Can I perform Basic Maintenance?

You can start by keeping the external unit clean, by simply wiping it down every few weeks and making sure no leaves get caught up near it. 

You also need to clean the return air filters (internal unit), especially if the unit is exposed to a lot of dust. This can cause your unit to ice up if left to accumulate. 

The same applies to the external condenser fins, which needs to be regularly cleaned. 

Another easy spot of maintenance is to keep the drain outlet coming from the external condenser clean. This is normally a clear plastic hose that hangs out of the bottom of the unit.