Having mini-split installation done is a smart solution for solving comfort problems in your home. These systems don’t have to have ductwork to give energy-efficient heating and cooling. Much like any other home comfort system, they can have problems sometimes. Here are seven of the most common mini-split issues and how you can solve them. Show
1. Mini-Split is Dripping Water or Not Draining WaterIf your mini-split is dripping water or not draining water, there could be an issue with the condensate drain or drain line. It’s typical for a drain line to be clogged with mold, force water to back up and leak. Reach AZ Air Conditioning and Heating at 800-296-5088 for assistance and we’ll get your drain unblocked quickly. 2. Mini-Split is Making NoiseMini-splits normally don’t generate much noise when they’re operating. But there are two situations where they could make sounds.
You shouldn’t be worried if you hear these noises because they’re typical. However, if your mini-split keeps turning on defrost mode, it’s a hint that something is off, such as low refrigerant, a bad circuit board or malfunctioning sensors. Your AZ Air Conditioning and Heating HVAC tech will be able to locate and correct the problem rapidly. 3. Mini-Split is Not Heating or Blowing Hot AirIf your mini-split is not heating or blowing hot air, frozen coils could be the issue. Like we mentioned previously, frozen coils could be the effect of not enough refrigerant, a bad circuit board or broken sensors. Call us at 800-296-5088 for assistance. 4. Mini-Split is Not Cooling or Blowing Cold AirIf your mini-split is not cooling or blowing cold air, there may be a refrigerant leak. Your mini-split AC needs refrigerant to move heat and keep your residence cold. These leaks must be resolved by a licensed HVAC professional, so contact us at 800-296-5088 for support. 5. Mini-Split is Not DehumidifyingLike an air conditioner, a mini-split is effective at dehumidifying during the summer. However, this might be halted by mold in the condensate drain line. Another reason your mini-split air conditioner may not be dehumidifying very effectivelyis if it’s too large. A system that’s too large will cool down a space too quickly without having a moment to dehumidify it. Mini-split size is calculated on square footage and BTUs. 6. Mini-Split SmellsIf your ductless mini-split smells, it’s trying to get your attention that something is wrong. Here are five of the most typical smells and what they mean. Musty, Sour or MildewIf your mini-split smells musty, sour or like mildew, you may have a mold issue. Have a professional like AZ Air Conditioning and Heating inspect and clean the condensate drain and drain line, if needed. VinegarIf your mini-split smells like vinegar or has a sweet odor, you’re probably dealing with a refrigerant leak. Another surefire clue that you don’t have enough refrigerant is a lack of cold air. Reach us at 800-296-5088 for support. FishIf your mini-split smells like fish, a couple of things could be wrong. In some instances this smell means there is an electrical problem or that there’s a leak. Regardless, reach us at 800-296-5088 for support. 7. Mini-Split Will Not Power OnIf your mini-split will not power on, look at the remote first. If the batteries are dead, your mini-split won’t turn on. In the majority of situations, putting in new batteries will solve the situation. If you’re still experiencing trouble, reach us at 800-296-5088. Rely on Us for Your Mini-Split Repair NeedsWhen you need mini-split repair or air conditioning repair in Los Angeles, call the company your neighbors and friends have trusted since 1984. Quality workmanship, fair prices and your comfort are our main priorities! Reach us at 800-296-5088 to schedule your appointment right away. Mitsubishi air conditioners are some of the best mini-split ACs around. However, even the best air conditioner will malfunction at some point, and Mitsubishi ACs are no exception. That’s why I’ve put together this complete Mitsubishi air conditioner troubleshooting guide. I’ve put together step-by-step instructions on how to identify and fix every issue your Mitsubishi AC might experience. I’ll also tell you when an issue is complicated that you should call an HVAC repair service instead of trying to fix it yourself. Let’s get to it. This is a large guide, so I recommend that you use this table of contents to quickly jump to the issue your AC is experiencing: Click to jump to the right section for you. hide The Easiest Fix For All Mitsubishi Air Conditioner Problems Mitsubishi Air Conditioner Not Heating/Not Blowing Hot Air Mitsubishi Air Conditioner Not Cooling/Not Cold Mitsubishi Air Conditioner Not Turning On/Not Starting Mitsubishi Air Conditioner Keeps Turning Off Mitsubishi Air Conditioner Leaking Water Inside Mitsubishi Air Conditioner Leaking Water Outside Mitsubishi Air Conditioner Fan Not Working Mitsubishi Air Conditioner Making Noise Mitsubishi Air Conditioner Light Blinking Mitsubishi Air Conditioner Error Codes/Fault Codes Additional Air Conditioner Troubleshooting Resources The Easiest Fix For All Mitsubishi Air Conditioner ProblemsIf you don’t have the time or expertise to troubleshoot and fix your Mitsubishi air conditioner, the smart decision — as you know — is to get an air conditioner repair expert to fix it for you. The problem is that finding a trustworthy and affordable repair service — and actually booking an appointment with them — can feel like pulling teeth. Some services never call you back. Others charge criminally high rates. The best options are often booked out for months… and the worst don’t even fix your air conditioner. (But they charge you for it anyway.) To save you from that teeth-grinding frustration and bring you fast and affordable repairs, I’ve partnered with a helpful company called Networx. They work with thousands of top-rated contractors across the United States, and they make it easy for you to get free A/C repair quotes from the best repair services near you. Here’s how it works in 8 easy steps:
Using this form to find the best repair rates is 100% risk-free. There is zero obligation to hire any of the vetted contractors who contact you. Fill out the form now to find the most affordable repair services in your area. Mitsubishi Air Conditioner Not Heating/Not Blowing Hot AirA Mitsubishi AC that’s not heating has a wrong operation mode setting or higher room temperature than the set temperature. Also, the Heat mode may not have taken effect yet or the AC is too small for the space. A wrong mode setting is the most common cause. Simply set the AC on the Heat/Auto mode. Wrong Mitsubishi AC Mode Setting/High Room TemperatureIf your Mitsubishi AC model allows you to switch between cooling and heating, you will need to set it on the HEAT mode for it to blow hot air. You can also set it on the AUTO mode, which allows your AC to switch mode according to room temperature. On the HEAT mode, your Mitsubishi AC will blow warm air until the set temperature is attained. After that, the compressor will switch off gradually then restart again when the room temperature falls below the set temperature. On the AUTO mode, your Mitsubishi AC will switch from COOL to HEAT mode depending on the temperature: switch to COOL mode if the room temperature is 2 degrees higher than the set temperature for 15 minutes and switch to HEAT mode if the room temperature is 2 degrees lower than the set temperature for 15 minutes. How to Diagnose Wrong Mitsubishi AC Mode SettingCheck to ensure that your Mitsubishi AC is set on either the HEAT or AUTO mode and not the COOL or DRY mode. How to Fix Wrong Mitsubishi AC Mode Setting/High Room TemperatureIf your Mitsubishi AC is not heating but it’s set on the COOL or DRY mode, use the AC’s remote control to select the HEAT or AUTO mode by pressing the MODE button until the desired mode is displayed. The Mode operation changes from AUTO → COOL → DRY → HEAT in that sequence: Mitsubishi Electric recommends that you set your AC on the AUTO mode so that the cooling unit adjusts to change in room temperature based on the set temperature. The Heat Mode has not yet Taken EffectWhen you start the Heat mode on your Mitsubishi AC, the unit will take a few minutes before it can start to blow warm air. This is not a malfunction and should not cause you to panic. When the Heat Mode on your Mitsubishi AC has not Taken EffectAllow the AC to warm up and wait until the unit starts blowing hot air without switching the AC off or trying out other commands on the remote control. The AC is too Small for the SpaceAir conditioners are built in sizes that are measured in BTUs: the amount of energy they will be used to heat/cool a specific size of space. If your AC has lesser BTUs than you need to heat your space, then its energy is not enough to heat the room. How to Tell if your Mitsubishi AC is too Small for the SpaceFollow these steps to tell if your Mitsubishi AC is too small for the space:
Note that other space factors may affect how well (or not) your AC heats the space you want to be heated:
How to Fix a Mitsubishi AC that’s too Small for the SpaceThere are two ways you can resolve the issue of an AC that’s too small for the space:
Mitsubishi Air Conditioner Not Cooling/Not ColdIf your Mitsubishi air conditioner is not cooling, the outdoor unit is dirty, the AC is wrong-sized, the air filter is clogged, the AC has low refrigerant levels, or the AC thermistor is bad. A dirty air filter is the most common cause for a Mitsubishi AC not cooling and can be fixed by cleaning. Unmaintained Outdoor UnitA Mitsubishi outdoor unit houses key components of the cooling system like the condenser coil, compressor, fan, and electrical parts. Because of its consistent exposure to rain, sunlight, and debris, the outdoor unit of your Mitsubishi AC needs regular maintenance. If this is not done, accumulated debris, dust, and other particles can block the airflow and limit the amount of air that is cooled. Also, accumulated heat due to a dirty outdoor unit can cause your AC not to cool as it should. A Mitsubishi outdoor unit should be well maintained through regular cleaning. How to Diagnose a Dirty Mitsubishi AC Outdoor UnitThe first sign of a dirty outdoor AC unit is poor airflow. However, to confirm that your outdoor unit is dirty, you’ll need to open the top panel by unscrewing it and looking inside to notice any debris that’s stuck in parts of the AC. Look out also for accumulated dust on the condenser coil fins. How to Clean a Dirty Mitsubishi AC Outdoor UnitTo clean your Mitsubishi outdoor unit, follow these steps:
If you do not feel up to the task, and especially if you are not sure you can keep the electrical part dry while you clean your Mitsubishi AC outdoor unit, get a reliable HVAC expert to do the job for you. We can send one to you immediately as soon as you fill and submit the form at the bottom of this article. Wrong-sized AC UnitIf you’ve installed your Mitsubishi air conditioner recently and it not cooling or not cooling enough, the AC unit could be too big or too small for the space that needs cooling. A Mitsubishi AC that’s too big for the space being cooled is rated higher (in BTUs) than what you need for the space. As a result, your room cools faster but with uneven distribution of the cooled air. This causes the compressor to run for shorter cycles leaving your room feeling warmer. Instead, if your Mitsubishi AC is too small for the space being cooled, it is rated lower than what you need to cool the space. In this case, the AC compressor runs nonstop, causing the heat from the cooling process to take up the cooled air and the humidity levels to remain unaltered. Besides, a perpetually running AC could easily malfunction. How to Diagnose a Wrong-sized Mitsubishi AC UnitYour Mitsubishi AC has a BTU rating or the amount of energy required to provide cooled or heated air for a space in square feet. To make out if your Mitsubishi AC is the wrong size for your room, check its BTU rating and read the corresponding space size (in square feet) from a reliable guide like the Energy Star Room Air Conditioner Buying Guide. If the BTU rating corresponds to a lower or higher space size than what is shown, then your Mitsubishi AC is wrong-sized. How to Fix a Wrong-sized Mitsubishi AC UnitEnsure you buy the right size of Mitsubishi AC for the space you want to cool from the very beginning. You can do that by:
