May 5, 2024

Mini-splits have become popular among property owners because of their high energy efficiency and easy installation. They provide customized comfort, allowing you to set individual temperatures in different rooms. Like other HVAC systems, however, mini-splits can develop issues over time. Let’s explore how mini-splits work and the four most common problems you can anticipate with your system.

Understanding Mini-Splits

Mini-splits are heating, ventilation, and air conditioning (HVAC) systems. Unlike central systems, they provide both heating and cooling functions. They are composed of two units, an indoor and outdoor component, that are connected by a conduit running through a small hole in a wall. During installation, the technician drills a hole through the wall, about three inches wide. They pass the conduit, which houses the power and communication cable, copper tubing, and a condensation line, through this opening.

The indoor unit is often mounted on walls or ceilings. It houses the evaporator coils, filters, and blowers. The outdoor unit features a compressor, condenser coils, and a fan. In cooling mode, the refrigerant absorbs heat from the warm air as it flows on the coils. It then transfers the warmth to the outdoor unit for release to the environment. On cold days, heat is absorbed from the outdoor air and is transferred to the indoor spaces.

Since they do not have extensive ductwork, mini-splits prevent energy loss. Ducted HVAC systems lose up to 40% of energy through air ducts. This happens when there are leaks or the duct is not adequately insulated and runs in unconditioned spaces.

Troubleshooting Common Mini-Split Problems

Here are some common issues you can expect and their possible solutions.

1. System Won’t Start

When your system fails to turn on, it can be a source of panic and discomfort. Several issues, including a lack of power supply to the units, can cause the system to not start. A circuit breaker might have tripped, cutting off the power supply to the system. You also could be experiencing a power outage or faulty electrical systems. Compromised electrical wiring, either because of general wear and tear or old age, can interrupt the power supply to the system. Due to the high risk of electrocution when addressing electrical issues, you need to hire a professional when you suspect faulty wiring so that they can safely upgrade or repair the system.

If there is a power supply to the system and it still doesn’t turn on, check the remote batteries, as they may have died. Alternatively, you can inspect the condition of the sensors. Mini-splits have sensors in the indoor unit that monitor indoor temperatures so the system can adjust them accordingly. The sensor can malfunction because of dirt or misalignment. If dirty, wipe gently with a dry cloth and ensure it is in the correct location according to the manufacturer’s instructions. If there are physical signs of damage, consider asking for professional help.

Your system may also fail to turn on when the thermostat is faulty. This can occur when there is poor or no communication between the thermostat and the mini-split. It can also be due to incorrect temperature settings. For instance, the system will not turn on when set to heat mode during the summer. Ensure it is set to heat mode during cold days and cool mode on hot days.

2. Refrigerant Leaks

Refrigerator leaks are the most common mini-split problems. The refrigerant running through the conduit can leak if there are holes in the line. These can occur when the copper walls corrode. The joints and connections on the system can also weaken, allowing the refrigerant to leak. Improper system installation or defects due to manufacturer errors can also cause the problem.

Refrigerants are in gaseous form and you might not notice them visually when there is a leak. You may realize there are leaks by hearing hissing sounds coming from the system. This is produced as the pressurized refrigerant escapes from the system. Jiggling sounds when the unit operates with inadequate refrigerant are also common signs of a leak.

Low refrigerant levels contribute to high energy bills. The system will be unable to absorb sufficient heat without the proper amounts of refrigerant. The house remains warm in cooling mode while there is inadequate heating in heat mode. The mini-split thus has to overwork to meet the desired temperature, leading to high energy consumption.

The evaporator coils can also freeze. While this can be caused by other problems, such as inadequate airflow, inadequate refrigerators are a major cause of freezing coils. Without the right amounts to absorb heat, moisture can condense on the coils when indoor air flows over them. Over time, the condensation can freeze on the cold surface, leading to ice formations.

Refrigerants are highly toxic, which is why you should contact a professional HVAC technician to resolve the problem. After repairing the source of the leak, they will refill the refrigerant to the recommended levels.

3. Leaking Water

Issues with the condensate line can lead to water leaks. Mini-splits have a drain line that directs condensate water from the system. This is the water collected when air moisture condenses on the evaporator coils. In some systems, the water flows out by gravity while others rely on a pump to force the water out.

Mold and algae can grow within the line because of favorable conditions created by moisture and warmth. They can accumulate and obstruct water flow. If the drain line is clogged or blocked, the water backs up and can leak inside the house. The problem may also occur when the unit is not installed at the proper level, disrupting proper drainage. The system’s electrical parts can be damaged if they come into contact with the water. This affects their performance and increases the risk of electrical hazards and damage to the unit. Your mini-split system might suddenly fail to start or shut off.

A technician can inspect the system and ensure that a tilt is not interfering with free water movement. They will also check the seal between the indoor unit and the wall for signs of damage where the leak is occurring. If the cause is a blocked drain, they can remove the dirt buildup to allow water to flow freely again.

4. Inadequate Heating or Cooling

Your mini-split may sometimes operate but fail to produce the expected heating or cooling effects. This is often caused by dirty air filters. Mini-splits have filters that trap dirt for improved indoor air quality. When the trapped particles accumulate, they will restrict airflow and prevent the system from correctly controlling the temperatures.

Insufficient heating or cooling can also be linked to incorrect thermostat settings, inadequate refrigerant levels, or a malfunctioning compressor. The mini-split relies heavily on the compressor as it is responsible for pressurizing the refrigerant. When faulty, this component may make weird noises, including grinding, squealing, and rattling, which often indicate mechanical wear. An HVAC professional can identify the underlying cause of poor heating and cooling. They can repair or replace the compressor and recommend cleaning or changing dirty air filters.

A mini-split is a significant investment toward a comfortable and energy-efficient home. When one or more of these problems occur, they can disrupt its functioning. Our professionals at Scott-Lee Heating Company can quickly respond to your call when your mini-split malfunctions and solve the problem. Besides mini-split repair, we also offer heating and cooling systems installation, maintenance, and replacement services for commercial and residential properties. Our services are available throughout St. Louis and the surrounding areas. Additionally, we offer indoor air quality services.

Contact us today at Scott-Lee Heating Company to book an appointment with our qualified technicians.