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Mini Split Not Heating or Cooling? The Complete Mini Split Troubleshooting Guide

mini split troubleshooting guide

Mini splits are highly efficient AC systems that provide both cooling and heating, while being able to service multiple zones. But like any AC system, mini splits can suffer their fair share of troubles and issues with time.

In this detailed guide, we’ll help you troubleshoot your troublesome mini split, whether it’s heating, cooling, or other issues that need to be fixed. We’ll also identify scenarios where it may be necessary to get a professional technician to fix the problem.

Common Mini Split Problem #1: Mini Split not Heating or Cooling

One of the most frequent complaints with mini split systems is inadequate cooling or heating. This can be caused by several factors, including:

Improper Sizing: If the mini split system is not sized correctly for the space it’s intended to cool or heat, it may struggle to maintain comfortable temperatures.

Dirty Air Filters: Clogged or dirty air filters restrict airflow, reducing the system’s efficiency and capacity to heat or cool effectively.

Refrigerant Leakage: Low refrigerant levels due to leaks can impair the system’s ability to transfer heat, resulting in insufficient cooling or heating.


  • Check the size of the room and compare it to the capacity of the mini split system to ensure proper sizing.
  • Inspect the air filters and replace them if they are dirty or clogged.
  • Conduct a thorough inspection of the refrigerant lines and connections for any signs of leakage, such as oil stains or hissing sounds.


✓ If the system is undersized for the space, consider upgrading to a mini split system with higher capacity or supplementing it with additional units for larger rooms. Here’s our practical guide to mini split sizing.

Regularly clean or replace air filters according to the manufacturer’s recommendations to maintain optimal airflow. Depending on how long it has been since the filters were cleaned, coil cleaning may also be necessary. 

✓ If a refrigerant leak is detected, contact a qualified HVAC technician to locate and repair the leak before recharging the system with the appropriate refrigerant.

Common Mini Split Problem #2: Unusual Noises

Unusual noises emanating from a mini split system can be disruptive and indicate underlying issues that need attention. Common sources of noise include:

Loose Components: Vibrations or loose parts within the indoor or outdoor units can produce rattling or banging noises.

Fan Issues: Faulty or dirty fan blades may create squealing, scraping, or clicking sounds during operation.

Refrigerant Flow Problems: Air bubbles or obstructions in the refrigerant lines can cause gurgling or bubbling noises.


  • Inspect the indoor and outdoor units for any loose or improperly secured components.
  • Examine the fan blades for signs of damage or debris accumulation.
  • Listen for unusual sounds emanating from the refrigerant lines during operation.


✓ Tighten or secure any loose components within the unit to reduce vibrations and eliminate rattling noises.Sometimes the filters or front cover can be out of place and rattle. Be sure everything is snapped in properly. 

✓ Clean the fan blades thoroughly to remove dirt, debris, or obstructions that may be causing abnormal sounds.

✓ If refrigerant flow issues are suspected, contact a professional technician to inspect and address the problem, as working with refrigerants requires specialized knowledge and equipment.

Common Mini Split Problem #3: Electrical Malfunctions

Mini split systems rely on electrical components to operate efficiently, and issues with these components can lead to system failures or malfunctions. Common electrical problems include:

Power Supply Issues: Tripped circuit breakers, blown fuses, or faulty electrical connections can disrupt power supply to the mini split system.

Defective Controls: Faulty thermostats, control boards, or sensors can prevent the system from functioning properly or maintaining desired temperatures.

Wiring Problems: Loose or damaged wiring connections can cause intermittent electrical faults, communication issues, or complete system shutdowns.

Surges and Lightning Strikes: The electrical components of mini split systems are sensitive to fluctuations in electrical current.


  • Check the circuit breakers or fuses in the electrical panel to ensure they are not tripped or blown.
  • Test the thermostat and other control components for proper functionality using a multimeter or thermostat tester.
  • Inspect the wiring connections for signs of damage, corrosion, or loose connections.


✓ Reset tripped circuit breakers or replace blown fuses to restore power to the mini split system.

✓ Replace faulty controls or sensors as needed to regain proper system operation and temperature control.

✓ If wiring issues are identified, consult a professional electrician to repair or replace damaged wiring safely.

✓ If you have recently experienced a lightning storm or power surge, this may cause issues with the electrical boards in the indoor or outdoor unit. The unit may not function at all or you may get an error code on either the indoor or outdoor unit. If this is the case, consult an HVAC tech for help.

