If you live in a smaller home or an apartment, there is a chance the heating and cooling system you have in place is a ductless mini-split. These systems, which operate free of a connected duct system, are highly-efficient and do perform reliably for a long time most of the time. However, just like any other HVAC system, a ductless mini-split can have problems. If you're having problems with your system, it is best to try and diagnose the issue on your own to ensure the problem is not a simple fix.
Nothing happens when you push the control buttons.
You decide you want the heat on or you want to turn down the AC, so you go to the control panel on the unit and push the usual buttons. Nothing happens. You make sure the unit is connected to power, and the breaker isn't thrown, and still, nothing happens. If this is the problem you are having, it is highly likely that the control panel has gone bad. This panel has an electrical circuit board behind it that receives your inputs and sends relays to the system. Sometimes, the circuit board will fail before the system goes bad, but thankfully, this is an issue that can be repaired with a simple replacement by a contractor.
You turn on the heat, and no heat comes out; only cool air.
Most mini-split systems contain a heat pump that uses geothermal energy from the air outside to give you heat. If you turn on the heat and are getting only cool air, there could be a problem with the heat pump's geothermal setup. In these cases, a lot of people assume it must be too cold outside to harvest heat, but that would be a rare event unless you live in an extremely cold place. Therefore, you may have to have the geothermal setup reconfigured.
The unit is frozen over, and no air is coming out.
Just like a typical window AC, if the unit is freezing, it means the condenser is not getting enough air flow to prevent the condensation inside from freezing before it is expelled. Check the filter in the mini-split by pulling open the front panel and clean it if necessary. It is also a good idea to thoroughly clean the outside of the unit if it has amassed a buildup of dust and debris. Allow the ice to melt before turning the unit back on. If the problem persists, there could be an issue with a weakened ventilation fan inside the unit.
For more information, contact your local HVAC contractor.