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Mini Split A/C Troubleshooting Guide

Mini Split A/C Troubleshooting Guide

When your ductless AC stops working, what would you do? Will you know when it just needs a little fix or it’s time to give it the boot? Will you be able to do a simple check and troubleshooting?

Say it’s the peak of Summer. It’s mid-morning and you’re in a sun-draped car park, just fresh out of the grocery. You’re sweating profusely. No, you’re melting. You can almost feel the hot air burning your skin. With the heat outside at feverish level, you thought you might as well cook those freshly bought eggs on the sidewalk. And as soon as you jumped into the driver’s seat, you began thinking about dousing yourself off with iced water. Or bathing with it even. And then you took off. Fast. Other errands are no longer important. You’re homebound; badly looking forward to crank your AC down to the coolest temp possible that it can provide.

You arrived home, already drenched in sweat after just a minute out of the car. And then you headed straight to the thermostat, and turned it on. It didn’t work. You tried again. Still, it didn’t work. Beads of sweat now running from your forehead. Confusion starts to set in. So you tried again. And again it didn’t work. You tried turning the power button from the main unit itself. Same result. Not even a flicker of bright flash from the light indicator. It just wasn’t working.

Truly, there’s nothing worse than having a broken AC when you need it most. And just when you don’t have extra money to spend on repair. But here’s the thing. When the air conditioner stops working, it doesn’t always mean that the system is broken. Definitely something’s wrong, but it might just be a simple error that can be easily fixed. But for the initiated, a simple system error or a serious one doesn’t make any difference at all—you’re stumped, you have no idea what’s wrong, and you’re usually left there sweating it out but you don’t know what to do.

Now, regardless of whether you’re the average Joe with no background whatsoever about how an AC works or a DIY-type of guy with a bit of a background on HVAC, it is very important to have at least a basic working knowledge on how to check and troubleshoot your AC when it ran into a problem. On this end, this article discusses the common errors that you’ll most likely encounter with your ductless AC and the basic ways to fix these issues. Take note that these are simple problems that you can fix on your own and would not require calling for a service from an HVAC technician. For clarity’s sake, let’s just call these issues the POST (Power, Odor, Sound, and Temperature) problems.

Power Issue: The Unit Wouldn’t Power On

When this happens, always check first the power supply. It’s possible that the power plug is not connected to the power outlet or the circuit breaker is tripped. Check these two things before anything else.

If you’re turning the unit on using the remote controller and it’s not working, the battery may be the problem or the controller itself. More often than not, it’s the former. To check if this is indeed the case, you can try turning the unit on from the main unit itself or from the thermostat device. You can do it vice versa. If you are turning the unit on through the thermostat and it’s not working, then you can also try checking if it works through a remote controller.

If the unit is turned on through the controller, the thermostat device may be broken or encountering an error in terms of connecting to the main AC unit. If both the remote controller and the thermostat can’t be used to turn on the unit, the most likely error is in the system itself. But that is a rare case. The usual case is, when the unit wouldn’t turn on, either your unit was disconnected to the power supply, the circuit breaker is tripped, or the controllers have a battery problem. Other serious causes are possible, such as failed capacitor or burnt out compressor, but these things may already require technical help from a professional and sometimes a parts replacement.

Odor Issue: The Unit Emits Foul Odor

When your ductless AC starts to emit an unpleasant odor, it’s most certainly a sign that your unit is dirty inside. It indicates that there is already a growth of dirt, mold, and mildew within the unit. The fact that you already smell a nasty odor means that the problem is serious enough to the point that these foul-smelling dirt have already contaminated the air that circulates inside your room.

To understand the source of this odor, you need to know that your ductless air conditioner works by absorbing the warm air from inside your room. This warm air passes through cool evaporator coils, causing condensation to happen. This produces condensate or moisture, which is basically a water. This water drips into the condensate drain line down to the drain pan. The problem occurs when the coils and drain pan become clogged with dirt due to overuse and poor maintenance.

Naturally, when condensate water is mixed with dirt, it causes mold to develop. Additionally, the clogged dirt prevents excess moisture to drain properly. With mold and stagnant water collected inside the system, it’s only a matter of time before it develops a foul smell. When your ductless system emits foul odors, it becomes an air filter issue. It means that your unit’s air filter is already too dirty and clogged up with dirt. As a result, it is no longer effective in screening out dirt that goes inside.

What you can do is to simply clean the air filter and the condensate drain line and pan. Most ductless mini splits usually come with washable air filters, so these would be an easy task without any extra expense on your part. To avoid similar problem in the future, you just have to clean the air filter regularly. Washing them with soap and water will go a long way to make these filters last for many years. To ensure the efficiency of your system, don’t forget to follow the manufacturer’s recommendations when it comes to cleaning or replacing air filters.

Sound Issue: The Unit is Noisy

Mechanical devices like air conditioners normally produce noise. But unlike conventional AC systems, ductless ACs typically operate quietly. They produce a sound while in operation, but very quiet. When your ductless AC unit starts to produce an abnormal noise, such as a loud clanking, rattling, banging, squealing, humming, thumping, or screeching sounds, then it means that there is a problem within the system. Most likely, the cause of abnormal noise that comes from the unit is a bent or dirty fan blade, loose cabinet, or there may be some debris inside that’s causing friction with other components. A simple clean up and tightening of those loose parts will do the trick.

Temperature Issue: The Unit is Not Blowing Enough Cool Air

Many things can actually happen inside the ductless mini split system that may result in a poorly distributed air conditioned air. But this is a very common problem. A dirty unit is one of the usual causes. Dirt can easily accumulate inside your system, whether in the outdoor unit or the indoor unit. Your best course of action is to check both units and try to clean most if not all of the dirt that you can find. In the indoor unit, you can start by cleaning or replacing the air filter. You can also clean the fan if it is accessible. In the outdoor unit, some dirt and debris such as twigs and leaves may be blocking the smaller mechanisms inside, which is preventing the system from properly working in terms of distributing air. When this is the case, try to clear the unit with any kind of obstruction. You can also clean the surrounding area. One of the other possible reasons is a low level of refrigerant in the system. When this happens, the likely cause is a leak. A repair of the leak and recharging of refrigerant may require you some professional help.

Regular Maintenance is Key

Just remember that there is no perfect machine. Like any type of system, your ductless air conditioner has its limits. There are many factors that affect the performance and overall lifespan of your mini split unit. It could be due to wear-and-tear, age of the system, extreme climate in the area where you live, improper use of the unit, or lack of maintenance. Ideally, ACs can last up to 12-15 years. A properly maintained ductless mini split can even stay functional up to 20 years. Yes, it is inevitable that you AC will break down at some point, but it is safe to say that proper use will ensure that this will not happen too soon. I simple product like the PurCool Green Mini Strips can help keep your system free of mold and mildew of 4-6 months.  

Additionally, preventative maintenance will help you keep the unit in good condition and help prevent early breakdowns. Occasionally, you AC might run into errors. Having knowledge about the usual errors and the correct troubleshooting steps to be followed will help you save a lot of money and stress from costly repairs.



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