Check out our Mini Split Wiring Guide to help ensure you wire your system correctly.

Common Mini Split Problem #4: Refrigerant Leaks

Refrigerant leaks can significantly impact the performance and efficiency of a mini split system. Common causes of refrigerant leaks include:

Corrosion: Corrosion or damage to the refrigerant lines or connections can lead to leaks over time.

Poor Installation: Improper installation techniques or faulty flare connections during initial setup can result in refrigerant leaks.

Wear and Tear: Normal wear and tear on the system components can cause seals or joints to degrade, leading to leaks.


  • Inspect the refrigerant lines, connections, and components for any signs of oil stains, corrosion, or refrigerant leakage.
  • Use a refrigerant leak detector or soap solution to identify leaks in the system.
  • Measure the system’s refrigerant levels using pressure by evacuating the refrigerant and weighing it to determine if a leak is present.


✓ Repair or replace damaged refrigerant lines, connections, or components to prevent further leakage.Sometimes it may be necessary to cut off an old flare and reflare it for a better connection.

✓ Recharge the system with the appropriate refrigerant to restore optimal performance, ensuring proper pressure levels and system functionality. Refrigerant should always be weighed in to a mini split system.

✓ Keep in mind that newer mini split models may use A2L refrigerants, in place of the old R410-A that is being phased out.

Common Mini Split Problem #5: Drainage Issues

Mini split systems produce condensate as they cool or heat the indoor air, which must be properly drained to prevent moisture buildup and potential water damage. Common condensate drainage problems include:

Clogged Drain Line: Accumulated dirt, debris, or algae growth can obstruct the condensate drain line, causing water to back up into the system.

Improper Slope: Inadequate slope or improper installation of the condensate drain line can impede drainage and lead to water accumulation.

Frozen Evaporator Coil: A frozen evaporator coil can cause excess condensate production and drainage issues when the ice melts.

Failed Condensate Pump: If your system was relying on a condensate pump to move away water and it fails, you may notice leaking at the pump.


  • Inspect the condensate drain line for any clogs, blockages, or algae growth.
  • Verify that the condensate drain line is properly sloped to ensure efficient drainage.
  • Check the evaporator coil for signs of ice buildup or frost accumulation.


✓ Clear any obstructions from the condensate drain line using a vacuum, drain snake, or compressed air. A gallo gun can also be used.

✓ Adjust the slope of the condensate drain line as needed to facilitate proper drainage away from the unit.

✓ Thaw a frozen evaporator coil by turning off the system and allowing it to defrost naturally, then address any underlying issues contributing to the icing problem.

✓ If you are using a condensate pump and it has failed, check to make sure it is getting power and that any filter it may have is clean. If that does not resolve the issue, it may be best to replace the condensate pump

Common Mini Split Problem #6: Unresponsive Controls

There may be times when the mini split does not respond to commands, whether from a remote control or from the onboard display. Common causes of communication problems include:

Poor Signal: Caused by improper wiring.

Damaged Board or Compressor: Improper wiring can cause other system components to fail and require replacement.

Communication Error Codes: Error codes may be visible on the indoor unit or outdoor board.


  • When the mini split suffers inconsistent operation
  • Unit working in some modes, but not others
  • Outdoor unit powers up but indoor unit does not
  • Indoor unit has power, but will not operate


✓ Using the proper mini split communication wire is critical to a properly functioning unit. While some manuals may only call for 18 gauge wire it is always recommended to use 14 gauge 4 conductor wire (14/4) for most systems. Most local codes require 14 gauge wire, so using something smaller will not pass inspection in many areas. 

✓ The wire should be stranded, not solid core. Solid core wire has been known to cause more issues. Make sure that the wire is a direct run from the indoor unit to the outdoor unit without any junctions. 

✓ Make sure the wire you select is rated for indoor and outdoor use. 

✓ If you are installing a unit in a commercial application, an armored cable is usually required. 

As with anything, check your local electrical codes and consult an electrician to ensure proper installation.

Common Mini Split Problem #7: Improper Grounding

Grounding is important for any device that contains electronics. A mini split is no different. The control boards used in a modern mini split system are very much similar to a miniature computer. Proper grounding is therefore essential to the well-being of the control board, which can be affected by:

Power Surges: A spike in electrical power, such as after a blackout, can damage the board.

Stray Electrical Energy: These can come from environmental sources, such a lightning strike.

RF Interference: Many common household appliances and everyday electronics emit radio frequencies, which can cause interference with the RF band used by the control board.


