Daikin AC L5 Error — DC Overcurrent Fix

What it means

L5 on a Daikin AC means the inverter has detected an overcurrent on the DC bus — too much current is flowing inside the inverter.
The unit shuts down to protect the compressor and inverter board.
L5 usually means a failing compressor or a faulty inverter board.
Service is required.

Affected Models

Daikin FTKF Series
Daikin FTKG Series
Daikin ATKF Series
Daikin FTXM Series
Daikin Inverter Split AC (all models)

Common Causes

Failing or seized compressor causing high current draw
Inverter IGBT module fault
Compressor winding short causing brief overcurrent
Refrigerant overcharge increasing compressor load
Failed inverter board (rare — usually downstream effect)

How to Fix It

Power off and do not restart.

Switch off at the breaker and leave off until service.
Each L5 event stresses the compressor windings — repeated starts can permanently damage the compressor.
Note recent service history.

L5 within weeks of a recharge often points to refrigerant overcharge — the technician overfilled.
Within months of a compressor replacement, it may be a defective compressor.
Note this for the new service technician.
Check breaker and supply voltage.

While not the typical cause, a weak breaker that allows under-voltage can stress the compressor and indirectly trigger L5.
Confirm the breaker is rated correctly and trips reliably under fault.
Book Daikin service immediately.

L5 needs a technician with insulation tester and inverter diagnosis tools.
They will isolate compressor vs inverter and quote accordingly.
Compressor replacement: USD 800–1,500 fitted.
Inverter board: USD 350–700.
Get a written diagnosis before authorising repair.

Compressor replacement on an older AC (8+ years) often pushes total repair past the cost of a new system.
Get the technician to commit to a diagnosis before authorising parts.

When to Call a Professional

L5 is not user-resolvable.
Continued attempts to start the AC after L5 risk catastrophic compressor or inverter damage.
Book Daikin-authorised service before the next start attempt.

Frequently Asked Questions

Will my Daikin restart on its own after L5?

Some L5 events allow restart after a cool-down.
Do not let it.
Each unsuccessful start strains the compressor windings — repeated starts can turn a marginal compressor into a dead one.
Always switch off after L5 and wait for service.

Is L5 covered under warranty?

L5 from a manufacturing defect (compressor or inverter) is covered under Daikin's standard warranty (typically 5 years on compressor in many markets, 1–2 years on PCBs).
Damage from improper installation or refrigerant overcharge is not covered.