14 Fujitsu Mini Splits Problems & Troubleshooting Guide

Fujitsu is one of the best mini-split brands on the market. Their products range from entry-level to premium-grade, so almost any homeowner can find a unit that will beat the heat and cold in their homes. Unfortunately, even an excellent product has some problems, and Fujitsu mini-splits are no exception.

Here are the 14 common Fujitsu Mini Splits problems:

1. Fujitsu Mini-Split not Cooling

If your Fujitsu mini-split is not blowing cold air, then be assured that your mini-split has a refrigerant leak.

Technically, your heat pump unit needs the refrigerant to move heat and at the same time keep your home cold, so if your ductless mini-split is not blowing cold air, then the refrigerant could be leaking.

Solution: If your AC system has a refrigerant leak, you will have to replace them with new ones. You could call in an HVAC guy to help you do the replacement.

2. Fujitsu Mini Split not Heating

Consider checking out the coils to your mini-split, and if you see any frozen coils, then that is the reason why your AC unit is not blowing hot air to your room. Frozen coils result from ice forming around these coils due to the accumulation of dirt around the coils, making your AC unit generate hot air.

Another reason causing the frozen coils is the insufficient refrigerant level in your unit.

Solution: To solve this, consider turning off your unit by disconnecting it at the power source and allowing the build-up ice to melt. You could also try removing the ice using a dry cloth. When wiping down, be sure to remove all the moisture from the AC unit before reconnecting the power source.

3. Fujitsu Mini-Split Leaking Water

A dirty air filter will always cause your mini-split to leak water. Dirt and dust usually build up in the indoor unit, thus reducing the airflow throughout the AC unit, causing the coils to freeze up.

So when the coils warm-up, the ice, and frost undoubtedly melt and drip down onto your floor or wall.

Solution: To stop or avoid dripping water, always ensure to remove ducts and dirt from the air filters occasionally. Per your Ac system guidelines, you could also prevent leakage by changing your mini-splits air filters.

4. Mini Split Compressor not Turning On

The compressor to your mini-split is not turning on? First and foremost, consider checking the power source and making sure it’s powered on as this could be why the compressor is not turning on. 

If the power source is switched on, the compressor not turning on could be due to dirty coils and air filters, a dead compressor and capacitor, and starter relay problems.

Solution: Be sure to clean your air filters and coils as frequently as possible. Issues with a dead compressor can only be solved by purchasing another compressor. In cases where you suspect an electrical problem is causing the issue, then be sure to call an electrician to look at the power source.

5. Mini Split has Power But Won’t Turn On

Your mini-split system could not be turned on due to several reasons. An operational error will undoubtedly cause the AC system not to turn on for starters. Another reason that seems so obvious but could be the reason behind the unit not turning on is the power source being off.

Solution: Check your power source, has the fuse blown out? If so, then you will have to replace it. If it is an operational error, then be sure to contact a licensed HVAC technician to sort out the issue.

6. Fujitsu Mini Split Smells Musty

A musty smell is the same for just about any mini-split air conditioner, which makes the indoor air quality in your home feel damp. A musty smell means that there is the presence of mold or mildew growing in your AC unit.

Apart from a musty smell, some of the most usual smells are sour and fishy. The ductless mini-split smells usually originate in areas such as the condensate drain line, evaporator coils, and the drip pan, which are vulnerable to the growth of bacteria.

Solution: Consider contacting an HVAC guy to help you with professional cleaning. The mold issue needs to be done as soon as possible, or else this could take more than one cleaning to clear the mold or mildew.

7. Mini Split Never Shuts Off

It’s pretty natural to worry about wasting electrical power whenever you are not using your AC unit, and it’s not shutting off.

Several malfunctioning components could be blamed for this issue, such as clogged air filters, frozen evaporator coils, low fan speed, a bad circuit board or malfunctioning sensors, dirty condenser coils, low refrigerant levels, or a bad thermostat.

Solution: Adjust your thermostat temperature settings, clean up your air filters and condenser coils, and replace the bad circuit board.

8. Mini Split Freezing Up

Your AC system having low refrigerant will result in your ductless mini-split freezing up. The lack of refrigerant will cause the mini-split to force your unit to work harder to create cold air.

Solution: You will need to add additional refrigerants to eradicate the low refrigerant issue. 

9. Mini Split Making Noise

This is a problem caused due to plastic housing expanding while the system is on. This usually happens when the mini-split turns on defrost mode to keep itself from freezing over. If your mini-split turns to defrost mode, be sure that something is off with your unit.

 Making noise mini-splits tend to be annoying, and some of the sounds to watch out for are popping, gurgling, cracking, or clicking sounds.

Solution: You can try stopping the noise by opening the outside unit and checking the AC compressor first to make sure everything is okay, and be sure to contact an HVAC guy who can provide quality workmanship.

10. Mini Split Short Cycling

If your mini-split switches on and then switch off after a few seconds, it could be due to a refrigerant leak, electrical issues, air handler failure, or a reversing valve breakdown.

Solution: At times all your unit needs is to be restarted, so be sure to do so, and if this does not help, an HVAC technician could come to your rescue.

11. Doesn’t Operate Immediately

If you rapidly stop your mini-split and then immediately start it again, then the compressor will not function for about three minutes or so, causing your unit not to operate.