  • Verify whether the compressor is grounded properly
  • Check the connections of the wiring


✓ When wiring the system, make sure the connections are correct. Most systems will have a terminal block with L1, L2 and C. L1 and L2 are your hot lines. C is your common or ground. 

✓ Grounding the chassis of the condenser to a ground rod also adds an extra level of protection. If you use a grounding rod, check it on occasion for deferrization.

If you are unsure about grounding, consult with an electrician.

Common Mini Split Problem #8: Cold Weather Operation

The temperature outside can impact a mini split’s performance. Not all mini splits are rated for extreme cold weather. Symptoms of poor performance include:

Mini Split Not Heating: The heat pump is unable to provide heating.

Unusual Noises: These indicate the unit is struggling to perform in extreme conditions.


✓ If your unit has an optional drain pan heater, adding this can increase the temperature range in which the unit will operate. 

✓ Make sure that if you are in a location that gets snow your unit is installed on a stand or wall mount that is above the snow. You should also remove any snow from the top of the unit before operating. Overly windy areas can also negatively impact the unit.

✓ If you are trying to use cooling at low temperatures for a server room or other environments that call for cooling all year long, make sure you purchase a unit that offers low ambient cooling

✓ Adding a wind baffle will expand the range of the unit.

When to Seek Professional Help

While some common problems with mini split systems can be diagnosed and resolved by homeowners, there are certain situations where professional intervention is recommended:

Refrigerant Handling: Handling refrigerants requires specialized training, licensing, and equipment to prevent injury or environmental damage. Always enlist the services of a qualified HVAC technician for refrigerant-related issues.

Electrical Repairs: Working with electrical components can be hazardous, especially for those without proper training or experience. Consult a licensed electrician or HVAC technician for electrical repairs or wiring issues.

Warranty Concerns: Attempting DIY repairs on a mini split system under warranty may void the warranty coverage. Always check the manufacturer’s warranty terms and conditions before performing any repairs yourself.

Troublesome Mini Split: Repair or Replace?

If you have just purchased a new unit and are experiencing any of the issues outlined here, call your installer immediately to get them sorted out. If you are having trouble with an older mini split, it may be time for a new one. Replacing boards or compressors on older systems can be expensive and time consuming.

Friedrich and Daikin are the leaders when it comes to reliable, long lasting mini split units. Exceptional build quality and commercial grade components are backed by industry leading warranties. Let our experts help you choose the best new mini split for your application.

Multi zone mini split buying guide

Mickey Luongo

Mickey is the resident heating and air conditioning expert with over 15 years of experience in the industry.

94 thoughts on “Mini Split Not Heating or Cooling? The Complete Mini Split Troubleshooting Guide”

  1. Replaced both capacitors and mother board in condenser …split ac unit w/one head unit inside. Still getting blinking red light and pulsating/flickering green light. Condernser will not come on…head unit opens and closes flap, but no fan!
    Thanks, Harry

    1. Hi, Our older unit (Mitsubichi mini split) suddenly will not heat. Everything else works well, fan cooler, dehumidifier but when we set it to heat, it turns off.

  2. Chuck Purce says:

    During the heating mode, Is it normal for the condenser on the unit to have accumulated frost all around the exposed condenser? The weather overnight was in the 20’s.

    1. Mickey Luongo says:

      Depending on the unit, this is possible. Some mini splits, especially older ones do not perform well in cold temperatures. If available for your unit, you may want to add a drain pan heater or wind baffle.

    2. Not! Most likely low on refrigerant. Call a expert hvac co. Dont rely on the flunkies, plenty of them out there..🤔

  3. Our mini splits Turboair TAS-09VH. Everything work except heat. Would you advice ? I have 3 of this identical machines. Can I swap part to troubleshoot ?

  4. I just had a 18000 and a 9000 split Comfortstar unit installed in my new addition and the units in heat mode continually go into df mode. This is a constant issue after 1 week of worryfree use. Both units do this. I have had the installer here 5 times and the last time he replaced the exchanger unit outside. To no avail, the problem still exists. Anyone with a reasonable explanation will be greatly appreciated. My addition is cold and i need this problem fixed

    1. Mickey Luongo says:

      Depending on where you are located and how cold it has been, you may be reaching the lower limits of the system’s heating capabilities. Also, the system probably needs a drain pan heater installed.

