Gas and Oil Home Heating Furnaces - Not Cooling Properly

My neighbour has a Rheem Seer10 Air conditioning unit approx 3 years old. When it first starts up it works and cools properly. After approx. 3 hours the air is not as cold as it was at first. We've cleaned it enough that you could eat off the unit. The compressor ices up. The fan works properly. He has had this problem for a couple of years but can't get anything from the dealer/installer except the bill for checking it out.

We were concerned about why it doesn't cool properly.

It worked good when it was installed. Oh, yeah! The warranty is up.

We live in Cambridge, Ontario Canada.

if the coil , filter and blower wheel are clean and the duct work is clear then you have a problem with the refrigerant charge.

I sounds like the coils are freezing up, have them get the freon level checked, if low they need the tech to find where it is leaking.

With a 3 yr old system, its not likely the indoor coil or the blower wheel, is plugged with gook but to be sure, get a flashlight and look deep inside the fins of the coil. Also you must make sure the indoor fan is up to speed (HI) for cooling and not running on low heating speed and is not shutting down prematurely. Make sure all the regfisters and returns are open including any dampers. As you can tell, I'm leaning towards an airflow problem. Too, this could be a bad overcharge problem, causing a flooded evaporator and slugging the compressor. If this is a heat pump, then this changes some things. Let us know.