Fujitsu AC Error Code 13 — Overcurrent Protection (OL)

What Does This Error Mean?

Error 13 on a Fujitsu AC means the overcurrent protection relay (OL relay) has tripped — the compressor or outdoor fan motor drew more current than the safe maximum. The system shuts down to prevent motor and electrical component damage. This is most often caused by high refrigerant pressure, a failing compressor, or a weak power supply.

Affected Models

Fujitsu ASTG Series
Fujitsu ASYG Series
Fujitsu AOTG Series
Fujitsu Inverter Split AC (all models)
Fujitsu General Split AC

Common Causes

High discharge pressure forcing the compressor to work harder and draw more current
Compressor starting to fail — worn bearings or winding degradation increasing current draw
Low supply voltage — insufficient voltage causes motors to draw higher current
Outdoor fan motor failing — increased friction raises current consumption
Refrigerant overcharge pushing operating pressures above design levels
OL relay itself faulty — tripping at normal current levels

How to Fix It

Switch off the AC and wait 30 minutes before attempting a restart.

Overcurrent trips generate heat in the motor windings. Allowing the system to cool fully before restarting reduces the risk of a second trip.
Check the outdoor unit for the same issues as a high pressure fault.

Clear any airflow blockages around the outdoor unit and check the condenser coil is clean. High pressure causes overcurrent — both issues often appear together.
Check the power supply voltage if you can.

Low voltage (below the AC unit's minimum — typically 198V for a 220V unit) causes motors to draw more current. If other appliances in your home seem weaker than usual, your supply voltage may be low — contact your electricity provider.
Attempt one restart and monitor for 10 minutes.

If Error 13 does not return, the trip was caused by a temporary condition such as momentary low voltage. If Error 13 returns, call a Fujitsu technician — repeated trips indicate an ongoing electrical or mechanical fault.

When to Call a Professional

Error 13 requires a Fujitsu authorised technician. Overcurrent faults related to the compressor or refrigerant system require specialist diagnosis. Do not repeatedly restart — continued overcurrent events accelerate compressor failure.

Frequently Asked Questions

Can low voltage cause Fujitsu Error 13?

Yes — when supply voltage drops below the AC unit's minimum operating voltage, electric motors must draw more current to deliver the same power. This higher current can trip the OL relay. Installing a voltage stabiliser on the AC circuit can prevent voltage-related overcurrent trips.

Is Error 13 a sign my Fujitsu compressor is dying?

Not necessarily — Error 13 can be caused by external factors like high pressure or low voltage rather than the compressor itself. However, if Error 13 appears on a unit that is 8 or more years old and both the pressure and voltage are normal, the compressor may be failing. A technician can measure compressor current draw to determine whether the compressor is the source.