  5. Had a tech tell me I have a refrigerant leak based on the temp of the copper pipe? Is that a reliable way to troubleshoot? Said it should be 90-100 degrees higher than ambiant temp which sounds high for a mini split.

  6. I have a multi zone with 5 units 3 in the second floor (9000 + 9000 and 6000) and two in the first floor (15000 and 9000) , 4 of them work perfectly but the one of 15000 has always two lights on, like still working to reach the set temperature. Why??

    1. BTW, the unit of 15000 is in the dinning room that connect to kitchen and Living room. My question if is normal for a unit who feed 3 rooms to have the two lights ON all the time even if I lower the temperature.
      The other 4 units just turned ON the second light just during the time is trying to reach the temperature and go back to one light.

  7. Hi, we have two 4 unit panasonic systems in our home. All except one work fine. This one doesn’t seem to put out much air, and makes a continuous annoying noise. It seems that it always has done it. Could it be the wiring? Reading through the article that makes the most sense. Past warranty and refuse to return to original company we purchased from. THANKS!

  8. Ellen Smith says:

    Our Fujitsu mini-split is about 4 years old. It keeps failing to function & showing flashing lights. We have had our HVAC guy out about 10 times, but most of the time we have to turn it off, bang on the outside door and restart it. The unit is high up & no one is touching it. This is really annoying because room temp goes low and our plants are dying. Should we call another HVAC guy, get a new unit or just keep the ladder out and bang on it periodically? Thanks so much

  9. David Roback says:

    The mini split works, it heats and cools but the front door with not rise when the unit is turned on. The cogged wheel does not seem to be broken or chipped on the right rear side of the door. Any other ideas?

  10. I have a mitshubishi split air conditioner with two returns. One develops a brownish oily residue on the airflow blades. What could be causes this to occur? Other than that, it works just fine.
    I routinely clean filters and coils are clean.
    Mitsubishi customer service was of no help. I was told to contact my installer.
    I’m also looking for a part for the outside unit to stop a slow drip. One doesn’t seem to exist.
    Thanks for any help.

  11. Barbara Porter says:

    my son has a quad split ductless unit in his home in hawaii. the units in two of the bedrooms are not working the tech that the property manager had look at it says that one board is bad but they would have to replace all 4 at a cost of around $14,000. is this right or is someone trying to con him into spending more than he needs to?

    1. Mickey Luongo says:

      That doesn’t sound right. I would recommend getting a second opinion from another professional.

  12. Nancy Halstead says:

    my Fujitsu mini split is flashing slowly in the operation and timer lights and the economy light is flashing rapidly. I tried tiring it off and on as well as reset the circuit breaker but the unit is still not working and all the lights are still flashing. how do i fix this?

    1. Mickey Luongo says:

      I would recommend finding the service manual for your model. That will tell you what the blinking lights means and what the issue with the unit is.

  13. I have a mini split that the high side line is sweating. A tech once told me if that line is sweating it’s likely the system needs a charge. We put our gauges on and it’s spot on. What else can I look for, the lines sweating in an attic area and dripping through. Any help appreciated

  14. Marissa Binstock says:

    My unit is showing d1 and not cooling at all. I can’t find this error code any where online or in the manuals. Anyone have any idea? Thanks!

  15. My two year old LG inverter v has had two pumps to the attic replaced. They are meant to draw the water from the dehumidifier up two feet to the outside drain. Why do they fail. Northeast of Albany, MY said this is an aftermarket part not warrenteed

    1. Mickey Luongo says:

      It sounds like you are talking about condensate removal pumps. I would ask your installer what kind they are using and consider switching to a more reliable brand like Sauermann or Refco. Those do have warranties.

  16. I just had a new bryant mini split installed, I have the temp set at 72 but when i wake up in the morning it will be 65~ in the room. Is this normal? The installer told me it would shut off just like and AC when the set temp is reached.

    1. Mickey Luongo says:

      It sounds like there may be an issue with one of the thermistors on your unit. I would ask you installer to check it out.

  17. Steve johnson says:

    My wall mount unit leaks onto the floor there is a condensate pump does the line leaving the unit have to have fall to the pump?

