How to reset a MRCOOL mini split AC in 5 easy steps

MRCOOL mini splits are a popular type of ductless air conditioner used to cool or heat single rooms or spaces. Like all air conditioning units, mini splits can occasionally run into problems that require the user to reset them to the factory default settings.

Resetting a MRCOOL mini split air conditioner is usually fairly simple and may help you resolve minor issues with a unit that won’t turn on or if you need to clear error messages after a repair.

Let’s find out how you can find the reset button on your MRCOOL mini split AC and reset it if needed.

If you need any replacement parts for your MRCOOL air conditioner, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

Disclaimer: The troubleshooting information provided in this article is based on general service manuals and may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

When you should avoid resetting a MRCOOL mini split 

While factory resets can fix many basic mini split problems, there are certain situations when resetting will NOT help and may actually cause larger issues.

Avoid resetting your MRCOOL mini split if:

You recently had the unit serviced

If an HVAC technician recently repaired your unit and applied specific control settings, resetting deletes those changes. This could reintroduce the very same problems they just fixed. Always check with the technician before resetting soon after a repair or service call.

The outdoor unit isn’t running

Resetting ONLY restores indoor unit software and electronics. It doesn’t impact external parts like outdoor condenser units.

If your outdoor mini split unit doesn’t turn on, there could be larger electrical issues that resetting won’t fix. Call for professional service instead.

If you haven’t investigated an error code

Error codes typically indicate hardware malfunctions that need to be repaired by a professional HVAC technician. The E1, E3 and E5 error codes may be able to be cleared by resetting, but avoid trying to reset the unit if it’s displaying a different code.

If you reset your unit but the same errors display again shortly after, don’t reset the unit again and schedule service ASAP. Ignoring recurring error codes can cause greater damage to your unit over time.

Issues persist after the initial reset

You should only need to reset your mini split AC once to resolve software glitches or frozen controls. If any problems remain after the initial reset, then this points to a deeper system issue that needs to be checked out by an HVAC technician.

Multiple resets can also wear down electronic components faster, so you should leave further troubleshooting to the professionals in this case.

How to reset a MRCOOL mini split AC

Step 1: Find the reset button

The reset button on most MRCOOL mini split indoor units is found on the control/remote or behind the front panel, often near the air filter.

Here’s how you can access the reset button on standard wall-mounted MRCOOL units:

1. Turn off the unit with the remote control or manual power switch.
2. Remove the front panel. You may have to remove clips, screws, or hooks that hold the decorative front cover in place.
3. Find the reset button (often labeled) on the interior control board near the air filter.

Step 2: Press and hold the reset button

1. If necessary, use a small object like a paper clip or pen point to reach the reset button.
2. Press and hold the button for 3-5 seconds until your unit beeps or the lights flash. The unit should immediately power off. At this point, you can release the reset button.

Step 3: Disconnect power (if required)

Some MRCOOL units require the user to disconnect them from the power supply for 30 seconds after resetting and before restarting them. Check your model’s manual to see if this applies to your ductless AC. If so, flip the appropriate breaker or switch for 30+ seconds.

Step 4: Replace the front panel

Carefully replace the front cover and any screws or clips to reassemble the unit.

Step 5: Restore power

If you cut the power in the previous step, turn it back on now. Your unit should restart itself within a minute or two.

When to reset a MRCOOL mini split 

If the indoor unit won’t turn on

If your indoor unit won’t power on at all, a reset can help clear any software glitches.

Start by checking the power supply, breakers and fuses, then try resetting the unit if power is connected but the unit still won’t start.

If the unit won’t heat or cool correctly

Resetting the unit disables any incorrect user settings that could cause problems with heating, cooling, drying, ventilation, or fan speeds. After a reset, these functions will automatically return to the suggested factory standards.

A reset can also clear minor system faults that may lead to improper temperatures, airflow levels or excessive noise.

If you need to clear an error code

Error or fault codes typically display when your MRCOOL mini split senses internal technical problems. While resetting the unit won’t fix underlying issues that need to be repaired, it can clear error messages caused by temporary electrical, sensor, or communication failures.

If possible, note the exact error code before resetting the unit. This helps with diagnosing problems with specific parts that may need to be replaced.

Here are some examples of errors that can cleared by resetting:

E1 – Communication error between indoor and outdoor units

E3 – Malfunctioning temperature sensor

E5 – Electric control failure

Other unusual behavior

• The unit turns on or off unexpectedly
• The unit ignores the set temperature or modes
• The unit changes fan speeds randomly
• The unit displays incorrect information on the remote control
• The unit runs excessively long cooling or heating cycles

More information

Thank you for reading! We hope this guide helped you get your MRCOOL mini split AC working again.

If you have any other appliance repair needs or projects, don’t hesitate to explore our other troubleshooting guides and videos.

If you need replacement parts or some extra help with ordering them, grab your model number and head over to AppliancePartsPros.com, where you can chat with a pro, read our DIY blog and more.

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