How to Reset Mitsubishi Air Conditioner (Complete Guide for Singapore Homes)

338 Aircon
3 days ago
7 min read

Is your Mitsubishi air conditioner acting up? Maybe the remote isn't working, the lights are blinking, or your unit is blowing warm air instead of cool air. Before you panic and call for service, there's a quick and easy fix you can try at home: resetting your Mitsubishi aircon.

In this comprehensive guide, we'll explain exactly how to reset a Mitsubishi air conditioner, when to do it, and what to check if a reset doesn't solve the issue.

Whether you own a split system or a ceiling cassette Mitsubishi air conditioner model, this step-by-step reset guide is designed for homeowners in Singapore who want fast results without hassle.

Understanding Your Mitsubishi Air Conditioning System

Before diving into reset procedures, it's helpful to understand the basic components of your air conditioning unit:

Indoor unit: Contains the evaporator coil, air filter, and fan that distributes cool air throughout your space
Outdoor unit: Houses the aircon compressor, condenser coil, and fan that releases heat outside
Remote controller: Controls temperature, fan speed, swing mode, and other settings
Control board: The electronic "brain" that manages all system functions

Mitsubishi electric air conditioners are known for their reliability, but like most air conditioners, they can experience occasional glitches that affect performance.

When Should You Reset Your Mitsubishi Air Conditioner?

Resetting your aircon helps clear minor errors and software glitches that build up over time. Here are common signs it's time for a reset:

🌀 Air conditioning is running but not blowing cold air
🔁 Blinking lights on the indoor unit or remote's control panel
📴 Remote control becomes unresponsive with a blank screen
⚠️ After a power outage, surge, or tripped circuit breaker
🔄 After cleaning filters or performing basic maintenance
🌡️ Thermostat malfunction or incorrect thermostat settings
⏲️ Issues with faulty timer or auto mode

Think of it like rebooting a computer—it often resolves small issues instantly and can restore optimal performance to your Mitsubishi AC system.

How to Reset Mitsubishi Air Conditioner: Step-by-Step

If your Mitsubishi AC unit isn't working properly, follow this simple reset procedure:

Standard Power Reset

✅ Step 1: Turn Off the Air Conditioner

Use your remote controller to power off the aircon completely
Press the power button until the unit shuts down

🔌 Step 2: Switch Off the Power Supply

Locate your aircon's isolation switch or circuit breaker (usually labeled "A/C" or "Air Conditioner") on your home's breaker board
Flip it off completely
If you have multiple units, ensure you're switching off the correct one

⏱️ Step 3: Wait 2 to 5 Minutes

Give the system time to discharge and reset its internal memory
This waiting period is crucial for the electronic control board to fully reset

🔁 Step 4: Turn the Circuit Breaker Back On

After waiting, flip the breaker switch back to the ON position
Check that the switch is firmly connected

🎛️ Step 5: Turn the Aircon Back On

Use your remote to restart the system
You should hear the unit power up normally
Set to your desired temperature and fan speed

Remote Control Reset

💡 Note: Some models have a small ACL (All Clear) button on the remote. Use a paperclip to press and hold it for 3–5 seconds to reset the controller.

By following these steps, you'll perform a full power reset on your Mitsubishi air conditioner, which often resolves minor electronic glitches.

How to Reset the Mitsubishi Remote Control

Sometimes the problem isn't the unit, but the remote. If your Mitsubishi remote control is not working or showing a blank screen, try this reset procedure:

Remove the batteries from the controller
Press any button for 10 seconds to drain any residual power
Clean the battery contacts with a dry cloth
Insert fresh batteries, ensuring proper polarity
Check if any button light appears when pressed
Test by turning the aircon on again and adjusting settings

If the remote still doesn't work after reset, you may need a replacement controller. Universal remote controls compatible with Mitsubishi air conditioning systems are available if you need a temporary solution.

Specialized Resets for Specific Issues

Reset for Horizontal Vane or Swing Issues

If your Mitsubishi air conditioner swing function isn't working correctly:

Turn off the unit using the remote
Press and hold the "Vane Control" button for 5 seconds
The vanes should reset to their default position
Turn the unit back on and test the swing mode

Reset After Filter Cleaning

Blocked filters and dirty filters are common causes of limited airflow and poor cooling. After cleaning:

Reinstall the clean filters properly
Reset the "Filter" indicator if illuminated (typically by holding the "Filter Reset" button for 3 seconds)
Perform a standard power reset as described above
Run the unit to ensure proper airflow has been restored

Troubleshooting After Reset

Resetting works in most minor cases, but here's what to check if your issues continue:

🧊 Still Not Cooling?

