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What To Do When Your Mitsubishi Mini-Split Stops Heating

What To Do When Your Mitsubishi Mini-Split Stops Heating

Understanding the Mitsubishi Mini-Split Heating System

Before we dive into troubleshooting, let's briefly discuss what a Mitsubishi mini-split system is. Unlike traditional HVAC systems that rely on ductwork to distribute air, a mini-split operates without ducts, making it a versatile heating and cooling solution for various spaces.

Consisting of an outdoor compressor unit and one or more indoor air-handling units, a Mitsubishi mini-split allows for customized climate control in individual rooms or zones. These units are renowned for their energy efficiency, quiet operation, and precise temperature regulation, making them a popular choice for Austin, Texas homeowners seeking comfort and convenience

Here's a simplified breakdown of the process:

  • Heat Pump Mode: In heating mode, the outdoor unit acts as an evaporator, absorbing heat from the outside air (even at lower temperatures) – a crucial feature for those occasional Austin winter dips. The refrigerant absorbs this heat and is compressed, raising its temperature.

  • Indoor Comfort: The hot refrigerant then travels to the indoor unit, which acts as a condenser. Here, the heat is transferred to the indoor air through the internal coil and fan, warming your living space and keeping you toasty during those cool Austin nights.

A Step-by-Step Guide to Troubleshooting When Your Mitsubishi Mini-Split Stops Heating

When your Mitsubishi Mini Split isn't performing its heating duty, a methodical approach can help pinpoint the culprit. Here's a step-by-step troubleshooting guide to get you started:

1. Verify Thermostat Settings:

Mode Check: Most thermostats offer a dedicated "Heat" mode. Ensure your thermostat is set to this mode, not "Cool" or "Auto."

Temperature Control: Double-check that your desired temperature is set higher than the current room temperature displayed on the thermostat. The system won't activate its heating function if the desired temperature is already reached.

2. Inspect the Air Filter:

A clogged air filter is a common culprit behind inefficient heating performance. A dirty filter restricts airflow, hindering the system's ability to circulate warm air throughout your space.If you suspect your air filter could be the culprit, here are some useful actions you can take

Cleaning Routine: Refer to your Mitsubishi mini-split’s owner's manual for the recommended cleaning frequency for your specific model. Generally, cleaning the air filter every two weeks during peak usage times (think those occasional cold fronts in Austin) is a good practice.

Cleaning Method: Most Mitsubishi mini-split air filters are washable. Remove the filter, gently rinse it with warm, soapy water, and allow it to dry completely before reinstalling. If the filter is excessively dirty or damaged, consider replacing it with a new one.

3. Power Supply Check:

A seemingly obvious issue, but sometimes the simplest explanations hold the key. Ensure your Mitsubishi mini-split unit is turned on at the unit itself, not just the thermostat. Additionally, check the following:

Circuit Breaker: Verify that the circuit breaker controlling the unit hasn't tripped. Reset the breaker if necessary, but if it trips repeatedly, consult a qualified electrician to diagnose a potential electrical issue.

Power Cord: Inspect the power cord for any visible damage or fraying. A compromised cord could disrupt the power supply and prevent the unit from functioning.

4. Remote Control Functionality:

The unsung hero of your comfort control system, the remote control can sometimes be the source of confusion. Here are some troubleshooting tips for your remote:

Battery Check: Dead batteries are a common cause of non-responsive remotes. Replace the batteries with fresh ones and ensure they are inserted correctly according to the remote's manual.

Remote Aim: Like a line-dancing pro at the Broken Spoke, point the remote control directly at the indoor unit's infrared receiver for optimal signal transmission.

5. Advanced Troubleshooting:

If you've meticulously followed these steps and your Mitsubishi mini-split remains uncooperative, it might be time to consider some of the more advanced troubleshooting options:

Error Codes: Some Mitsubishi mini-split models display error codes on the indoor unit when encountering specific issues. Consult your user manual to decipher the error code and identify the potential problem.

Manual Inspection: Look for any visible signs of damage on the indoor or outdoor unit. Unusual noises or leaks could also indicate a malfunction.

When to Call a Professional:

While these troubleshooting steps might resolve basic issues, some situations require the expertise of a qualified HVAC technician. Here are some indicators that professional intervention is necessary when your Mitsubishi mini-split heater stops heating:

  • No Response: Even after confirming the power supply and proper settings, the unit remains unresponsive.

  • Unusual Noises: The unit emits loud or unusual noises during operation.

  • Limited Heating Capacity: The system struggles to maintain the desired temperature despite proper settings.

  • Leaking: Any visible water leaks from the indoor or outdoor unit.

The Wright Choice for Mitsubishi Mini-Split Repair and Maintenance


Wright's currently serves Wimberley and the close surrounding areas specializing in air conditioning repair, service, and replacement of most all central heating, air conditioning, and heat pump systems.

Wright's Heating & AC Service is the only authorized Carrier® dealer in Wimberley and a Mitsubishi Diamond Contractor™ The personnel at Wright's are also experts on Ductless Inverter mini-split systems and Conventional AC, Heat, and Heat Pump Systems.

Wright's has an A+ rating with the Better Business Bureau® (BBB) and belongs to the National Association of the Self-Employed (NASE) and the National Federation of Independent Businesses (NFIB).

Contact Wright's AC and Heat today for expert Mitsubishi Mini-Split repair and maintenance. Schedule an appointment online or give us a call at 512-847-3191.

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