  18. On newly installed Carrier Split system only a couple of weeks old there is a harsh chemical smell ,sorta like melted plastic aroma that ruins the air in the room. This only happens during cooling , not heating. Not sure what causes it to happen. Only happens intermittently and then the air is fresh again. It is enough to make you open all the windows and air the room out till the next time it does it. That smell is never in the room if AC is not used. Any ideas on how to solve this issue would be appreciated. I don’t think the unit has had time to grow anything yet in the coils, could it be wiring / insulation / windings on a motor or other component getting hot but only during one of the cycles … ? Is that the Odor of the Freon leaking out ( intermittently ? )

  19. I have a ComfortStar mini split 12,000 BTU. The indoor unit was just cleaned since the technician (who is unfamiliar with this brand) thought the problem was because it needed to be cleaned. The unit cools but the blower is barely blowing, certainly not as it use to. Any idea what the problem may be? Thank you.

  20. Anthony Gurrola He. says:

    Hi Diane. It sounds like the Phillips screw that mounts the blower wheel to the motor shaft may need to be tightened down a little more.

  21. Rob Frantz says:

    Just installed a comfort star mini split. After days it quick cooling. I’m guessing there must be a leak, but any other thing it could possibly be?

  22. Diane M says:

    We had a fujitsu mini split installed last August. 3 times now, have had a non cooling issue. We’re told there was a leak, and now, same issue. Compressor doesn’t come on . At a loss. Not even 1 year old.

  23. Simon Page says:

    I have a Daikin Mini Split and generally it works fantastic. I have noticed that when using the AC it seems to act like it is in AUTO mode. During the heat of the day, the AC is on and seems to be working correctly in cool mode (snowflake), however occasionally I open the windows when it cools off outside and I find it on in the morning and putting out heat when the temperature is cooler than the set point. Both of the head units are set the same way, so I don’t think its a conflict between them.

  24. Dan Buckley says:

    I have a Fujitsi mini-spit on my first floor. 1- 18,000 BTU indoor head in Living room, 2-9000 BTU heads in dining room and kitchen.

    The 18,000 unit seems to be lacking in production in AC mode. One of the 9000 units, which is placed on an opposite side wall seems to produce all the cold air. So much that I have placed this 9000 unit on fan ONLY mode and it still kicks out more cold than the 18,000 unit.

    Any reason why this may be happening?

    1. Mickey Luongo says:

      The first thing I would recommend it checking for a leak in the system as it is the larger units that are affected first.

  25. Jonathan D Pryor says:

    Have my LG Prestidge in AC mode and noticed that the fan seems to be running in low setting despite fact I set it to high. Why would this be?

  26. I purchase a carrier unit about 15 years ago . now the unit only comes on with the on and off button on the unit. Is it the remote and where could i get a similar one from> I look on line and can not find one

  27. David Walker says:

    My ductless mini split outside unit condenser coil started leaking refrigerant. How does this happen?

  28. I’ve had a dual system mini split for five years that has worked fine. Lately they only work if they are both running and do not cool when they’re running separately. I can’t find any information on this I need help

  29. Ron Sturdy says:

    My Friedrich mr12y1e stopped cooling overnight. Indoor evap seems OK. Blowing room air temp. Outdoor unit fan works and runs continuously but compressor won’t start. Dual cap 5/50 370. I don’t have a way to check cap. I can’t belive the compressor went overnight.
    While I’m a not a hvac guy I was a journeyman machine maintenance/machinist. I have repaired many units over the years. Most of the time its the run cap or the evap fan. I downloaded the manual and searched online. I hate to replace the cap if some other failure is more likely. Any thoughts?

    1. Mickey Luongo says:

      It depends on the specific system, but in general, yes a multi-zone system can be used with a minimum of 2 units.

  30. We have a compressor serving three indoor units. All the indoor units are showing the condensate image and not turning on. Any suggestions?

  31. The unit is a Seville and it cools fine but when you turn the heat on it goes to defrost mode and run and shows a code of PO And P4 the outdoor unit fan will come on when the codes appear and runs slow and then will kick off after about five seconds can you help with the problem

  32. My Willis air temp shows an H5 error. Can anyone tell me what this might be and a way to fix it. The unit is less than a year old but Canadians weather means we need heat.

