Mini-splits are HVAC systems that can have multiple indoor units. Those indoor units, or heads, provide cooling and perhaps heating to individual zones. That means that these systems don’t require ducts. It also means that there’s additional equipment that can develop problems.
Let’s explore the signs that your mini-split is in trouble and needs immediate help. If you notice these signs, turn your mini-split off, if applicable, and call an HVAC company for repair.
1. Mini-Split Won’t Turn On
Is it the entire system that won’t turn on or just one head? A power issue is a common culprit when it’s the entire system. You should check both the circuit breaker for the system and the outdoor HVAC disconnect switch. If it is a tripped circuit breaker, you can reset it and try again. If it trips again, don’t reset it multiple times. That suggests a serious problem with the outdoor condenser pump. It can also be a refrigerant leak or that the system’s electronic control board has malfunctioned or failed.
If you experience a problem with one head, make sure it’s not just an issue with the remote. Can you turn it on manually? If so, it may just be bad batteries or a pairing issue. If you can’t, check the filter. A congested filter could obstruct the blower’s functionality. Beyond that, there is a wide range of potential issues, including the thermostat or other electronics or a problem with drainage.
2. Increased Electricity Costs
Modern mini-splits are highly energy efficient, but that efficiency is one of the first things to go when there’s a problem. That’s why we encourage our customers to monitor their energy usage, particularly during the cooling and heating seasons. An increasingly common mini-split feature is a smart thermostat with energy monitoring.
If you have this feature, you won’t need to track your usage. The system will do it for you and can alert you to spikes as they happen. An isolated spike isn’t cause for concern. A pattern suggests a problem. It could be as simple as needing to swap out the filter or clean the coils. It could also indicate a more serious issue, such as a condenser pump that we’ll need to break down and rebuild.
3. Weak Airflow or Air That’s Too Warm or Too Cool
Are you experiencing weak airflow from all heads or just one? If it’s just one, then it’s most likely a clogged filter or some other local obstruction. The blowers in mini-splits are highly sensitive to increased static air pressure. It could also be a problem with the blower itself. If the issue is more widespread, then it’s most likely a problem with the outdoor unit.
Perhaps there are too many leaves and other debris obstructing airflow. The problem could also be with the condenser pump or refrigerant system. If an individual unit is blowing air that’s too cool or too warm, it’s a problem with the thermostat or evaporator coil. If it’s the entire system, it’s probably a problem with the condenser unit.
4. An Iced-Up Outdoor Unit
Airflow obstruction is the most common reason a mini-split will freeze over. In a traditional air conditioner or heat pump setup, it could be leaves and other debris. If you have a VRF and are using it for heat in winter, it can be the front and even rear grille freezing over.
In either case, the airflow restriction interferes with the condenser coil transferring heat energy. If this is happening in summer and you have the option, keep the system on, turn the AC off, and keep the fan on. This will start the thawing process.
5. Short Cycling
Turning on and off too frequently is a serious problem. Left unchecked, it can lead to significant further damage. If you’ve isolated the problem to a single head, the unit is probably overheating. Maybe the filter has clogged or there’s a thermostat malfunction. Sometimes, it’s not overheating but just a faulty thermostat. If the entire system is short cycling, it’s the outdoor unit, and there is a wide range of possibilities. It could be the electrical, refrigerant, or condenser systems.
6. Excess Condensation
You can experience excess moisture either around the outdoor unit or from one of the indoor units. It usually means that there’s a problem with one or more of the condensate drain lines. Those run from each indoor unit to outside the home. It’s how the system drains moisture from the evaporator coils.
The likeliest problem is that one or more of the lines have clogged and need to be cleared. If one or more of your units need a pump, it could be pump failure. If you have a leak indoors, it likely means a wet switch has failed as well. Put something below the problematic unit in order to catch that water.
7. Bad Smells
When a mini-split is functioning well, the air coming from it should smell crisp. If the air has a noticeable odor, there’s something wrong. Biological growth can actually form on the evaporator coils over time. This can give off a musty odor or other funky smells.
Putting the system in dry mode can help alleviate the problem, but we probably need to clean that coil thoroughly. If you notice any type of burning smell, that suggests a serious issue with either the wiring or one of the electrical components. If you notice a sweet smell, that can indicate a leak in the refrigerant line inside the indoor unit.
8. Strange and Loud Noises
If you hear a loud banging noise coming from the outdoor unit, this is what we call a hard start. Excessive vibration and a tripped circuit breaker may also accompany it. This indicates a problem with the condenser pump, and it’s very important that you stop using the system and call for help. It could be the difference between a pump that needs a new ball bearing and one that we have to replace.
Inside, you may hear an occasional pop or crack when you’re near a unit. That usually isn’t anything to worry about too much, but there are sounds you shouldn’t ignore. A hum or buzz is not normal and comes either from the wires or an electrical component. Whistling suggests an airflow problem. Squealing suggests a problem with the blower, and rattling probably means that a part is loose.
Do You Need Mini-Split Repair in Portland?
If you need a mini-split repair, Specialty Heating & Cooling LLC is here to help. We have decades of experience serving homeowners and businesses throughout Portland and the surrounding areas. Our HVAC technicians also install, service, and maintain furnaces, heat pumps, air conditioners, and ductless mini-splits. We replace air filters, clean and seal ducts, and install and service whole-house air purifiers. Our team also installs and services tank and tankless water heaters and standby generators. If you’d like to learn more about our products and services or want to schedule an appointment, call today or contact us online.
