done by a licensed electrician.

Need help with this fault?

Get a licensed electrician to call you back.

Total Solar can help: our licensed electricians install and service systems. Based in Ellenbrook, WA, with Victoria and Queensland also available.

Or call 1300 209 503

Sources

Meanings are summarised from these manufacturer documents. Check your own model's manual, as codes vary between models and firmware versions.

Deye SUN-(3.6-6)K-SG04LP1 User Manual, 7 Fault information

Deye / Sunsynk is a trademark of its owner. Total Solar is not affiliated with the manufacturer unless stated. All fault code guides

Code	Message & meaning	Model	Type
F08Safety-Critical	GFDI _Relay_Failure GFDI _Relay_Failure What you can do Keep clear and do not touch the inverter or cabling Note the code, date and time Call a licensed electrician or Total Solar - this alarm means current may be leaking to earth SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F18Fault	AC over current fault of hardware AC over current fault of hardware What you can do Note the code, then restart the system once using the owner shutdown/start-up steps in your manual If the code comes back, call your installer - this is an internal fault that needs a licensed electrician or the manufacturer SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F20Fault	DC over current fault of the hardware DC over current fault of the hardware What you can do Note the code, then restart the system once using the owner shutdown/start-up steps in your manual If the code comes back, call your installer - this is an internal fault that needs a licensed electrician or the manufacturer SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F22Fault	Tz_EmergStop_Fault Tz_EmergStop_Fault What you can do Note the code, date and time and check the monitoring app Restart the system once using the owner shutdown/start-up steps in your manual if it allows If it comes back, call your installer SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F23Safety-Critical	AC leakage current is transient over current AC leakage current is transient over current What you can do Keep clear and do not touch the inverter or cabling Note the code, date and time Call a licensed electrician or Total Solar - this alarm means current may be leaking to earth SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F24Safety-Critical	DC insulation impedance failure DC insulation impedance failure What you can do Do not touch the panels, rooftop isolators or DC cables Note the code and whether it appears in wet weather or early morning - this helps the electrician If it clears by itself once things dry out, still let us know if it keeps returning Call a licensed electrician or Total Solar - insulation and earth faults need testing with proper equipment SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F26Warning	The DC busbar is unbalanced The DC busbar is unbalanced What you can do Check that your home Wi-Fi/internet is working and restart your router Wait an hour - monitoring often reconnects by itself If the inverter screen also shows a fault, or the alarm stays for more than a day, call your installer SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F29Fault	Parallel CANBus fault Parallel CANBus fault What you can do Note the code, then restart the system once using the owner shutdown/start-up steps in your manual If the code comes back, call your installer - this is an internal fault that needs a licensed electrician or the manufacturer SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F34Fault	ACOvercurrent fault ACOvercurrent fault What you can do Note the code, date and time and check the monitoring app Restart the system once using the owner shutdown/start-up steps in your manual if it allows If it comes back, call your installer SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F35Info	No AC grid No AC grid What you can do Check whether the rest of your house or street has power, and check your network operator's outage map Check the switchboard for a tripped solar/inverter breaker - reset it once only; if it trips again, leave it off and call an electrician Once normal power is back the inverter usually reconnects on its own within a few minutes If the power is normal but the alarm stays, call your installer SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F41Fault	Parallel system stop Parallel system stop What you can do Note the code, date and time and check the monitoring app Restart the system once using the owner shutdown/start-up steps in your manual if it allows If it comes back, call your installer SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F42Warning	AC line low voltage AC line low voltage What you can do This is usually caused by the mains supply, not the solar system The inverter normally reconnects by itself once grid voltage is back in range If it happens often (especially on sunny afternoons), note the times and call your installer - they can check the voltage and settings and talk to the network if needed SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F47Warning	AC over frequency AC over frequency What you can do This is caused by the mains frequency moving outside the allowed range, usually briefly The inverter reconnects by itself once the grid is stable If it keeps happening, note the times and call your installer SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F48Warning	AC lower frequency AC lower frequency What you can do This is caused by the mains frequency moving outside the allowed range, usually briefly The inverter reconnects by itself once the grid is stable If it keeps happening, note the times and call your installer SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F56Fault	DC busbar voltage is too low DC busbar voltage is too low What you can do Note the code, then restart the system once using the owner shutdown/start-up steps in your manual If the code comes back, call your installer - this is an internal fault that needs a licensed electrician or the manufacturer SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F58Fault	BMS communication fault BMS communication fault What you can do Check the app - the battery may show as offline or with no state of charge Restart the system once using the shutdown and start-up steps in your owner's manual (battery last off, first on, unless your manual says otherwise) If the alarm comes back, call your installer - battery communication cables must be checked by them SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F63Safety-Critical	ARC fault ARC fault What you can do Keep clear of the inverter, panels and DC cables, and do not touch any isolators Note the code, date and time, and check whether the alarm is still showing in the app If you smell burning or see smoke, get everyone out and call 000 Call a licensed electrician or Total Solar - an arc fault means a DC wiring or connector problem that must be inspected SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter
F64Warning	Heat sink high temperature failure Heat sink high temperature failure What you can do Check from a safe distance that the inverter is shaded, has clear space around it and that nothing is blocking the vents It usually recovers once it cools down If it repeats often or you can hear a noisy/failed fan, call your installer SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk) · Guide only. All work must be done by a licensed electrician.	SUN-5K-SG04LP1 single-phase LV hybrid (also sold as Sunsynk)	Inverter

Common Deye / Sunsynk questions

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