  33. lynn althouse says:

    Our split unit is running pretty much all the time. It is set for heat. It will run and heat then runs cool. Doesn’t shut off when temp is met

  34. I had my fujitsu mini-split installed less than 6 months ago. It has 2 wall mounted units – the smalled unit runs perfectly fine & never had an issue. The larger unit was incorrectly installed which resulted in the unit leaking inside the house. It was “fixed”, developed a leak again, was “fixed”, developed another leak. A new technician came & reinstalled the entire unit & it worked great – until it started leaking again…this time the issue was that the line out was too long & got stuck in mud & the water built back up into the unit & leaked again in the house. The same technician who re-installed everything came to fix it again & it’s worked great…until this morning…we are now in heat mode & have been in heat mode for over a month – but today the wall was wet again….I checked to see if the line was backed up or anything like that – but don’t see anything.
    I recently changed the filters – is there anything in my filter changing that would cause water to appear on the walls?
    Has anyone experienced water on the walls when their unit was in heat mode?

    thanks in advance

  35. Frank Carroll says:

    My Daikin mini split will not heat. The cooling seems to work fine, but when I shift the mode to heat, the outside unit stops running and the inside fan doesn’t blow. The louvres continue to swing, but no heat.

  36. Mitchell Anderson says:

    Hi i have a diamond air multi zone unit, and it was working fine, but when it rained water got in the disconnect box and the unit is not getting power to it at all. I changed the disconnect box and there is still no power to the unit. Its getting power to the disconnect box but no power to the unit. Please can u help me?

    1. Call a qualified electrician, or someone who has a very good expertise with electrical connections.
      Could be an open in a wired connection.
      Continuity check required. Or a ground that was broken or damaged from previous problem. Or a short that burned something out.
      Fairly difficult to diagnose over the internet. Good luck.

  37. Jolene Scott says:

    We have a 2 year old Fujitsu Halcyon mini split running a ceiling cartridge downstairs and two smaller wall units in the upstairs bedrooms. A few weeks ago I came home to a cold house. The breakers for the unit were tripped. I reset them and still no power even to the thermostat. HVAC installer (via phone call with Fujitsu service techs) diagnosed fried circuit board, also the outdoor fuse was fried, Three new boards installed. This got power to the units, but fan speed was very weak at highest setting barely noticeable that air was coming out at all, the unit was set to the swing function but that function never engages, and air never warmed up with the thermostat set to 88 degrees, HVAC installer back, drained and weighed refrigerant (it was a couple lbs low). They pressurized the system but could not find a leak. Replaced refrigerant and asked that we leave system on overnight in hopes it would throw a code, Today HVAC installer back. The breakers were tripped again as well as the fuse blown. After replacing fuse and resetting breakers the compressor is now toast too. No error codes, ever. The service techs are really not very nice either. Of course, the warranty does not cover labor, so the HVAC installer is not happy to be spending so many hours (16 or so now) diagnosing over the phone with Fujitsu. No offer to have a Fujitsu certified tech come to see what’s going on. This is way over the abilities of the HVAC contractor. There is no indication that there was ever any type of power surge. What can it be? I think we need a whole new outside unit.

    1. Sounds very much like the units were not wired properly. Poor wiring can cause many problems. Example: 14/4 wire should always be used, but it not required! Double grounding should have been done, most likely was not.
      Suggestion get an expert electrician to hook up all wiring! Don’t rely on hvac flunkies to do it right. (In my opinion)🤔

  38. I have a AUX mini split unit that heats fine but then the set temperature light starts flashing & the unit stops working. I can unplug the unit & replug it & it starts heating for a while & the same thing starts again Whats causing this to happen?

  39. There is a dripping sound that our mini split makes. I know when it’s cooling or heating, this is normal. There is no leak or anything. Just curious if there is a way to muffle the drip sound…
    Is it possible to put a rag or towel there where it drips to muffle it or would that create more problem than its worth? Suggestions?

    1. this requires more information. I know you probably have resolved it. I’m writing answers for people who might read this with similar problems. Check the drain line, check the indoor unit see if you can see any drips—if you are hearing it- its probably leaking so you really need to find the source of this noise.

  40. Hi

    We have a few month old 9000 BTU Comfort Aire unit installed in our bedroom. Our contractor moved the location of the outdoor unit after it was installed and caused an issue with the refrigerant which then had to be refilled. After that the unit functioned correctly again for the last month up until the last few days. Now, nothing happens when we turn on the heat. When I turn on the AC, cool air does come out but I am unsure if that’s just the cool air from outside or if the unit is actually working. Any thoughts on what might be the issue?

    1. Mickey Luongo says:

      Sounds like a slow refrigerant leak. I would have the installer check the system again and verify all connections.

    2. Sounds like you have a refrigerant leak. Don’t run the unit. Call a hvac co. With excellent references to properly diagnose the problem. It’s fairly hard to find a reliable source. There are more flunkies than good ones. Good luck.

