Can anyone help? I purchased a new Goodman 2.5 ton split heat pump system 2 weeks ago. The other night it gone down to 20 degrees and the outside unit froze up like a solid block of ice. The unit kept running constantly but wasn't keeping the right temperature, it was not defrosting. I called service and was told to put the unit on Emergency heat for the night which turned off the outside unit. The next morning after the sun warmed up the air the ice melted in the unit. I turned the unit back on and it run very well and began defrosting like it should? I had the serviceman check the freon and he said it was fine had the right amount. He has no idea what caused the unit to freeze up. Any ideas, what if this happens again?