ErrorCodeDoctor
Daikin · Air Conditioner

Daikin Air Conditioner A5 error code

Difficulty: Easy · Cost: $0–$150 · Duration: 15–30m

The A5 error means your Daikin air conditioner's freeze-up protection activated in cooling mode or high pressure control activated in heating mode. The most common user-fixable cause is a clogged air filter restricting airflow — this causes the indoor coil to freeze up in cooling mode. Clean the air filter first. If the filter is clean the indoor heat exchanger thermistor may be defective and a technician is needed.

Common causes

  • Air filter is clogged with dust reducing airflow over the indoor coil and causing freeze-up
  • Short circuit airflow — air is being recirculated without passing over the coil properly
  • Defective indoor unit heat exchanger thermistor

How to fix it

  1. 1

    Turn off the air conditioner

  2. 2

    Remove the air filter and clean it — rinse under running water and allow it to dry fully before reinserting

  3. 3

    Check that nothing is blocking the air inlet or outlet of the indoor unit

  4. 4

    Allow the indoor coil to defrost completely before restarting

  5. 5

    Restart the air conditioner and check if A5 returns

  6. 6

    If the filter is clean and the error persists contact a qualified technician to check the heat exchanger thermistor

Related Daikin Air Conditioner error codes

1

A0

An external protection device connected to the indoor unit has been activated

hard
2

A1

A fault was detected in the indoor unit PCB (control board)

hard
3

A3

The drain level control system has detected an abnormality — drain may be clogged

medium
4

A6

The indoor unit fan motor has a fault

hard

A5 error — frequently asked questions

What does the A5 error mean on a Daikin air conditioner?

Freeze-up protection (cooling) or high pressure control (heating) has activated — check the air filter

What causes the A5 error?

The A5 error is usually caused by: Air filter is clogged with dust reducing airflow over the indoor coil and causing freeze-up; Short circuit airflow — air is being recirculated without passing over the coil properly; Defective indoor unit heat exchanger thermistor.

Can I fix the A5 error myself?

Yes — this is rated an easy fix that most people can do themselves, typically in 15–30m.

How much does it cost to fix the A5 error?

Fixing the A5 error on a Daikin air conditioner typically costs $0–$150, depending on parts and whether you do it yourself or hire a technician.

Is it safe to keep using my air conditioner with the A5 error?

In most cases yes, but it's best to address the A5 error soon — see the fix steps below to resolve it.