  41. Anton Koprivnik says:

    My pioneer 24,000 ducted mini split is up and running. We are in the middle of winter and the unit is heating well but does not seem to be controlling the tempeture. Thermostat is set at 62 but the unit will heat up to 74 room temp. Running on auto mode and heat mode. Same results. Remote unit temp selected matches inside manual unit. Is this a thermostat problem or inside unit control board failure? There are no error codes.

  42. I have a lg mini split system with three different zones. The two 9000 btu
    Units work fine but the 24000 btu unit does not heat the way it should.
    It runs fine for about 10 minutes then goes into preheat mode for 10 minutes and runs fine again. No matter what the thermostat is set at it
    Always goes into preheat mode 4 degrees before it reaches set temp.
    Is my problem with the thermostat or the unit itself . If unit is set on
    jet mode it runs perfect for the 30 minute set time. Any info will help
    as repair techs cannot figure it out .

  43. Wanson Hemphill says:

    My Fujitsu heat pump is working good except the door won’t rise up. I cleaned the screens and the cogs look fine.
    How do you set the cogs on the door before closing?

  44. Hi Mickey
    Just install ypthe Pioneer mini split. Model WYS012AMFI17RL. Instal went well no issues. However when I went to test and try the system the indoor unit doesnt work. I checked power from the fuse box to the line. Getting power. I checked power to the outdoor unit, yes getting power. I checke power at the indoor unit and no power. All the wires are tight and the red, black and white wires (1,2,3) are connsected to the same on the outdoor unit. I checked the wires directly at the indoor unit and not getipting power. What am I missing?

  45. I have a 18000 Panasonic mini split installed about a month ago that I cannot control the temperature on. Set to 20 and it will run until 25 and cut out. Set to 21 it runs to like 26 and cut out. Installer says this is normal and how the unit works but don’t make sense to me. Any ideas?

  46. Mini Split Cleaning & Maintenance - A How To Guide says:

    […] you maintain your mini split unit, other issues may occur. Some problems can be solved by basic troubleshooting, whereas others might require the help of a […]

  47. Is it ever a good idea to install the outdoor unit in a garage in Florida ? Two units in a 500 sq ft apartment but the things can’t keep the place cold. Also main unit is making all kinds of noises . I have to turn it off it’s so loud. The AC guy that installed it can’t seem to get the thing to work right . How do I get a Daikin rep out to review the installation and trouble shoot?

    1. Mickey Luongo says:

      Installing the units in a garage in Florida would not be a good idea unless it is open all the time. The outdoor units would add heat to the space and could cause them to lose efficiency and not perform well.

  48. I have a 24 mr cool mini split the unit will shut down when I turn the ac on I can hear the compressor kick in but before it starts to get cold the unit kicks off could it be the fan or condenser motor?

  49. Michael Kraintz says:

    Mitsubishi Model #PKFY_P24MFMUE installed 9 years ago. Unit has had no issues until recently it developed a squeaking noise when the fan turns on. I’ve been though the unit Cleaning filters, washed the coil and fan, sanitized fan. The squeak stopped but returned after a couple of hours. Tenant is not happy, please help.

  50. Debra Anders says:

    I messed up my husband is away and I opened the flap thinking that is where I turn on our new unit and now it will not close all the way. Could you please help me fix it. Thanks Deb

  51. Cat Smith says:

    Our pioneer unit has worked well, but the main 18000 unit in the main room has always had an air blowing sound when on. Now has gotten very annoying, we have had the unit for about 2 years now.

  52. Greetings, I have a 12k BTU Senville with the wall mount evaporator. I have been working with their support (who has been pretty good so far) to try and get it to put out cold air. It outputs around 15 degrees cooler than ambient (about 55 at the coolest) when on “turbo” mode. It used to get much, much cooler and it seems to heat as expected.
    I did have to replace an external board, and I’ve replaced the internal board at the advice of Senville support. The only thing we’ve not yet replaced are the temp sensors.
    I did pull a vacuum and filled it by weight (with the bottle upside-down to get the liquid vs just the gas), and added the few oz. for the 25′ line. All the coils are cleaned and I also went through and cleaned up the squirrel cage. Any other suggestions on what I should try? The tech support did say my low side was registering a little high, unfortunately, the Senvilles don’t have a high-side port.

  53. Candace says:

    I have a 5 year old Klimaire mini spit that runs on 12k btu.
    It is only blowing hot air. Any trouble shooting ideas I can try before I call a pro?

