Warning What does this mean?

Your system is down or running degraded, but this is not an immediate safety danger. Work through the safe steps below.

Solis Inverter UN-G-V Error: Meaning, Causes & Safe Fix

Grid voltage dropped below your Solis inverter's safe limit, so it disconnected. Common during brownouts or weak-grid conditions.

What should I do first?

Two quick questions — we'll point you to the right starting point.

Is this code still showing on your inverter's display?

What this code means

UN-G-V means 'under grid voltage' (variants 01/02). When the AC grid voltage falls below the protection threshold, the inverter stops feeding power and raises this alarm, reconnecting automatically when voltage recovers.

What is this downtime costing you?

Rough estimate while your system isn't producing. Adjust the numbers to match your setup.

System size (kW) Peak sun hours / day Electricity rate ($/kWh)

–per day

–per week

–per 30 days

≈ – kWh of lost production per day.

Estimate only — assumes ~80% real-world output vs. nameplate. Actual losses depend on weather, shading, panel direction, and your tariff.

Common causes

Utility brownout or weak grid, common at peak demand times
High-resistance AC connection dropping voltage before it reaches the inverter
Protection voltage limits set tighter than local conditions require

Safe steps to try

Work top to bottom, ticking off each step as you complete it. 0 of 5 done.

Check whether neighbors are affected or the utility reports low voltage
Note the exact code and the time it appeared
Perform one documented restart (AC OFF, DC OFF, 5-minute wait, DC ON, AC ON)
If it clears and does not return, it was most likely a grid event
If it persists, contact your installer — do not adjust protection limits yourself

Is your inverter still under warranty?

Before paying for a repair, check — your installer may fix this free.

Brand Year installed

Based on typical standard warranty terms — always confirm with your warranty card or installer paperwork, as terms vary by model, region, and purchase date.

When to call an electrician

Call your installer if the fault repeats — the AC wiring or protection limits may need professional attention. If the whole area has low voltage, report it to your utility instead.

Frequently asked questions

Will it fix itself?

Usually yes — the inverter reconnects automatically once grid voltage recovers. If it keeps happening, the underlying cause needs attention.

Is under-voltage harmful?

The inverter is protecting itself and the grid by disconnecting. There's no danger, but repeated events cost you production.

My lights flicker when this happens — is it related?

Flickering lights plus UN-G-V point to a weak or unstable grid supply. Note the times it happens and report both symptoms to your installer or utility.

Need a professional?

This fault may need professional diagnosis. Contact a qualified solar electrician in your area.

Sources: meaning and troubleshooting verified against the manufacturer's documentation — Solis S5-GR3P(3-13)K Three Phase Inverter User Manual (Ginlong Solis), Table 9.1