Daikin Mini-Split L5 Error Code: Compressor Overcurrent Protection

Quick Answer

Daikin L5 is an instant compressor overcurrent trip - different from U0 which is a gradual overcurrent. L5 triggers when the inverter board detects a current spike exceeding the instantaneous protection threshold, usually indicating a hard electrical fault rather than a refrigerant issue. The most common cause on Daikin units over 5 years old is degraded compressor winding insulation causing a phase-to-phase short. Test compressor winding insulation with a megohmmeter between each terminal pair and to ground - readings should exceed 1 megaohm. A reading below 500K ohms confirms compressor failure. On newer units, a failed IGBT power module on the inverter board can also cause L5.

DaikinMinisplitSeverity: criticalDifficulty: advanced60% DIY Success

Time to Fix

60–480 min

Difficulty

advanced

Parts Cost

$300 – $2000

Tools Needed

Megohmmeter (500V insulation tester), Multimeter

What Does the L5 Code Mean?

L5 is an instant compressor overcurrent trip indicating a hard electrical fault - usually compressor winding short or inverter board IGBT failure.

Most Likely Causes

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

Compressor winding insulation breakdown40%

Inverter board IGBT power module failure24%

Loose compressor terminal connections14%

Incorrect voltage supply to outdoor unit12%

Compressor mechanically seized10%

Symptoms You May Notice

L5 code on indoor display
Compressor trips immediately on startup
Outdoor unit breaker may trip
Burning smell from outdoor unit in severe cases
Unit worked fine then suddenly stopped

Can you reset a Daikin minisplit to clear the L5 code?

Turn breaker off for 60 seconds. After restoring power, press Cancel on remote for 5 seconds. L5 will return immediately if the electrical fault persists.

Tools Required for Diagnosis

Megohmmeter (500V insulation tester)MultimeterClamp ammeterScrewdriver set

Diagnostic Checklist

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

Turn off the breaker

Turn off the breaker. At the outdoor unit, disconnect the compressor wiring from the inverter board. Using a megohmmeter set to 500V, measure insulation resistance between each compressor terminal pair (C-R, C-S, R-S) and between each terminal and the compressor shell (ground).

If compressor insulation is good

Check the supply voltage to the outdoor unit at the terminal block

If compressor insulation and voltage are good but L5 persists

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	OEM Number	Estimated Price
Daikin Outdoor Inverter BoardModel-specific · $300–$600	Model-specific	$300 – $600
Daikin CompressorModel-specific · $800–$2000	Model-specific	$800 – $2000

Verify part fitment for your Daikin model

Repair vs. Replace Calculator

Appliance Age (Years)7 Yrs

Labor Approach

Our Verdict

REPAIR

Estimated Cost: $1150 (Parts) vs $5500 (New Machine)

Frequently Asked Questions

Is L5 repairable or do I need a new system?

It depends on the cause. If the inverter board IGBT has failed, a board replacement ($300-600 plus labor) fixes it. If the compressor windings are shorted, compressor replacement costs $1,500-3,000 - at that point, compare against the cost of a new system, especially if the unit is over 10 years old.

Can a power surge cause L5?

Yes. A power surge can destroy the IGBT power transistors on the inverter board, which then causes L5 on the next startup attempt. If you had a storm or power outage before L5 appeared, the inverter board is the most likely failed component.

What is the difference between L5 and U0?

L5 is an instantaneous overcurrent trip - a sudden spike that triggers immediate shutdown. U0 is a sustained overcurrent condition that builds up over time. L5 usually indicates a hard electrical fault (shorted windings, failed IGBT), while U0 more commonly indicates low refrigerant charge.

Related Daikin Minisplit Error Codes

Code: HUBDaikin Mini-Split Error Codes: Complete Guide Code: U0Daikin Mini-Split U0: Low Refrigerant or Overcurrent Code: E5Daikin Mini-Split E5: Compressor Overload Code: L1Daikin Mini-Split L1: Inverter Board Fault

Models Known to Experience L5 Errors

This repair applies to most Daikin minisplits with this error code. Common model numbers include:

FTXS09LVJU, FTXS12LVJU, FTXM15QVJU, FTXM18QVJU, RXS09LVJU, RXL15QMVJU

Last verified for technical accuracy on March 15, 2026