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ErrBase

SolarEdge Inverter 18XF5 Error Code: DC Injection Fault

Quick Answer

SolarEdge 18XF5 is a DC injection fault - the inverter detected that DC current was leaking into the AC grid output above the permitted level (typically 0.5% of rated current per IEC 61727 and UL 1741). This is almost always caused by a failed internal component, most commonly an output capacitor or IGBT. A power cycle will rarely clear this fault.

SolarEdge 18XF5 is a DC injection fault - the inverter detected that DC current was leaking into the AC grid output above the permitted level (typically 0.5% of rated current per IEC 61727 and UL 1741). This is almost always caused by a failed internal component, most commonly an output capacitor or IGBT. A power cycle will rarely clear this fault. The inverter typically requires board-level repair or replacement, and the fix must be performed by a qualified solar technician.

SolaredgeInverterSeverity: highDifficulty: advanced55% DIY Success
Time to Fix
120–480 min
Difficulty
advanced
Parts Cost
$800 – $2500
Tools Needed
SetApp (SolarEdge mobile app), SolarEdge monitoring portal access

What Does the 18XF5 Code Mean?

18XF5 is a hardware fault indicating failed output capacitors or IGBT components causing DC to leak into the AC output. A power cycle is unlikely to help. Professional service is required.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

Failed output capacitor40%
IGBT transistor fault24%
Firmware fault causing false detection22%
Wiring insulation breakdown14%

Symptoms You May Notice

  • Inverter stops producing power
  • LCD shows 18XF5
  • Fault does not clear after power cycle
  • No visible external cause (weather or grid is normal)

Can you reset a Solaredge inverter to clear the 18XF5 code?

Attempt reset by turning off the AC disconnect for 5 minutes and turning it back on. If 18XF5 clears, monitor for 24 hours. If the code returns, the inverter has a hardware failure and a reset will not provide a lasting fix.

Tools Required for Diagnosis

SetApp (SolarEdge mobile app)SolarEdge monitoring portal access

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

1

Turn off the AC disconnect switch, wait 5 minutes, and turn it back on

Turn off the AC disconnect switch, wait 5 minutes, and turn it back on. Allow the inverter 5 minutes to complete its startup and self-test sequence.

2

Check whether the inverter is within its warranty period

3

If out of warranty, contact your solar installer for a service visit

4

Ask the technician to check firmware version before condemning

5

Compare repair cost versus replacement

Replacement Parts

If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.

Part Name
SolarEdge Inverter (replacement unit)SE7600H-US (model-specific) · $800–$2500

Repair vs. Replace Calculator

Appliance Age (Years)7 Yrs
Labor Approach
Our Verdict
REPLACE
Estimated Cost: $1650 (Parts) vs $1650 (New Machine)

Frequently Asked Questions

What is DC injection in a solar inverter?
DC injection means a small amount of DC current is mixing into the AC output of the inverter. This is harmful because DC on the AC grid can saturate transformer cores, damage appliances, and create safety hazards. All grid-tied inverters are required by standards to keep DC injection below 0.5% of rated current.
Can a 18XF5 fault damage my electrical system?
The inverter disconnects from the grid the moment the DC injection is detected, so the risk of damage to your home electrical system is minimal. The shutdown is precisely designed to prevent contamination of the AC circuit.
Is 18XF5 covered under the SolarEdge warranty?
If your inverter is within the warranty period (12 years standard), yes. SolarEdge will repair or replace the inverter at no cost. Call 1-510-498-3200 with your inverter serial number and fault code.
How long will the inverter be down for a 18XF5 repair?
If a replacement unit is available, a field swap by a technician typically takes 2 to 4 hours. If the unit needs to be sent in for board-level repair, the turnaround is typically 2 to 4 weeks. During that time your solar system will produce no power.
My SolarEdge is only 3 years old and shows 18XF5. How did it fail this quickly?
Component failures can occur early due to manufacturing defects, power surges, or overheating from poor installation (blocked ventilation). At 3 years old this is almost certainly a warranty-covered failure. Contact SolarEdge immediately.

Related Solaredge Inverter Error Codes

Code: HUBSolarEdge Inverter Error Codes: Complete Fault Guide for SE SeriesCode: 18XB5SolarEdge Inverter 18XB5 Error Code: Internal Hardware FaultCode: RESETSolarEdge Inverter Error Codes: Complete Fault Guide for SE Series

Same Fix on Other Brands

SMA Arc Fault / DC Injection:

Models Known to Experience 18XF5 Errors

This repair applies to most Solaredge inverters with this error code. Common model numbers include:

SE7600H, SE10000H, SE6000H, SE3000H

Last verified for technical accuracy on March 14, 2026