When i put my air conditioner on low cool with a low cool setting it builds up a lot of water on the coils?

Question

After 4 days it freezes , but when i put it on high cool with a high temp setting the coils stay cold but dry and it does not freeze is there a reason for this?

Answer 1

High fan speeds are for fast cooling, like in your car. Low speeds remove water more and can cause the unit to freeze up since the air is not pushed far from the unit. Try placing a floor fan in front of the a/c to move the air far away from it. The thermostat if set too cold will cause this problem too, but the fan would help a bunch just run on lowest setting.  

Answer 2

The less air delivered across the coil,the lower the suction pressure and the colder the coil.The coil being well below the dewpoint temp of the air will collect even more moisture from the surrounding air than it would normally when the fan is on high and the water will eventually freeze.

The liquid refrigerant is making its way further down the evaporator coil because it's not being evaporated fast enough because the airflow(heat) is reduced across the coil.

The suction vapor density changes with pressure.

When you are running the fan on low speed that is creating low evaporator loading causing a small amount of liquid to be boiled to a vapor.The vapor density is very light,causing the suction pressure to be low.I wouldn't run it this way all the time.just for a couple of hours at a time.Good luck.