What causes the evaporator to freeze?

Answer 1

The evaporator may be dirty or the condenser(outside unit) may be dirty. You may be low on "freon", indicates a possible leak. Check the filter. ---------------------------------------------------------------------------------------------------- If you're asking why the 'outdoor' part freezes, it's too cool outdoors. You should never run a house central A/C when the outdoor temperature is below 60 degrees F. Professionals will tell you that you can blow out a compressor this way. Big $$$$. You may be asking why there's a part in your furnace (that has part of the central A/C inside) that freezes over with ice in the summer. Your first clue will be that the house gradually grows very warm even though the A/C is running, and it worked fine until now. If the indoor air is too hot and damp when you turn on the A/C, you can overwhelm the system's ability to move heat out of your home. Instead of collecting moisture at the heat exchanger inside your furnace and using gravity or a small pump to move the water to a drain or outdoors, the water freezes right on the heat exchanger. The ice acts as an insulator, continues to build and the house will remain warm. This can cause expensive damage as the ice grows too big for the area around it. Switch the thermostat to heat (furnace) instead of cool and raise the temperature setting for about 5 minutes and the ice should all melt, then you can switch back to cooling. Since you've already removed much of the moisture in the house, you'll probably be fine, and the few minutes the furnace was running won't even be noticed. Chazzzman ------------------------------------------------------------------------------------------------------