Noticed a problem about an hour ago, air worked great today, came home and it was warm inside. No circulation so checked, vents, air filter and blower to see if it was operating correctly. All checked out, removed cover to evaporator and the entire unit is covered in ice. turned unit off and removed cover to evaporator and entire inside is iced also, i'm waiting for it to thaw out to clean it, could it be because of it being dirty or do i have a leak? thanks.

 

Though being low in refrigerant is a possibility, other causes should be considered fas well.

- low airflow across the coil could cause this. Maybe you are using a filter that is too restrictive (dirty, and/or of too high an efficiency, and/or insufficient returns, and/or too low a speed selected for the inside blower)

- thermostat setpoint too low, which in turn instructs the unit not to stop. On a very hot & humid day, this could cause what you report

- marginally low refrigerant charge to the point that the temperature of the coil is below the freezing point of water (coil then ices up). Only with proper hvac/r tools one can determine this.

- extremely dirty evaporator coil


In lieu of removing the cover door to the evaporator coil and patiently waiting for it to thaw (which could really test your patience), next time turn the heat ON and raise the thermostat setpoint albeit just for a couple of minutes, just until the ice melts (you'll know when the ice is gone by the air that will again start coming off the registers

 

Thats a good idea, about using the heat to melt the ice. The evaporator is thawed and looks cosmetically clean. I have always had, in my opinion real crappy air flow. Two years ago i had a hvac guy out and he said that my blower was on high. When i get home im gonna put the cover back on and run just the fan with a new filter installed, It was kinda dirty, and see where im at. If air flow is still bad ill check the blower motor itself and squirrel cage. Thanks for the reply