Note: If you’ve already purchased a wrong-sized Mitsubishi air conditioner, replace it with the correct size as this will save you money in energy bills and ensure you get the proper cooling for the room. Clogged Air FilterCooling relies on a steady airflow in and out of the AC unit. If your Mitsubishi AC has a dirty and clogged air filter, the airflow is compromised and your unit will not cool as it should. The obvious solution for a dirty air filter is to clean it if your AC has a permanent filter or replace it if your AC uses a disposable filter. How to Diagnose a Dirty/Clogged Mitsubishi AC Air FilterTo check whether your Mitsubishi AC air filter is dirty, open the front panel of the indoor unit to reveal the filter and check it for dirt and clogging. How to clean a Dirty/Clogged Mitsubishi AC Air FilterMitsubishi Electric recommends cleaning your AC air filter every 2 weeks to enhance AC efficiency and avoid inflated power consumption. Follow these steps to clean your Mitsubishi AC air filter.
Low Refrigerant (Freon) LevelIf your Mitsubishi AC is low on refrigerant due to a leak, your AC will not cool as expected. This is because the refrigerant is supposed to absorb the heat from the air during the cooling process. If the AC is low on refrigerant, it will not absorb the heat or cool the air fast enough, causing it to work extra hard. Besides low refrigerant and continuous cooling can cause the coils to freeze up. How to Diagnose Low Refrigerant Levels in Mitsubishi ACIf your Mitsubishi AC is low on refrigerant, you will notice some or all of these signs:
A professional diagnosis is required for low refrigerant levels. As such, you should call a professional HVAC if you notice the above signs and you have checked for all other causes of a Mitsubishi AC not cooling. How to Fix Low Refrigerant Levels in a Mitsubishi ACFixing AC refrigerant issues requires professional HVAC skills. You should, therefore, call a Mitsubishi AC expert to ascertain that your AC is low on refrigerant, evacuate it of the existing refrigerant, and recharge your AC with the recommended level of refrigerant. Since this is a costly service, you might want to talk to the HVAC professional about the better option between recharging the AC with refrigerant and buying and installing a new one. We can help you with finding a reliable Mitsubishi HVAC professional once you fill and submit the form at the bottom of this article. Bad Air Conditioner ThermistorThe thermistor is a part of the AC that works with the thermostat to send signals to the compressor and fan when it’s time to start running and cool air for your room (once the temperature you’ve set on the thermostat is surpassed). If the thermistor is bad, it will not send the required signal to get your AC running and your room will not be cooled. Alternatively, you might also see incorrect temperatures displayed on the thermostat or extreme temperature fluctuations. All this does not let your AC cool as it should. How to Diagnose a Bad Thermistor on your Mitsubishi ACThe first sign of a bad AC thermistor is irregular cooling cycles. Your AC will cycle on and off randomly without following the typical 10-15 minute rotations. A bad thermistor will also display incorrect room temperatures, oftentimes showing extremely high-temperature levels at one time and extremely low-temperature levels the next minute. Apart from these signs, you can manually check if your AC thermistor is failing by following these steps:
How to Fix a Bad Thermistor on your Mitsubishi ACIt is best to call a professional HVAC technician to carry out the testing and replacement of a bad thermistor, especially if you are not sure you can do the above process correctly. Frozen Evaporator CoilThe evaporator coil is a part of the indoor AC unit that absorbs the heat from the air so that it can be sent as cool air to your home. If the evaporator coil is frozen due to poor airflow (the air filter is clogged, the airways are blocked, there’s a refrigerant leak, or the AC is short cycling), it will not absorb the heat and your AC will not blow cold air. How to Diagnose Frozen Mitsubishi AC Evaporator CoilTo check if your Mitsubishi AC evaporator coil is frozen, open the front panel of the indoor unit and pull out the air filter to reveal the coil. Check for any signs of ice build-up. Even before opening your cooling unit, you may tell that your AC has a frozen evaporator coil if you notice:
How to Fix a Mitsubishi AC Frozen Evaporator CoilPerform the following if your Mitsubishi AC evaporator coil is frozen:
Mitsubishi Air Conditioner Not Turning On/Not StartingIf your Mitsubishi AC won’t start, the wall outlet could be faulty or has an overload, the circuit breaker may be tripped, or the power cable may be faulty. These are not common faults but, you can avoid a wall outlet overload by not plugging other appliances into the same wall outlet with the AC. Wall Outlet OverloadElectrical wall plugs are made with a standard voltage load. If too many appliances are plugged into one wall outlet through an electrical extension or adapter, the wall outlet could have an overload and short. How to Check and Prevent Wall Outlet OverloadA typical electric wall plug can handle 1,800 watts, which is what most breakers carry: 15 amps and supply 120 volts (Watts = A x V). You can also have a breaker size of 20 amps supplying 120 volts which is around 2,400 watts. For example, if your Mitsubishi AC already takes up 1,600 watts of a 1,800 watts outlet, it should not be plugged into the same wall outlet with other appliances to prevent overload. As a rule, plug only your AC into the wall outlet and do not use electrical extensions as these can have voltage differences. Tripped Circuit BreakerA surge in the power supply can cause the circuit breaker to trip. This means the breaker shuts electrical flow to protect the circuit from overheating and the consequent damage or electrical fire. A circuit breaker may also trip due to a ground fault or a short circuit. Even when the power supply is normalized, your circuit breaker switch will not resolve on its own. This explains why your AC may not turn on when it needs to start a cooling cycle. How to Determine if a Circuit Breaker is TrippedTo check if the circuit breaker supplying power to your Mitsubishi AC has tripped, open the circuit breaker panel and check if the switch is down (switched off). How to Fix a Tripped Circuit BreakerIf the circuit breaker is tripped, carefully turn the switch back on by lifting it up. Note that you should not try to force a circuit breaker switch back on if it feels hard to move as that could mean more damage. If the circuit breaker is not tripped (all switches are turned on) but no power is being supplied, the circuit breaker could be faulty and you need to call an expert electrical technician. Damaged Mitsubishi AC Power CordThis is not a common occurrence, but a Mitsubishi AC power cord that’s not transmitting voltage will cause your AC not to turn on. Also, AC power cords with physical signs of damage such as a broken or frayed cord are faulty and should not be used in the first place. How to Diagnose a Faulty Mitsubishi AC Power CordTo test if your Mitsubishi AC power cord is damaged:
How to Fix a Faulty Mitsubishi AC Power CordElectrical AC issues should always be left to a trained HVAC or electrical expert. As such, never attempt to repair faulty power cables by yourself as this could cause damage to your AC or initiate electrical fires. If your Mitsubishi AC power cable does not show continuity, contact a Mitsubishi dealer near your place for replacement or get help using the Mitsubishi Electric Telephone Support page. You can also seek direct help by calling the Mitsubishi Electric Trane HVAC US customer care number (1-855-923-3631). Mitsubishi Air Conditioner Keeps Turning OffA Mitsubishi air condition that keeps turning off has power supply issues (most common), a faulty thermostat, low refrigerant levels, or the AC could be too big for the space being heated. Also, the thermostat could be installed in a bad position where room temperature cannot be correctly detected. Power Supply IssuesAn unreliable power supply is probably the first thing you should think of if your Mitsubishi air conditioner keeps turning off. That could mean regular power surge or short circuits, a loose power cable, or defective electrical wires of the thermostat, compressor, fan motor, or control board. How to Diagnose Power Supply Issues in a Mitsubishi ACCheck to ensure that your Mitsubishi AC power cable is not loose as this could cause it to go on and off depending on when electrical contact is complete or broken. This is most likely to happen at the side that’s connected to the AC. Monitor the circuit breaker to see if it has regular power surges or short circuits. Test cables and AC parts you suspect have power issues for continuity using a multimeter. You can check the User’s Manual of your Mitsubishi AC to find out how much voltage the cable or AC part should be recording. How to Fix Power Supply Issues in a Mitsubishi ACReplace an AC power cable that is loose and does not provide consistent power. You can do that at the Mitsubishi dealer closest to you or contact Mitsubishi Electric Support. If your Mitsubishi AC has parts that do not record continuity, call an expert HVAC technician to attend to the issue and don’t attempt resolving it by yourself. We can send you an HVAC pro to help you with Mitsubishi AC power issues once you fill and submit the form at the bottom of the article. A Faulty ThermostatThe thermostat controls the cooling cycles in a Mitsubishi AC by signaling the compressor and fan to start running when the set temperature is surpassed and to stop running when the set temperature is achieved. If the thermostat is faulty so that it sends a ‘stop cooling’ signal before the typical 10 to 15-minute cycle is complete, your Mitsubishi AC will keep turning off. This means your space will never be cooled as it should. How to Diagnose a Faulty Mitsubishi AC ThermostatCheck your AC thermostat and notice if the set temperature keeps fluctuating from abnormally high to abnormally low temperatures. Also, notice if your AC thermostat turns off and on due to power issues as this also means your AC is short-cycling. How to Fix a Faulty Mitsubishi AC ThermostatA faulty Mitsubishi AC thermostat will need to be replaced. Contact an HVAC pro and have the expert confirm that the thermostat is indeed faulty before replacing it with a functional one. Bad Thermostat PositionAn AC thermostat works by detecting the surrounding temperature levels and then signaling the AC to start or stop cooling depending on the prevailing temperature. If you position your AC thermostat in a location where there is secondary heat or cold (where there’s a cooler or direct sunlight), it is going to be recording faulty room temperatures depending on whether it is running the Heat or Cool mode. Consistent secondary cool air will make the thermostat