If your Mitsubishi AC isn't producing cool air after reset, check that:

The filters are clean and not causing limited airflow
The thermostat is set below room temperature
Doors and windows are shut tight to maintain the indoor environment
The outdoor unit is free from obstructions
The fan speed is set appropriately for the room size

💡 Blinking Light Still On?

A blinking light on your control panel can indicate an internal error. Count the number of blinks as this often corresponds to specific error codes in your troubleshooting guide. Common codes might indicate:

Faulty components in the system
Problems with the control board
Issues with the power button or other buttons
Sensor failures affecting set temperature readings
Faulty motor damper or fan limit problems

🔊 Strange Sounds?

Unusual noises post-reset may signal:

Fan motor issues affecting the indoor or outdoor unit
Damaged isolation feet on the compressor
Faulty compressor operation
Loose components inside the unit

What If Reset Doesn't Work?

If resetting doesn't solve your problem, your Mitsubishi air conditioning might need deeper diagnostics.

Here are some potential issues:

🧪 Low refrigerant levels affecting cooling capacity
⚠️ Faulty temperature sensors causing thermostat malfunction
🔧 Blocked or leaking drainage system
🧊 Ice buildup on evaporator coils
🔄 Issues with the faulty compressor
🔌 Problems with the electronic control board

At this point, a service reset or an aircon repair from a licensed professional technician is your best move. Complex problems with Mitsubishi aircon models often require specialized diagnostic tools that only certified technicians possess.

Advanced DIY Troubleshooting (Following Safety Guidelines)

If you're comfortable with basic electrical work and want to try additional steps before calling a professional:

Check the metre box for any tripped safety switches beyond the main circuit breaker
Inspect the outdoor unit for debris or vegetation that might be restricting airflow
Examine drainage pipes for blockages that could trigger safety shutoffs
Test other appliances on the same circuit to rule out broader electrical issues

CAUTION: Always follow safety guidelines when working with electrical components. If you're unsure, it's best to contact a professional.

Tips for Better Indoor Air Quality and Energy Efficiency

Your Mitsubishi air conditioner does more than cool your space—it plays a crucial role in maintaining better indoor air quality. Here's how to keep your system running efficiently after a reset:

🧼 Clean air filters monthly to prevent blockages and ensure healthy indoor air
🔍 Inspect for signs of leaks or noise changes that might indicate developing issues
🛠️ Book professional maintenance every 6–12 months following manufacturer's guidelines
⚡ Use a surge protector to guard against electrical surges that can damage the control board
📖 Keep your manual handy for error codes and model-specific troubleshooting
🌡️ Set reasonable temperature differences (no more than 8°C below outdoor temperature) for energy efficiency
🕒 Use the timer function to avoid unnecessary operation when no one is home

Cost-Effective Maintenance Tips

Regular maintenance is key to avoiding issues that require resets in the first place:

Quarterly filter cleaning: Remove and wash filters with mild soap and water
Seasonal outdoor unit check: Clear debris and vegetation around the outdoor unit
Annual professional service: Have a technician inspect refrigerant levels and electrical components
Check drainage: Ensure condensate lines remain clear and free-flowing

A well-maintained Mitsubishi AC system should provide 10-15 years of reliable service, making these maintenance steps highly cost-effective in the long run.

FAQs

Where is the Mitsubishi aircon reset button located?

Most indoor units don't have a dedicated physical reset button, but the ACL button on the remote acts as the reset. Alternatively, use the breaker method described above.

Why is my Mitsubishi AC blinking after reset?

The blinking light could indicate an error code (e.g., filter needs cleaning, sensor failure). Count the number of blinks and refer to your model's manual or call for support.

How long should I wait before turning the breaker back on?

2–5 minutes is usually enough to let the system fully power down and reset internal memory.

Can I use a flat screwdriver to reset any parts of my aircon?

Some access panels might require a flat screwdriver to open for filter cleaning or inspection, but there are no screwdriver-operated reset mechanisms in typical Mitsubishi residential units.

How often should I reset my Mitsubishi air conditioner?

Resets should only be performed when troubleshooting specific issues. Regular resets are not part of normal maintenance and may indicate an underlying problem that needs professional attention.

Final Thoughts: Resetting Is Your First Line of Defense

Resetting your Mitsubishi air conditioner is one of the quickest ways to fix minor issues—especially if the unit stops cooling, lights start blinking, or the remote won't respond. By simply cutting power and restarting, you give the system a clean slate.

Regular maintenance following the manufacturer's guidelines remains the best prevention for problems.

Clean filters, proper thermostat settings, and annual professional check-ups will ensure your Mitsubishi electric air conditioner delivers reliable cooling and better indoor air quality for years to come.

If you've tried the steps above and your unit still isn't working, don't worry—help is just a call away.