Mini split AC making strange noises: What to do

So you’re chilling at home, and suddenly your mini split AC starts making all sorts of weird noises, rattles, whirs, bangs, you name it. Not exactly the peaceful cooling you signed up for, right? Let’s dig into what’s causing these strange sounds and figure out how to get your AC back on track.

The tips and info here might not match your exact appliance model. We try our best to share useful DIY repair advice, but different models can have unique quirks, troubleshooting steps, error codes, parts, you name it. For the best results, check your manufacturer’s guide or hit us up if you’ve got questions.

Spotting common mini split AC noises

So, your mini split AC is making weird sounds? First things first, figure out what kind of noise you’re hearing. Different sounds can hint at different issues. By tuning into these audio clues, you can zero in on the problem and troubleshoot like a pro. Here are some noises you might encounter and what they could mean:

• Clicking or tapping: This could mean a loose screw or part that’s shifting when the air kicks in. Sometimes, it’s just the plastic casing expanding or contracting.
• Rattling or banging: Loud rattles or bangs might be a fan blade hitting something, or maybe there’s debris caught up in the blower wheel. Could also be a loose panel or screw.
• Whistling or howling: If it sounds like a whistle, you might have an air leak. Gaps around panels or joints can make high-pitched noises when air sneaks out.
• Humming or buzzing: A quiet hum is usually normal, but if it’s loud and buzzy, that might signal an electrical problem or a motor on the fritz.
• Squealing: Squeals often come from belt-driven parts or worn-out motor bearings. Even though many mini splits don’t have belts, some internal bits can still make a squeal when they’re stressed or worn down.

So now that you know what’s up with those noises, it’s a good start. Before you roll up your sleeves, let’s make sure you’re keeping safety in mind.

Important safety measures

Before you start popping off panels or messing with parts, safety first! Dealing with electrical stuff can be risky, especially when you’re near wires or things that move. Here are some key precautions to keep in mind:

• Turn off the power to the appliance by unplugging it or switching off the circuit breaker before starting any maintenance or repairs. This protects you from the risk of electric shock.
• Wear insulated gloves to shield your hands from sharp edges, pinching hazards, or debris.
• Work at a steady pace and take your time to avoid accidents or injuries.
• Make sure your workspace is well-lit so you can clearly see and access the parts you’re working on.
• Keep the area clear of clutter, and ensure children and pets stay out of the workspace.
• Never handle internal parts with wet hands. Check that both your hands and the work area are completely dry.
• Refer to your appliance’s user manual for any specific instructions or safety guidelines related to the part or repair.
• Handle parts gently to avoid damage to the appliance or potential injuries from applying too much force.
• Use safety glasses when dealing with chemicals, dust, or large debris to protect your eyes from harm.
• If the appliance was recently used, give it enough time to cool down before working on any heated components.
• Take photos or notes of wiring connections and terminals before disconnecting anything to make reassembly easier.
• Avoid touching exposed wires or terminals. If you must handle wires, use non-conductive tools or wear insulated gloves to minimize the risk of electrical shock.

Tools you’ll need

You don’t need to be a pro mechanic or have a fancy workshop to tackle most mini split issues. But having some basic tools handy can make life a lot easier:

• Screwdrivers: Both Philips and flat-head types are good for taking off panels, tightening loose screws, or adjusting brackets.
• Flashlight: A decent flashlight helps you see into those dark nooks and crannies inside the unit.
• Soft cloth or brush: Use these to clean off dust and gunk around the fan and motor. Keeping it clean can cut down on weird noises.
• Vacuum with a small nozzle attachment: Great for sucking out debris in tight spots, especially near the fan.
• Multimeter (optional): If you think there might be electrical issues, a multimeter can help you check things out.