  54. Dan King says:

    I have a Daikin Mini Split that was installed a couple of years ago. It has intermittently continued to cool well past thermostat setting (i.e. Thermostat set at 72, cools down to low 60’s if not caught in time). I have my regular furnace set at 65 during the winter so it kicks on if the temp dips into the single digits disabling the split unit so we have heat (Unit is 12-130 degree range). This past April, while on vacation, it started cooling to the point the furnace kicked on and they essentially were fighting each other. We were gone for 10 days and we don’t know exactly how long this went on, but the next electric bill should tell. I have done a hard reset at the breaker and it still wants to cool down to 66/67 before I catch it and turn off the unit and back on again. This temporarily seems to work, but it seems to be becoming more regular. Any guesses?

  55. Kurt Kohler says:

    I have a 10 year old tri unit- cool only- LG. I only ever have had 2 inside units hooked up. These are both 12k. These power rooms on different floors. Recently the downstairs unit doesn’t cool but the upstairs works fine. I tried putting some more Freon in ( a professional did) and it worked for a couple days. The compressor comes on and shuts off a lot. Any ideas,? Thanks!

    1. Mickey Luongo says:

      It sounds like you have a leak. Adding more refrigerant is just a temporary solution. You will need to identify and fix the leak in the system.

  56. Michael Crook says:

    We have a Mitsubishi 2 head doubtless heat pump system. When in heating both work fine. When in cooling one head works fine, one head doesn’t cool well. In a half hour or so of cooling unit shuts off. If you only turn on the one head that head begins to ice up immediately. When you turn the larger head on by itself that head operates fine. Can the LEV work in heating mode but not in cooling. When in heating both heads work well.

  57. Les Neubauer says:

    I have a mini split air conditioner, both units work fine for about 5 minutes, then both shut off. Either unit will run on its own perfect, If I start the other unit with fist one running, they both work for about 5 minutes then both shut down. I need help

  58. Tonya Miller says:

    I have a Blueridge single zone mini-split. After a storm where we lost power, I noticed the unit will only work at high speed (no matter what I set it to). This happened about 6 months ago, and since it was very cool outside I left is off for a couple of months. It has happened again and it is very hot now so I can’t leave it off for long periods. What can I do to get that fan “Un-stuck”????

  59. Just instaled a 36000 mini split and the guy that did the final conections would not certify it not being one of his units. Well he forgot to open the main gass from the unit to the header. Started the unit and got p4 code and now it seams the compressoris jamed acording to manufacturor and needs replacing. As ennyone managed to unjam a compressor a litle trick of the trade or something. This hvac guy realy put me in a jam he wont even answer my calls

  60. Richard Geary says:

    I have a Diakin split system. 18,000 with 24,000 Heating. When using the Cooling it spit out small black specks of looks like dirt and it is real fine. I clean the filter as need and would like to know what is causing this. I put a unit in my Daughter house also and the same thing is happening. My until is about Five Years old and My daughters is about three years old. Can you help me. Thanks. Richard Geary

  61. Jennifer Schoff says:

    Hi, I have a Friedrich 24000 btu mini split ac heat pump. Both the inner and outer circuit boards have been replaced. The coolant level is right on the line between full and over full. I turn it on in the morning and E6 error code shows on inner unit, which is a communication error, the inner fan runs but compressor does not come on so no cooling. As temp increases outside to about 78 the compressor will come on and the inner unit works normally and the E6 is gone. As temps go down in the evening the compressor turns off and the E6 reappears. During cooling if it rains and the temp drops quickly outside the compressor turns off and E6 is back. The circuit boards were replaced after a chipmunk electrocuted himself on the outside terminal block. Cost $600 and the guy said this would fix the E6 problem, but it did not and no one seems to know what to do next. I know where the terminal blocks are outside and inside. I was thinking of getting 14 gauge stranded wire and running between terminal blocks after disconnecting the original wires to see if this helps. Any ideas what is going on?

  62. Hi Mickey,

    I have a daikin multi split system, 1 outdoor for 3 indoor units. 2 Indoor units are only blowing warm air but 1 is still cooling. I have had daikin technician come 2 times and he first said he needs to change the body expansion, that was changed and done nothing. Now he said needs to take unit to work shop for trouble shoot.

    Any ideas?


  63. Robert Cordell says:

    I have a ch 45 error on a lg mini split. This error seems to be a condenser pipe sensor error.

    The heatpump comes on for awhile and then goes off with the error. In a half hour or 2 hours , it will start working again.and then go off with the error. I have had 2 techs look at it but they can’t correct the problem.

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