Daikin Mini Split Troubleshooting Guide (8 Problems Fixed!)

Now that the scorching summer is here, the last thing you want is for your Daikin mini-split to fail. Its failure, however, doesn’t mean that it’s unfixable, and this Daikin mini split troubleshooting guide will confirm it.

Issues like a Daikin air conditioner that won’t turn on, cool, drain, dehumidify heat or defrost are troubleshootable. The same goes for a leaky Daikin mini split or one with an error code.

This troubleshooting guide shall look at all those issues. So, instead of calling an expert right away when your mini split won’t work, try to troubleshoot it.

In most cases, you don’t need an expert to get your mini split back working unless it’s a replacement or a complicated issue like a drain clog, frozen unit, or refrigerant leak.

Let’s get into the troubleshooting guide and tackle each of the issues.        

Daikin mini split troubleshooting

In a rush? Check below the eight issues likely to face Daikin mini splits and their recommended fixes.

Quick Daikin Mini Split Troubleshooting Guide

ProblemLikely CauseRecommended Fix
1.Mini Split Won’t Turn OnPower outage, failure to turn on the on/off switch, loose cord, tripped breaker, exploded fuse, non-responsive remote, or wrongly set timerConfirm there’s no outage, the on/off switch is on, and the AC is plugged in well. Reset the breaker if it’s off, replace the fuse if it lacks continuity, and change the remote batteries. Also, check the timer and adjust it accordingly
2.Daikin Mini Split Not Blowing Cold AirHigh thermostat setting, dirty filter, surrounding filth, open doors and windows, frozen coils, a faulty thermostat, or broken ventilation fan Lower the thermostat setting, clean dirty filters, clear surrounding filth, and shut some doors or windows. Call an expert in case of frozen coils, low refrigerant, a faulty thermostat, or a broken ventilation fan
3.Mini Split Won’t DrainMold-blocked condensate line Call an expert to unblock the mold-obstructed drain
4.Mini Split Won’t DehumidifyMold-blocked condensate line or oversized unitCall an expert to unclog the condensate line, but if the unit is oversized, get a smaller alternative
5.Daikin Mini Split Not Blowing Hot Air  Low thermostat setting, dirty filter, furnace not tuned on, power failure, closed windows and doors, low refrigerant or faulty ventilation fan or compressorAdjust the thermostat setting, clean dirty filters, turn the furnace on if it’s off, and ensure the AC has power. Open some doors and windows if all are open, and call an expert in case of a low refrigerant, faulty fan, or compressor
6.Mini Split Won’t DefrostClogged filters or low refrigerantClean dirty filters and call an expert to address a low refrigerant
7.Mini Split Keeps Going OffDirty filters or low refrigerantClean the air filter if dirty and call an expert when it’s a refrigerant leak
8.Mini Split Leaks Clogged drain or filter, broken drain pipe, or wrong installationUnclog the condensate line and clean a dirty filter. Talk to an expert in case of a broken drain pipe or incorrect installation

8 Common Daikin Mini Split Troubleshooting Problems 

Below are eight air conditioner troubleshooting issues prevalent among Daikin mini split.

See also  Simple Guide: How to Replace a Ducted RV Air Conditioner

1.  Daikin Mini Split Not Turning On

Your Daikin mini split won’t work if it won’t turn on. So, you ought to find out why and its most likely one of these reasons:

  • Power outage – If there’s a power outage, the mini split won’t turn on when you press the on/off switch. So, check if that’s the case.
  • Failure to turn on the on/off switch – Check the on/off switch to ensure it’s turned on. If it’s not, the mini-split won’t turn on. 
  • Failure to properly plug in the AC (loose power plug) – If the AC is not properly plugged into the power, it won’t turn on. 
  • Tripped breaker – The breaker will likely trip off when an abrupt power surge occurs. Once it does so, your AC won’t turn on. 
  • Exploded fuse – An abrupt power surge could also blow up the thermal fuse to protect the mini split. You can confirm if that’s the case using a multimeter. The fuse is faulty if it lacks continuity.
  • Non-responsive remote – If the remote control is not working, it won’t turn the mini split on. So, you ought to check the batteries and replace them if they are dead.
  • Wrongly set timer – If the timer is improperly placed or malfunctioning, the mini-split won’t turn on. So, check it to ensure it is correctly set. 


While you cannot do anything about an outage, you can troubleshoot other issues. Once you confirm there’s no outage, ensure the mini split is plugged in firmly and the on/off switch is on. 

Reset the breaker if off/tripped and replace a blown up (one with no continuity) fuse. If the remote is unresponsive, replace the batteries and adjust the timer correctly if it’s not set well. 

Daikin mini split troubleshooting codes

2. Daikin Mini Split Not Cooling

While cooling is arguably the mini split’s most crucial function, sometimes the unit won’t blow cold air. Overall, here are the likely explanations for a Daikin mini split not cooling enough:

  • High thermostat setting – The mini split won’t cool if your thermostat reading is higher than your room temperature. You won’t even realize it.
  • Dirty filter – A dirty filter prevents proper airflow. So, the cold air won’t go out of the AC unit. The room will instead remain hot. 
  • Surrounding filth – If too much debris or dirt heaps around your outdoor unit, especially the condenser, your mini split won’t cool. 
  • Open doors and windows – If all the windows and doors are open, the indoors will get excessively cold, which may prevent the mini split from cooling. 
  • Frozen coils – If the condenser or evaporator coils are icy, they won’t allow cold air to blow over them, so the mini split won’t cool.
  • Low refrigerant – The refrigerant /coolant absorbs heated air from your room to encourage a cooler surrounding. However, issues such as vibration and knocks could cause leakage and prevent cooling.
  • Faulty thermostat – if the thermostat is not working or malfunctioning, the mini split won’t be able to cool your space.
  • Faulty ventilation fan – If the fan is broken or obstructed, it won’t blow cold air, and the mini split will fail to cool.
See also  Unveiling What Causes Pipes to Freeze on an Air Conditioner


For the best cooling performance, the thermostat should be set at least 24 degrees lower than the room’s temperature. So, ensure that’s the case.