Solution: If you stop your AC unit from functioning for whatever reasons that you may have, always make sure to wait a few minutes longer before starting it up once more.

12. Airflow is Weak or Stops

If the fan speed is deficient, it will increase slower the rate to which the unit’s internal parts will receive hot air and warm-up, thus weak airflow.

Also, if the room temp rises above the thermostat setting, then the outdoor unit will stop, and the indoor unit will operate at a low fan speed.

Solution: Be sure to put the fan speed higher to get better the heat spread around your home.

13. Doesn’t Operate at All

This could result from power failure, a blown-out fuse, or a tripped circuit breaker.

Solution: Try checking your power source first and if everything is perfect, be sure to call an HVAC technician

14. The Unit Operates Differently from the Remote Control Units’ Setting

This could result from worn-out batteries, and if that’s not the case, the batteries may have been loaded incorrectly.

Solution: Check whether the batteries are correctly loaded and if that is not the problem, then be sure to purchase new batteries to solve the problem.

How Does Fujitsu Mini-Splits Work?

Usually, Fujistu mini-split works by allowing you to regulate the temperatures in your home. So if the weather outside is cold, you can warm up your home and vice versa.

A mini-split air conditioner has two main components: an outdoor unit/ compressor and an indoor unit/ evaporator. These facilitate the heating and cooling of your house.

Are Fujitsu Mini-Splits Reliable?

Pretty much reliable.

They offer up to 30% more efficiency and offer the longest life expectancy. They provide energy-efficient solutions to make comfort more affordable for utility bills. 

They are also suitable for those with allergies as they use static electricity to pull pollutants from the air; excellent, right?

Fujitsu Mini Split Error Code

Below are some of the standard mini-split error codes.

E1- Indoor/ Outdoor Unit Communication – This type of error code implies that the communication between the mini-split’s indoor and outdoor units has been impeded. Your unit could be experiencing connection issues. It could also indicate that your AC unit is experiencing high pressure.

E3- A Leak In the System – When this error shows up, a leak or any other restriction is causing the problem, especially when the air filters, drain line, and fan are dirty.

E5- Voltage Protection – This error indicates a problem with the system’s voltage, and this could be either low or high voltage.

E6- Indoor/ Outdoor Unit Communication – This is a communication problem between the indoor and outdoor units and is similar to the E1 code.

E7- Indoor and Outdoor Units Set to Different Modes – If one unit’s mode is set to generate hot air and the other is set to generating cold air, then your indoor display will show the E7 error code.

P4- Compressor Drive Error/ High Temperatures – This error code will appear if your compressor drive is not working as expected, caused by high temperatures.

P6- Compressor Switch Open – Your mini-split has computer boards that ensure both the indoor and outdoor units communicate. So the P6 error code appears when the compressor drive is faulty.

If the compressor switch is open, when the temperatures rise above levels, the safety switch will not protect the electrical components of your mini-split system.

H1- Defrost Mode – The error code indicates that the unit has entered defrost mode, and it occurs when the control sensor of the outdoor heat exchanger activates and switches off heat injection to the indoor unit.

H5- Power Module In Protection Mode – The protection mode controls over-voltage issues and under-voltage issues. It also regulates short circuit issues and over-temperature. So when this error appears, the power module has entered protection mode.

C5- Jumper Issues -This code indicates that the indoor board needs to be replaced and the jumper moved from the old board to the new one.

Fujitsu Mini Splits Problems FAQs

Why is My Fujitsu Aircon not Working?

Your mini-split could not be working because;

  • Your unit is not switched on
  • Bad circuit breaker
  • Clogged air filters
  • Dirty condensate drain line
  • Ice build-up
  • Wrong settings
  • Compressor not wearing out

How do you Reset a Fujitsu Split System?

You could reset your AC unit by switching off the main power and letting it power down for at least ten minutes, then restart it. If the AC unit is switched on and the circuit breaker is intact, check the isolator at the outside unit and make sure it’s switched on.

Why is my Fujitsu Blinking?

If the mini-split blinks continuously, it could be a model error, which means the indoor and the outdoor unit are mismatched.

Why is my Fujitsu Heat Pump Light Flashing

If the heat pump unit is flashing, it’s in defrost mode. You could try waiting for about 30 minutes, and then it should start to heat again. If it does not, a mini-split repair needs to be done as soon as possible/

Where do I Find the Error Code on my Fujitsu Aircon?

The error codes are usually displayed on the remote control. To get the error codes, press the energy save and zone control buttons simultaneously for about 4 secs, and the error code will be displayed on the LCD.

How do you Reset a Fujitsu Heat Pump?

You can reset your heat pump by turning down your AC unit using the thermostat. Please search for the breaker box, which will be found in your basement or garage, and shut it off. Wait for a few minutes before turning the breaker on. Once you turn the breaker on, wait for about 30 minutes before turning the thermostat on.


There is nothing better than escaping the scorching heat of summer with the use of your mini-split unit. But when problems arise with your home comfort system, you no longer feel confident with your home.

So when these common problems arise, be sure to book an appointment today with one of the best HVAC technicians. These technicians will offer you quality workmanship at fair prices and be ready to provide support for all your HVAC needs.