The Ultimate Daikin Air Conditioner Troubleshooting Guide

May 13, 2025

Imagine it is a hot summer day, and you are going about your day. Suddenly, your Daikin air conditioner has stopped working or is not performing as it should. Frustrating right? Daikin is renowned for its innovative technology, energy efficiency, and reliable performance. Fortunately, not every issue requires a costly repair or a professional visit.

Many common problems with Daikin air conditioners can be easily identified and resolved on your own. This guide will walk you through practical steps to get your AC back on track when you encounter issues.

Quick Overview of Daikin Systems

Before diving into troubleshooting, it is important to understand the kind of Daikin air conditioner you own. The company offers several types of systems, including split systems for single rooms, multi-split systems that connect multiple indoor units to one outdoor unit, and ducted systems for whole-home climate control. Not sure a Daikin system is the right fit for your home? See our guide on the reasons to choose a Daikin air conditioner.

Each system features distinct components, settings, and potential challenges. Knowing your air conditioner unit’s specific model will help you quickly pinpoint the cause of the problem and apply the right fix. Always refer to your user manual for model-specific information, as it is your first line of defence in effective troubleshooting.

Top 5 Common Daikin AC Problems & How to Fix Them

Let us dive into the most frequent Daikin air conditioner problems and how to fix them.

AC Not Turning On

If your air conditioner is not powering on, start with the basics like checking if the unit is properly plugged in, ensuring the power outlet is working, and looking for a tripped circuit breaker or a blown fuse. Also, check the remote for dead batteries or any issues with the signal transmission. If the issue persists after these checks, it might be an internal fault that requires professional service.

Not Cooling or Heating Properly

When you encounter an issue like your AC runs but does not cool or heat effectively, the most common cause is a clogged air filter restricting the airflow. Cleaning or replacing the filter can often restore performance. Also, make sure the thermostat is set to the correct mode and the temperature is appropriately adjusted. Additionally, check the outdoor units for any obstructions like leaves, dirt, or debris. If the airflow seems clear but performance is still lacking, then low refrigerant levels or compressor issues could be the cause. These problems require a licensed technician to inspect and fix them safely.

Leaking Water

Water leaking from your indoor units is often caused by a blocked condensate drain line. This prevents proper drainage and leads to overflow due to dust and mold buildup. For this, identifying the AC leaking water causes and fixes is essential. You can fix it by gently flushing the drain line to have it cleaned by a technician. Besides, improper installation, such as tilted units, can also cause leaks. Moreover, in colder months, frozen coils may thaw and drip water. In such cases, turning the unit off and letting it defrost before restarting can help. That said, persistent leakage issues should always be reported and checked by a professional.

Unusual Noises

Noises like rattling, buzzing, and hissing can usually mean loose screws or panels, electrical issues or a failing motor or a refrigerant leak. While loose screws can be tightened easily, buzzing, and hissing require immediate professional attention. At the same time, debris caught in the fan blades can also cause abnormal sounds, so look for any visible blockages or damage by turning off the unit. Regular servicing can help catch these issues early and prevent costly repairs in the future.

Remote Control Not Working

If your Daikin remote is not working, start by replacing the batteries and make sure you are pointing directly at the indoor unit without anything blocking the signal. In some cases, the remote may have accidentally entered the “lock” mode. Look for a lock icon and consult the manual to deactivate it. In addition, interference from fluorescent lighting or other electronics can also disrupt the signal. If any of these steps do not resolve the issue, try resetting the remote, or use Daikin’s mobile app as an alternative way to control the unit.

If you find this blog helpful, you might also want to read about common air conditioner problems and their solutions for more tips and troubleshooting advice.

Daikin Error Codes: Full Reference Table

Indoor Unit Error Codes (A & C Series)

Code	MeaningAir Conditioner Size	Likely Fix
A1	Indoor unit PCB (control board) fault	Power cycle the unit; if it returns, the control board needs replacing call a technician
A3	Drain pump or drain level fault	Clean the drain line and check the drain pump; persistent faults need a technicianx`x`
A5	Indoor heat exchanger overheating or freezing	Check for a dirty air filter or blocked airflow; clean or replace the filter
A6	Indoor fan motor locked or overloaded	Check for obstructions in the fan; if none, the motor likely needs replacing
C4	Indoor heat exchanger thermistor fault	Usually a disconnected or faulty sensor needs a technician
C9	Room temperature sensor fault	Same as above sensor disconnection or short circuit, needs professional inspection

Outdoor Unit Error Codes (E, F & H Series)

Code	MeaningAir Conditioner Size	Likely Fix
E1	Outdoor unit PCB fault	Power cycle first; recurring faults need board-level repair
E3	High pressure switch activated	Often a dirty/blocked condenser coil — clean the outdoor unit and ensure 50cm clearance on all sides
E4	Low pressure switch activated	Usually low refrigerant or a blocked line — needs a licensed technician (refrigerant handling requires certification)
E5	Compressor overheating or motor overload	Check outdoor unit airflow and clearance; persistent fault needs a technician
E6	Compressor not starting	Electrical or compressor fault — needs a technician
E7	Outdoor fan motor locked or not running	Check for debris around the fan; if clear, the motor needs inspection
F3	Discharge pipe temperature too high	Can be caused by low refrigerant, a blocked condenser, or high ambient temperature — turn off and let it cool; call a technician if it recurs
H0	Compressor sensor system fault	Needs a technician — usually a wiring or PCB issue

