2 things can cause this problem. You may have a clogged condensate drain. Simple fix is to cut the PVC and use compressed air to blow through the drain. Your coil could be freezing up and when it thaws the water runs off the coil and lands in the return. If your coil is freezing you may be low on refrigerant or you have a dirty coil or filter.
If you are experiencing freezing on your air handler coil, you may want to check the freon charge to determine if it is correct. Assuming that your thermostat is operating properly, reduced air flow can also cause freezing. Check your filters and other possible blockages such as dirt on the interior coil.
the indoor unit will freeze when there is low air flow due to a dirty filter,dirty coil, fan not spinning, or the a/c unit could be low on refrigerant charge.
its low on freon have it charged
You mean ac coil, the secondary coil, of a transformer? Then for the purpose of rectification, that is , for changing ac into dc, a diode is connected in series with the secondary coil of the transformer.
The coil is inside. Check to see if the filter is dirty as well. To clean the coil you must remove the front panel to the evap coil. If you have a flat coil you must slide the coil out to clean it. If you have an A coil, take off the plate on the front of the coil and you should be able to visually inspect the coil. It is important that you do not mash the dirt into the coil fins.
I would look at the coil to see if it was freezing up. You say it's only 10 MO old . I would call the AC Co back for a warranty check.
The coil are responsible for transferring of cool air trough the unit
Low on refrigerant or not enough air getting across the coil.
My air unit was freezing up i took a brush very carefully and cleaned the A coil and washed it out it fixed my problem.
The evaporator coil is probably freezing up which will restrict airflow.
Call a ac repair man if the central air is freezing up. It more then likely is the coils are clogged which they have special chemicals to clean or it needs more Freon.