DIY Maintenance for your Mini-Split System

DIY Maintenance mini split system

Keep your Mini-Split System running efficiently year after year by performing some simple, yet effective DIY maintenance services. These tasks are relatively quick and easy, but you’ll be rewarded with lower energy bills, fewer service calls to an HVAC professional, as well as consistent, year-round comfort in your home. 

A typical Mini-Split System consists of two units:  an indoor evaporator unit and an outdoor condenser unit. The two units are connected by power, refrigerant and drainage lines. In order to properly service the system yourself, you’ll need basic knowledge of these two units and at least a little DIY experience. The main thing to remember is that your system requires free and unrestricted air flow across both units—the indoor cooling cool and the outdoor condenser unit.

Before beginning any DIY maintenance on your Mini-Split System, be sure to read all the instructions below, making sure you fully understand the steps and are comfortable performing the following complex tasks. Otherwise, we recommend you contact a qualified AC technician or HVAC professional.

DIY Maintenance mini split system

Cleaning the Indoor Air Handler

●          Turn off the power to your outdoor condenser unit and all indoor air handlers (including power at the breaker box and at the outdoor unit’s shut-off box).
CAUTION: Failure to do this may result in electrocution.

●          Allow your system to rest for at least one hour before cleaning, as the units need time to return to a standing temperature.

●          Locate each indoor air handler unit and open it. Gently lift the bottom edge of the unit cover and locate the air filters (typically on top of the evaporator coil). Remove the filters and clean them by running them under a gentle spray from your kitchen sink nozzle or faucet. Sit them aside to dry. 

●          Clean the evaporator coil with a soft cloth, removing any visible dirt or dust. Keep an eye out for signs of mold and mildew around the coil or on the components. If you do see mold, contact an HVAC technician to deep-clean the coil and treat it to prevent future mold contamination.

●          Replace the air filters and close the cover. 

Maintaining your Outdoor Condenser Unit

DIY Maintenance mini split system

●          Locate the outdoor condenser unit, and remove any debris, excess vegetation or clinging vines from the area around the condenser. This will reduce the risk of fire during the drier summer months, as well as improve air flow. We suggest you clear at least two feet from the unit in all directions. 

●          Using a powerful shop vacuum with brush attachment, remove visible dirt and debris from the exterior fins. Follow this up with a gentle spray from a garden hose to remove any remaining debris. NOTE:  DO NOT use a pressure washer or heavy spray in this step—it will damage the fins. If dirt is still present on the exterior fins, use a fin-cleaning spray (found at most home improvement stores).

●          Use a fin-straightening tool or butter knife to straighten any fins that were bent during cleaning.
CAUTION: Be careful not to damage any embedded tubing located behind the fins.

●          Using a soft cloth, gently wipe away visible dirt or debris from the air conduit. If dust, dirt and debris is allowed to collect on the conduit, it will prevent air from flowing freely into your home, shortening the life of your system and driving energy bills through the roof. Plus, air conduit can develop leaks over time, so this is a good time to check for cracks and breaks. If you do find leaks, contact an HVAC professional for service.

●          If you also use your Mini-Split System for heating, be sure to check for ice and snow accumulation, removing any that you see. 

●          Make sure the condenser unit is level with the grounding pad underneath. A unit that sits askew with the pad will not perform at peak efficiency and is prone to early failure. If you notice your condenser is tipping to one side, use rot-resistant shims to level it. 

Checking the Thermostat

The last, and easiest, way to maintain your Mini-Split air conditioner is to make sure the system’s thermostat is in good working order. To do this, simply raise and lower the temperature setting until the air handler turns off and on in response to the settings. 

By regularly performing these quick and easy maintenance steps, you’ll keep your ductless Mini-Split System in peak condition, resulting in lower electric bills and a more comfortable home. We recommend following all manufacturer’s guidelines when doing any DIY service. 

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    I cleaned the filters regularly, but the fans need to clean because they are now 8 years old. All the support companies I’ve called to clean up say they don’t hold back and clean up.

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