As for the air filter, clean them. Daikin recommends doing it twice a month in the summer and once in 6 months in other seasons. 

You can use tepid water and soap. Close some of the windows and doors if all are open. But if the issue is a frozen coil, low refrigerant, or faulty thermostat or ventilation fan, call an expert.

3. Daikin Mini Split Not Draining

If your Daikin mini split won’t drain or is probably dripping, the most likely reason is mold clogging in the condensate line. The clog is not only blocking the condensed water from draining but also causing backups and dripping. 


Unclogging a mold-obstructed line is not easy. So, it’s recommendable to call an HVAC expert. 

4. Daikin Mini Split Not Dehumidifying

You expect your Daikin mini split to blow cold air during the summer and take out the humid air. However, the AC may sometimes fail to do the latter, and if so, the reason could be:

  • Mold obstruction in the condensate line
  • The mini split is too big for the space (oversized)


Consider talking to an HVAC pro to inspect the condensate drain line and unclog it. But if the condensate line is not moldy, the mini split might be too big for your space. If so, you’ll need to undersize it (get a smaller unit).

5. Daikin Mini Split Not Heating

Your mini-split should be able to heat up during the frosty winter. If it’s not doing so, the reason could be any of the following:

  • Low thermostat setting – For the mini split to blow hot air, its thermostat setting should be higher than the room temperature.
  • Dirty filter – If the filter is dirty, the mini split won’t just fail to blow cold air but hot air too. 
  • Furnace not turned on – Your Daikin mini split won’t heat up if the furnace is off. So, you have to confirm that it’s turned on. 
  • Power failure – If there’s a power failure, your AC won’t turn on. So, you have to check the operation lamp to ensure it’s on. 
  • Closed windows/doors – If all the windows and doors are locked, the rooms will get hotter, making it hard for the AC to heat. 
  • Low refrigerant – A low refrigerant will not just discourage cooling but heating too. So, look for any signs of a refrigerant leak.
  • Faulty ventilation fan – A defective fan cannot blow cold and hot air. So, you’ve to check it to ensure it’s not broken.
  • Faulty compressor – The compressor can also prevent the mini split from heating up if it’s defective. You’ll need an expert’s help to check and fix it. 
See also  Amana Air Conditioner Not Cooling (7 Issues Fixed!)


Adjust the thermostat setting to promote heating and clean the air filters if they are dirty. Meanwhile, ensure the furnace is on, and the AC has power. If not, talk to an expert.

Consider opening some closed windows and doors and leaving the rest (low refrigerant or faulty ventilation fan or compressor) to an expert.

Daikin mini split not working

6. Daikin Mini Split Not Defrosting

If your Daikin mini split won’t defrost, it’s likely because of a clogged air filter or a low refrigerant. So, you should quickly check the air filter from clogging and watch out for any signs of refrigerant leakage, such as wetness and strange smell. 


Clean the air filters if they are dirty but leave the other issue (refrigerant leakage to an expert.

7. Daikin Mini Split Keeps Going Off

Your mini-split won’t stay on because of a dirty filter or low refrigerant. Remember, these are the same issues preventing the unit from defrosting. So, check the air filter for clogging and note any signs of refrigerant leakage, 


Clean the air filter if they are dirty and call an expert when the refrigerant is leaky.

8. Daikin Mini Split Not Working But Leaking

Several issues could result in a leaky mini-split. They include the following:

  • Clogged condensate line
  • Clogged filter
  • Broken drain pipe 
  • Wrong installation


Of all the four issues, the easiest to fix is a clogged filter which you’ll need to clean. Call an expert, however, to fix the rest. 

Daikin Mini Split Troubleshooting Codes

The Daikin mini split displays an error code when something is wrong. So, your job is to identify the fault code, interpret it, and take action.

Below is an error code/fault troubleshooting guide you can use.

Error CodeInterpretation What to Do
U0Low refrigerant Check the refrigerant and call an expert in case of a leakage
U4Wiring issueCheck the wiring for fault
A3Clogged condensate drainCheck the condensate line for mold blockage and unclog it
A5Frozen/ overheated coils Have an expert inspect the coils
A6Faulty motorReplace the fan motor
Flashing Green LightFilthy dust boxClean the dust box
Flashing Orange LightDirty streamer unitClean the streamer unit

Visit Daikin’s error code page to discover more errors and their meanings.

Daikin Mini Split Reset

Whether your mini split has an error code you want to clear, or the AC won’t start after an outage, it’s advisable to reset it, and there are two ways to do it:

Option 1 – Breaker Reset

This reset requires you first to turn off the mini-split and then flip off the circuit breaker. Wait 1 –2 minutes to flip the breaker and turn the mini-split on. 

Option 2 – Reset Button

Consider pressing the reset button on your indoor or outdoor Daikin mini split unit to rest the air conditioner. You may, however, have to wait for up to 30 minutes to see if there are any error codes. 

Closing Thought

Above is a Daikin mini split troubleshooting guide for your non-working air conditioning unit. Consider trying the DIY tips and leave detailed fixes and replacements to an expert.

As shared, most issues are DIY troubleshootable, so you shouldn’t be in a hurry to call an HVAC expert.