Clearing debris from the unit

Stuff like leaves, dust, little twigs, or even critters can get into your mini split AC and cause all sorts of weird noises, from light clicks to full-on bangs. Getting rid of this junk often gets things back to normal. Here’s how you can do it:

Step-by-step instructions for removing debris

1. Kill the power: Unplug the AC or flip off its circuit breaker.
2. Check out the outdoor unit: Take off any grates or covers and look for leaves, trash, or small branches. Gently pull them out.
3. Vacuum stubborn dirt: Use a small nozzle to vacuum dirt from the condenser fins or fan blades. Be careful not to bend anything.
4. Look at the indoor air filters: Clogged filters can make whistling sounds. Open up the front panel, pull out the filters, and give them a good clean. Let them dry completely before putting them back.
5. Peek at the blower wheel: Some models let you access the blower wheel behind the filter. If there’s junk stuck in there, remove it gently. Spin the wheel by hand to make sure it moves freely.
6. Check the drains: Water buildup can cause gurgling noises. If you think the drain is clogged, clean it with a flexible brush or flush it with water.
7. Put everything back and test: After cleaning and reassembling, power up the AC and listen. If it sounds better, you’re golden.

Tightening loose parts

Loose screws, brackets, or panels are often the culprits behind those annoying rattles and bangs. Even small vibrations can make parts shift or bump into each other. Tightening things up can quiet your mini split AC down. Here’s how to do it:

Step-by-step instructions for tightening parts

1. Cut the power: Unplug the AC or flip the breaker. Make sure everything’s off.
2. Take off the front panel: Most indoor units have a front panel you can open or remove. If it’s screwed on, grab the right screwdriver and keep the screws safe.
3. Check all visible screws and bolts: Look for any that are loose or missing around mounting brackets, fan parts, and panels inside the unit.
4. Tighten ’em up: Use the correct screwdriver so you don’t strip any screws. Turn them snug, but don’t overdo it, you don’t want to crack anything.
5. Inspect the outer casing: If your mini split has an outdoor unit, give the panels a gentle shake to see if anything’s loose or rattling.
6. Put everything back together: Reattach any panels or covers, making sure everything lines up properly.
7. Fire it up: Turn the AC back on and listen. If the rattling’s gone, you nailed it.

Checking motor and fan components

The motor and fan in your mini split AC keep the air flowing and the cool vibes going. But over time, wear and tear or misalignment can cause unwanted noises and vibrations. Fixing these parts up can get rid of squealing, buzzing, or rattling. Here’s how to give your motor and fan a closer look.

Step-by-step instructions for examining motor and fan

1. Power off again: Always start by cutting the power. Wait for the fan to stop spinning.
2. Get access to the fan: Depending on your model, you might need to remove the front or top cover. If you’re not sure how, check the manual or look up how to find your model number.
3. Check for alignment issues: See if the fan blades are wobbling or hitting anything. Gently spin the fan by hand (with the power off!) to make sure it moves smoothly.
4. Clean the fan blades: Use a soft cloth or brush to wipe off dust and grime. If it’s really dirty, a bit of mild detergent on a cloth can help.
5. Inspect the motor shaft: If it feels loose or wobbly, the bearings might be shot. This can cause squeals or grinding noises. Sometimes you can replace the bearings; other times, you might need a new motor.
6. Test with a multimeter (if you’re up for it): If you think the motor’s the problem, a multimeter can help you check. With the power disconnected, set it to ohms (resistance) and follow the manufacturer’s guide for testing.
7. Put it all back and test: After you’re done, reassemble everything, turn the power back on, and listen for any changes.

Finishing touches and extra tips

Thanks for reading! If you have any other appliance repair needs or projects, you can find more resources including our DIY blog at AppliancePartsPros.com. There, you can enter your model number to order the exact parts you need. Most orders arrive in two business days.

You can also reach our award-winning customer service team at 1-877-477-7278, chat with a pro on our website and watch thousands of free video tutorials on our YouTube channel.Make sure to follow us on Facebook, Twitter and Instagram!