continuously signal the AC to turn off. How to Diagnose Bad Thermostat PositioningTry to temporarily eliminate the source of secondary cool air and see if the problem with your AC turning off continuously is resolved. That could mean moving the cooler or other sources of cool air away from the thermostat. How to Rectify Bad Thermostat PositioningIf temporality eliminating the secondary source of cool air resolves the issue with your thermostat, relocate the thermostat to a central position where it can detect the room temperature correctly. The AC is too Big for the SpaceIf you have a Mitsubishi AC that has a higher BTU rating than what’s needed for the space you are cooling, the AC will go for shorter cooling cycles (keep turning off in shorter cycles). This is because more cool air will be dispensed quickly and the space around the cooler will be cooled fast. But, that also means the air distribution will not happen gradually and there will be an uneven distribution of cool air: you will feel cooler in one position and warmer in another position of the same room. How to Tell if your Mitsubishi AC is too Big for the SpaceFollow these steps to tell if your Mitsubishi AC is too big for the space being cooled:
How to Fix a Mitsubishi AC that’s too Big for the SpaceFollow the above steps to determine the size of AC you need for your space before purchasing your Mitsubishi air conditioner. If you are already using an AC that’s bigger than what’s needed for the space being cooled, consider replacing it with the correct size as this will save you money in power bills. The cool air from your AC will also be evenly distributed. Low Refrigerant LevelsThe refrigerant in your AC has the function of absorbing the heat from the cooling process. If your Mitsubishi AC is low on refrigerant due to a leak, it will not perform its heat-absorbing role properly and the cooling process will not run smoothly. This could mean that the pressure levels in the compressor are altered and your AC will keep short-cycling. How to Diagnose Low Refrigerant Levels in Mitsubishi ACA low refrigerant level in an AC is a diagnosis that can only be made by a professional HVAC technician. However, if you notice any of the following signs, your AC could be low on refrigerant/Freon and you should consider calling a professional Mitsubishi AC expert:
How to Fix Low Refrigerant Levels in a Mitsubishi ACCall an expert HVAC pro if you notice any of the signs of low AC refrigerant levels. The HVAC expert will:
We can help you find a reliable HVAC to take care of refrigerant issues in your AC once you fill and submit the form at the bottom of this article. Mitsubishi Air Conditioner Leaking Water InsideIf your Mitsubishi AC is leaking water inside, the drain hose is cracked or wrongly installed, the humidity levels are extremely high, the indoor unit is installed in a slanting position, or the evaporator coil is frozen. The most common cause is a blocked drain line, easily resolved with cleaning. Drain Hose ProblemsThe indoor drain hose can cause leaks if it is wrongly installed, has a crack, is bent and causes a reverse flow, or is blocked. How to Fix Mitsubishi AC Drain Hose ProblemsEnsure your Mitsubishi AC drain hose is correctly installed from the very beginning. This means that the drain hose should not be slanting upward or have any bends. Also, ensure that the drain hose is always clear without any blocks and that it has no cracks. Replace or repair a cracked drain hose. High Humidity Levels inside the Living SpaceDuring the cooling process, both heat and moisture are removed by your AC from the cooled air that’s sent to your home. The moisture is then used to enhance your AC’s efficiency and any extra moisture is sent to the drain pan and out of the cooling unit through a drain pipe. If there’s too much moisture inside your living space, plenty of moisture will be produced from the cooling process, which can cause the drain pan to overflow and leak. How to Diagnose High Humidity Levels inside the HomeYour AC thermostat will show the current humidity levels. Alternatively, you also can check from your smartphone weather widget. You may also notice these signs if the humidity levels inside your home are high:
Healthy humidity levels are between 30% and 50%. If the humidity levels in your home are higher than that, your AC will likely produce extra moisture. How to Fix High Humidity Levels inside the HomeEven though your Mitsubishi AC will have to work harder in high-moisture conditions, moisture levels will go down after some time running the AC. Nonetheless, you can help your AC work less by reducing moisture levels by one or more of the following ways:
Uneven AC InstallationYour indoor Mitsubishi AC unit has a drain pan that collects moisture from the cooling process and sends it out of your home through the drain pipe. If your AC indoor unit is installed in a slanting position so that the water in the drain pan tends to go to one side, it could cause a leak. How to Tell if your Mitsubishi AC is Installed in an Uneven PositionIt is easy to tell if your indoor AC unit is slanting simply by looking at it. Differently, you can open the front panel and remove the filter to check if water from the cooling process is tending to one side of the drain pan. How to Fix a Mitsubishi AC that’s Installed in an Uneven PositionIt’s advisable to have someone with the know-how install your Mitsubishi AC right from the beginning. If a mistake was made and the indoor unit is installed unevenly, consult an expert to correct the mistake and prevent further wall, furniture, or, flooring damage from AC leak. Blocked Condensate DrainThe entire moisture drainage path of your Mitsubishi AC needs to be clear to ensure no water is staying around your AC and not getting properly drained. This means that the drain pan should not be overflowing and the condensate pipe and main drain pipe should be clear and not clogged. If any of these parts are blocked, the drain pan overflows and water could leak down your wall unit to the wall, ground, or any furniture below the unit. How to Diagnose a Blocked Condensate DrainA blocked condensate drain will cause standing water in the drain pan and eventually, send leaking water down the indoor unit. Other signs of a blocked condensate drain include:
How to Fix a Blocked Condensate DrainTo unclog a blocked condensate drain line, follow these 6 steps:
Frozen Evaporator CoilFrost on the evaporator coil happens as a result of poor airflow due to a dirty filter or blocked AC airway. Low refrigerant levels, leaking ductwork, faulty fan blower, or dirt on the evaporator coils can also cause the coils to freeze up. As a result, the ice melts slowly during the cooling process sending extra water down to the drain pan. This could mean that the water drainage pipe is not keeping up with the large amount of water being produced, causing the drain pan to overflow and leak. How to Diagnose Mitsubishi AC Frozen Evaporator CoilIf you notice that your Mitsubishi AC is leaking water inside, open the indoor unit to look for signs of a frozen evaporator coil:
How to Fix Frozen Mitsubishi AC Evaporator CoilIf your diagnosis concludes that the evaporator coil is frozen, leave the AC turned off to allow the ice on your Mitsubishi evaporator coil to thaw You can speed up the thawing process by setting the AC on Fan mode and the fan at high speed for about 15 minutes. Mitsubishi Air Conditioner Leaking Water OutsideIf your Mitsubishi air conditioner is leaking water outside, it is usually because it is working hard on a hot and humid day during the cooling season or the temperature of the condenser coil in the outdoor unit has dropped below the dew point temperature outside. Both are normal AC operations. High Humidity LevelsOn hot summer days with high humidity levels, your AC is forced to work harder to remove the heat and humidity from the air. Also, the high humidity levels come with higher condensate levels. This means more water is drained outside the home. Below Dew Point Condenser Coil Temperature OutsideWhen your AC is set on the Heating mode, the indoor unit blows warm air and raises indoor temperatures. But the outdoor unit is cool from low temperatures and can get extremely cold. If the temperature of the outdoor unit drops below the dew point temperature outside (the temperature at which the air cannot hold any more moisture), condensation/dew forms on the condenser coil of the outdoor unit. This water runs down the coil and collects at the base of the outdoor unit. If your Mitsubishi air conditioner outdoor unit has a small draining hole at the bottom, this water will drain below the unit. If this is not the case, the water will overflow once the base is filled up. Both cases explain why your outdoor unit will be leaking water which, as earlier explained, is a normal operation in the prevailing weather conditions. Mitsubishi Air Conditioner Fan Not WorkingIf your Mitsubishi AC fan is not working, it could be a wrong fan speed or fan mode setting, a malfunctioned thermostat, or a defective fan motor. Wrong fan speed or fan mode settings are more common causes for an AC fan not working, and this can be easily resolved with the correct setting. Wrong Fan Speed/Mode SettingTo distribute cold or warm air, your AC fan should be set on Medium or High speed. Instead, if it is set on the AUTO mode or on low speed, the cool or warm air may not be felt and it will seem like your Mitsubishi AC fan is not working. What to do if your Mitsubishi AC has the Wrong Fan/Mode SettingIf your Mitsubishi air conditioner doesn’t cool or heat effectively because the Fan mode or speed is wrongly set, simply use the Fan button on your remote control and press until you can choose the Med. or High speed. Your AC fan should start working. Malfunctioned ThermostatThe fan in your Mitsubishi AC starts to run every time the thermostat sends a signal that the temperature in the room has risen above the set level. This prompts both the fan and the compressor to start running. If the thermostat has malfunctioned, it will send faulty signals, which could be that the temperature in the room is lower than the set level always and the fan does not need to run, which is why the fan will not work. How to Diagnose a Faulty Mitsubishi AC ThermostatIf your Mitsubishi AC thermostat has malfunctioned, it might show a blank screen or indicate extremely low or extremely high-temperature levels. How to Fix a Faulty Mitsubishi AC ThermostatA faulty thermostat needs to be replaced. Contact a professional HVAC if your Mitsubishi AC thermostat is acting up and giving erroneous temperature figures and have the thermostat replaced. We can hasten the process for you by sending the expert Mitsubishi AC pro as soon as you fill and submit the form at the bottom of this article. Defective Fan MotorA defective fan will not serve its function of blowing cool/warm air to your room. If the fan motor is faulty or has voltage issues, it is not going to be spinning as it should. How to Diagnose a Defective Mitsubishi AC Fan MotorYou’ll need to open the AC compartment that houses the fan and try spinning the fan manually. If the fan spins without much effort, it probably has voltage issues. But if it is hard to turn and spin, the motor bearings are most likely worn out and need to be replaced. How to Fix a Defective Mitsubishi AC Fan MotorHave an expert HVAC technician check and service a defective AC fan motor. We can connect you with a reliable Mitsubishi AC expert as soon as you fill and submit the form at the bottom of this article. Mitsubishi Air Conditioner Making NoiseIf your Mitsubishi AC is making abnormal noise, the AC may have been installation badly or there are loose/broken AC parts making noise while the cooling unit is in operation. A dirty air filter is a common cause of a noisy Mitsubishi AC and should be prevented by cleaning the air filter regularly. It’s important to differentiate between normal and abnormal Mitsubishi AC noises. Normal noises (not malfunctions) include:
Other loud noises should be considered malfunctions and can be caused by the following issues: Improper AC InstallationMitsubishi AC recommends that an air conditioner be installed by an expert with specialized knowledge. This is because improper AC installation can cause electrical faults, water leakage, noise from improperly fixed parts, or failure of the AC to initiate the cooling process. How to Fix Improper Mitsubishi AC InstallationEnsure that your Mitsubishi AC is installed by the dealer or technician with specialized knowledge from the very beginning. The installer should consult the Mitsubishi AC Installation Manual for the model step by step. If an installed Mitsubishi AC is making noise due to improper installation, consult your dealer and have the installation issue corrected. Loose/Broken AC PartsIf your Mitsubishi AC has loose or broken parts, they will move and shake when the unit is in operation and cause a rattling noise. Loose or broken parts could be the front panel, the fan, or the air vanes. How to Inspect and Fix Loose/Broken Mitsubishi AC PartsDelicate AC repairs are best done by an expert HVAC technician. Contact a Mitsubishi dealer near you or call Mitsubishi Electric Support about broken Mitsubishi AC parts. Ensure that the front panel and the vanes are installed according to the instructions on your Mitsubishi AC model’s Installation Manual. If you need to fasten loose Mitsubishi AC parts and are not sure what to do, call in an HVAC pro to do the job. If you need a hand, we can connect you with a reliable HVAC pro once you fill and submit the form at the bottom of this article. Dirty Air FilterA dirty air filter is always bad news when it comes to air conditioners. If your Mitsubishi AC filter is dirty, airflow is restricted and the compressor will be working extra hard to supply the required cool air with little air supply. How to Diagnose a Dirty Mitsubishi AC Air FilterOpen the front panel of your indoor Mitsubishi AC unit by lifting the panel till you hear a click and then pulling the panel towards you while holding the hinges. Doing this will reveal the filter and you can check if it’s covered with dirt. How to clean a Dirty Mitsubishi AC Air FilterTo clean a dirty Mitsubishi AC air filter, follow these instructions:
Mitsubishi Electric recommends cleaning the air filter every 2 weeks and the Air Cleaning Filter every 3 months and replacing it every year. Mitsubishi Air Conditioner Light BlinkingIf your Mitsubishi AC lights are blinking, they could be indicating abnormal operation such as a faulty power control board, communication error between the indoor and outdoor units, an overheated compressor, or outdoor fan issues. Typical Mitsubishi AC light blinking happens in normal operation when you press a button on the remote control to send a command to your AC. But, atypical blinking is indicative of abnormal operation and should be attended to by an HVAC pro, unless your User’s Manual gives simple troubleshooting guidelines. Below are some of the most common Mitsubishi AC light blinking cases that are indicative of abnormal operation. Note that we can send you a reliable Mitsubishi AC professional to resolve any light-blinking AC issues as soon as you fill and submit the form at the bottom of this article. Mitsubishi Air Conditioner Light Blinking 14 TimesMitsubishi air conditioner light blinking 14 times is an indicator that “the power module is out of order.” This could be caused by issues with the power control board, causing key parts like the compressor to run abnormally. How to Fix Mitsubishi AC Light Blinking 14 TimesCall in an expert HVAC technician to assess the issue by:
Mitsubishi Air Conditioner Timer Light Blinking 2 TimesIf your Mitsubishi air conditioner time light blinks 2 times, it has detected an “Outdoor heat exchanger liquid pipe sensor error.” This could be caused by one or more of these situations:
How to Fix Mitsubishi AC Timer Light Blinking 2 TimesDo not attempt to resolve AC power issues by yourself. Instead, call an expert HVAC pro or a trained electrician to assess and resolve the issue. Mitsubishi Air Conditioner Timer Light Blinking 6 TimesIf your Mitsubishi air conditioner timer light blinks 6 times, there is an “Error of communication between indoor and outdoor units.” This is usually caused by one of these situations:
How to Fix Mitsubishi AC Timer Light Blinking 6 TimesPower-related Mitsubishi AC issues should always be resolved by an HVAC expert or trained electrician. Mitsubishi Air Conditioner Timer Light Blinking 5 TimesIf your Mitsubishi air conditioner timer light blinks 5 times, the AC “compressor has overheated.” This can be caused by:
How to Fix Mitsubishi AC Timer Light Blinking 5 TimesAlways call a reliable Mitsubishi AC expert or a trained electrician to resolve power-related issues with your AC. If your Mitsubishi AC compressor is overworked due to issues like poor airflow, resolve the root cause of the problem. Mitsubishi Air Conditioner Timer Light Blinking 7 TimesMitsubishi air conditioner timer light blinking 7 times is an “outdoor fan motor error.” This happens only with a DC motor. The fan motor error can occur as a result of one of these causes:
How to Fix Mitsubishi AC Timer Light Blinking 7 TimesCall a reliable Mitsubishi AC expert or a trained electrician to assess a defective motor and other electrical faults with your AC. Do not attempt to resolve them by yourself to prevent electrical accidents or damage to the AC. Mitsubishi Air Conditioner Yellow Light FlashingThe yellow light on your Mitsubishi air conditioner is on during timing operation. If it starts flashing, it means that there’s failure in a wire connection. Note that the yellow light on your Mitsubishi AC may start flashing when other error codes are displayed. Mitsubishi Air Conditioner Green Light BlinkingThe green light on your Mitsubishi air conditioner lights during operation. But, if the green light is blinking, the airflow has stopped due to the “CLEAN” operation. Note that the green light on your Mitsubishi AC may start flashing when other error codes are displayed. Note also that the meaning of blinking lights on your Mitsubishi AC may vary with different models. Mitsubishi Air Conditioner Error Codes/Fault CodesMitsubishi air conditioner error codes indicate abnormal operation in your cooling system including abnormal pipe temperature, abnormal high pressure, receiving or transmitting communication error, freezing or overheating, drain overflow, or abnormality of power module among others. We present some of these common Mitsubishi air conditioner error codes, what they indicate, their causes, and what the HVAC pro will do to resolve them when troubleshooting is not an option. Mitsubishi Air Conditioner Error Code P8Mitsubishi air conditioner Error Code P8 is an abnormal “pipe temperature” error that occurs in both the cooling and heating modes of the AC. In the cooling mode, the pipe temperature is detected as abnormal when the temperature does not get into the cooling range (-3℃) 3 minutes after the compressor starts running and 6 minutes after the liquid/condenser pipe is not in the cooling range (9 minutes in total to be detected). This error does not happen in the Dry mode. In the heating mode, the pipe temperature is detected as abnormal when the condenser pipe temperature is not in the heating range (3℃) 20 minutes after the compressor starts running excluding the defrosting period (27 minutes in total to detect pipe temperature). Abnormal pipe temperature can be caused by:
How to Fix Mitsubishi AC Error Code P8Contact an HVAC pro to:
Mitsubishi Air Conditioner Error Code 1302Mitsubishi air conditioner Error Code 1302 (U1) is an “abnormal high pressure error.” This error code occurs in a variety of situations including:
How to Fix Mitsubishi AC Error Code 1302 (U1)Call an expert HVAC to resolve Mitsubishi AC Error Code 1302 (U1). The HVAC expert will:
Mitsubishi Air Conditioner Error Code E6Error Code E6 (6840) on your Mitsubishi air conditioner is an “indoor/outdoor unit communication error” or “signal receiving error” detected by the indoor unit. This communication receiving error will display when the indoor controller board does not receive the usual signal after power is turned on for 6 minutes or the indoor controller board does not receive any signal for 3 minutes during operation. Error E6 on your Mitsubishi AC can be caused by:
How to Fix Mitsubishi AC Error Code E6 (6840)You can try resetting the AC by turning off the power and back on again. If this does not resolve the issue, call an expert HVAC to resolve Mitsubishi AC Error Code E6 by:
Mitsubishi Air Conditioner Error Code U6Error Code U6 (4250) on your Mitsubishi air conditioner is an “abnormality of power module” error. The error code will present in the following situations:
How to Fix Mitsubishi AC Error Code U6 (4250)Call a Mitsubishi AC expert to resolve Error Code U6 by:
Mitsubishi Air Conditioner Error Code P6Mitsubishi air conditioner Error Code P6 is a “freezing/overheating” warning. It is accompanied by 3 times blinking on the red LED and may occur during both the cooling and heating season as per the status of the AC. How to Fix Mitsubishi AC Error Code P6An HVAC expert will assess and fix Mitsubishi AC Error Code P6 by:
Mitsubishi Air Conditioner Error Code E9Mitsubishi AC Error Code E9 (6841) is an “indoor/outdoor unit communication error” or “transmitting error.” The error is displayed when the unit controller board does not find any transmission path for 3 minutes. The communication transmission error can be caused by:
How to Fix Mitsubishi AC Error Code E9 (6841)Try resetting the AC by turning off the power and back on again to see if the issue is resolved. If not, call a Mitsubishi AC expert to resolve Error Code E9 by checking:
Mitsubishi Air Conditioner Error Code P5Mitsubishi air conditioner Error Code P5 is an “indoor drain overflow” error. It is accompanied by 2 times blinking on the red LED. How to Fix Mitsubishi AC Error Code P5Call an HVAC expert to assess and fix Error Code P5 by:
Note that Mitsubishi error codes may vary by model but, these are the common code errors that will display when there’s an abnormal operation in your AC. If you are not sure about the displaying error on your Mitsubishi AC, you can:
Additional Air Conditioner Troubleshooting ResourcesIf you encounter other problems with your air conditioner, one of our other air conditioner troubleshooting articles help: Why is my Mitsubishi air conditioner not heating?If your air conditioner doesn't seem to be heating or cooling the room properly, check the filters to see if they need cleaning and check the drain pipe for any obstructions. If this doesn't help, contact us direct.
Why is my mini split blowing cold air on heat?The Heat Pump May Have Faulty Components
The system might, in some instances, develop issues that will need repair in order for the heat pump to stop blowing cold air. These common causes may include the reverse valve becoming faulty, leaking refrigerant lines or other faulty components.
How do you reset a Mitsubishi mini split?Follow the same instructions as for the breaker. Turn off the system, switch the isolator to off, wait 30 seconds, switch the isolator back on, wait a couple of minutes, and turn the whole system back on.
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