Gas and Oil Home Heating Furnaces - FREEZING A/C UNIT

I HAVE NOTICED THAT MY AIR EXCHANGER IN THE ATTIC FOR THE A/C IS CONSTANTLY FREEZING. I HAVE THE AIR TEMP SET AT 72. THE A/C LINE OUTSIDE IS ALSO FREEZING. HELP

for one hour.LEAVE FAN RUNNING TO COMPLETELY DEFROST COIL.Check for plugged filter.Once you have COMPLETELY defrosted coil MAKE sure you have air flow.Blower motor may not be running.Does it run when you place a/c on?How dirty is air exchanger coils and fins?PDF

I have done that. I opened the attic air exchanger and cleaned it with a hose using reverse flow (as I did in the Navy). It cooled a little better but it is still freezing. The temp is set at 74-76 degrees. The only thing I can think of is the fan is dirty and not pulling enough air, and the heat exchanger that is closest to the outflow from the fan is also dirty. This one is very difficult to get to, but I will spend all day working on it. Do you have any more suggestions that might work. I closed most of my vents in the first floor celling so the forced air would channel upstairs. Only noticed a slight improvement. No air ducts are dirty and the filter is cleaned alot.
Dennis

an air compressor you can blow most of the stuff out.YES it will be messy,but 120 psi air can remove a lot of stuff in areas you can not reach.Make sure they supply you with a wand with a trigger on it.Most times the wand is a foot long to reach hard to get at areas.REMEMBER---SAFETY GLASSES!!!!!Make sure you clean each blade of squirrel cage.I spent 6 years in the NAVY. "SILENT SERVICE"..Did tours on the USS TUSK SS 426 a diesel submarine,and the USS BATFISH SSN 681 a fast attack nuke.Were you a "skimmer"?I was an auxilaryman forward,a fancy term for Machinist Mate.Hope I have been of some help.Clean everything as much as possible.Give us a holler back if need be."REMEMBER,IT'S JUST NOT A JOB,IT'S AN ADVENTURE!!!!!!!!!!PDF