Our Lennox 13ACD is not blowing cold air periodically. I turn the unit off for several hours and then it begins to work again. The problem seems to be getting worse. Any advice? Additionally, when I look at the pipe going from the AC unit to the house, the area closest to the unit is covered in frost (this may have always been frosty because I never paid attention prior to the problem).

Pipes shouldn`t be frosted,1st- make sure the filter is clean
2nd-when it seems to not be working, check and make sure the blower in your airhandler is working
This is pretty much all you can do,it is now time to call a hvac tech ,you could be low on refrigerant(freon)

Our Lennox 13ACD is not blowing cold air periodically. I turn the unit off for several hours and then it begins to work again. The problem seems to be getting worse. Any advice? Additionally, when I look at the pipe going from the AC unit to the house, the area closest to the unit is covered in frost (this may have always been frosty because I never paid attention prior to the problem).

Your Lennox goodie sheet


http://0190acd.netsolhost.com/manuals/13ACD_Series.pdf