System and Communication Error Codes (U Series)

Code	MeaningAir Conditioner Size	Likely Fix
U0	Low refrigerant / suction pipe temperature abnormal	Refrigerant leak or shortage needs a licensed technician to test and recharge
U2	Power supply problem	Check voltage supply and wiring connections; call an electrician if the supply is unstable
U4	Indoor and outdoor units not communicating	Often a temporary glitch after a power cut full power cycle (both units off at the breaker for 3 minutes) usually clears it; if it returns immediately, check the inter-unit wiring

My Error Code Isn't Listed What Now?

Daikin has close to 100 distinct codes across its residential, ducted, and VRV ranges, and not every code appears on every model. If your display is showing something not listed above, check your unit’s manual for the exact code table for your model, or see the When to Contact a Technician section below for next steps.

Understanding Daikin Error Codes

Daikin air conditioners often display error codes to help identify certain issues within the system. The codes usually appear on the indoor unit’s display panel or the remote-control screen. Consult your model’s user manual to interpret these codes. Each code represents a specific issue, such as sensor malfunctions, refrigerant problems, or communication errors. While minor errors can be resolved by resetting the unit, persistent ones require professional assistance. If the code reappears after a reset or if you are unsure about its meaning, it is recommended to contact a Daikin technician for a professional diagnosis.

For further insights, we recommend reading our detailed guide on the 10 signs your AC requires repair to ensure optimal performance and longevity

How to Reset a Daikin Air Conditioner by System Type

Resetting a Wall-Mounted Split System

Turn off the Daikin unit using the remote, then switch off its circuit breaker. Wait 30–40 seconds before restoring power. Turn the breaker back on, then restart the air conditioner with the remote and check whether normal operation returns.

Resetting a Ducted System

For a Daikin ducted system, switch the system off using its wall controller before turning off the dedicated circuit breaker. Wait 30–40 seconds, restore power, and turn the system back on through the controller. If problems continue, check the manual or contact a technician.

Resetting a Cassette or Floor Console Unit

Switch off the cassette or floor console unit using its controller or remote. Turn off the connected circuit breaker and wait 30–40 seconds. Restore power and restart the unit. If the error or operating problem remains, professional inspection may be necessary.

Resetting a Multi-Split System

Turn off all indoor units connected to the multi-split system. Switch off the appropriate circuit breaker and wait 30–40 seconds. Restore power, then restart the indoor units individually. If an error code returns, check the model manual or arrange professional servicing.

Soft Reset via the Remote (No Breaker Needed)

For a simple soft reset, turn the Daikin air conditioner off using the remote or wall controller. Wait briefly before turning it back on. This can clear minor temporary glitches, but persistent errors may require a full power reset or professional diagnosis.

Essential Maintenance Tips to Avoid Issues

Regular maintenance of your Daikin air conditioner is essential for ensuring optimal performance and preventing unexpected breakdowns. Clean or replace the air filter every two or four weeks, especially during peak usage periods. Make sure the indoor unit is not blocked by furniture or curtains and the outdoor unit is clear of dirt and other debris to ensure proper ventilation. Most importantly, schedule professional servicing at least once a year to ensure overall system health and long-term reliability. Avoid these common AC maintenance mistakes to get the most out of your system.

When to Contact a Technician

If your unit continues to show error codes, or cooling or heating issues despite resets, or if it starts emitting unusual smells, turn it off immediately. Not sure whether it’s worth repairing or replacing an ageing unit? Issues like low refrigerant levels, electrical faults, or internal damage require specialized training to address them.

Contact an authorised Daikin technician to ensure the best and accurate repairs.

Frequently Asked Questions

1. What Is the Most Common Problem With a Daikin Air Conditioner?

A common Daikin AC problem is poor cooling caused by clogged air filters. Other issues include power problems, refrigerant leaks, thermostat faults, water leaks, and unusual noises.

2. How Do I Reset My Daikin AC Without the Remote?

Turn off the AC at the circuit breaker, wait 30–40 seconds, then restore power. Afterward, turn the unit on using its wall controller or available controls.

3. What Does an Error Code on My Daikin AC Mean?

A Daikin error code identifies a possible system problem, such as a sensor, refrigerant, or communication fault. Check your model’s manual and contact a technician if it persists.

4. Why Is My Daikin Air Conditioner Not Turning On?

Check the power supply, outlet, circuit breaker, fuse, and remote batteries first. If these are working but the AC remains off, an internal fault may require professional service.

Conclusion

Regular maintenance and timely troubleshooting can keep your Daikin air conditioner running smoothly all year round. Addressing minor issues early can help you avoid bigger problems down the road. If the situation feels beyond your control, never hesitate to call a qualified technician.

Veer Pratap

CEO / Director (Refrigeration A/C Supervisor, Electrician)