Hey ! The coolant line to the furnace has about 8 inches of bare copper pipe and ice freezes on the outside surface.
The outside unit copper pipe was missing some insulation (FIXED) and it had solid ice on it too.
Today, reached 98DegF and the air output temp at the register was running 61-65 DegF. Pretty decent I guess..
G
Freeze-ups usually indicate it is large of a system. It is cooling too fast, so it runs too little, and this prevents the humidity from being taken out of the air. You could probably add an extra dehumidifier in the house and this could help. I would also run ceiling fans to help circulate the air.
I have a large house like you have and have a 5 ton and a 2 ton. The 5 ton is a Trane (put in in 2006) that takes care of most of the house and the 2 ton is a Carrier that covers the bedrooms at night. Both are good systems, but I might replace the Carrier with a Trane if it ever breaks down. When I put in the Trane I replaced the entire system with new including all of the lines and the condenser because I didn’t want to be dealing with pinhole leaks.
Sorry... I meant to say that I think you have too large of a system installed now.
Also check your drains. If it is pulling out water, it needs to go outside the house by a drain. If water just sits in the tray inside your house, it causes problems with both comfort and freezups due to excess humidity.