How far into AC outside unit should cold line be insulated?

D107

See photo. I'd guess I should insulate at least the remaining 18 inches or so of the line--not sure why that wasn't done in the first place. The line continues inside the unit but I've never seen that insulated. Is Armaflex recommended or should I splurge and get the kind that's UV resistant? I saw some tech on youtube put strips of aluminum foil tape to protect from UV and heat but not sure about that. Anyone guess what size the insulation would be for that line. 5/8? 7/8?

EBEBRATT-Ed

Measure the outside diameter of the tubing. Then buy armaflex with that Inside diameter. Armaflex usually comes with 3/8" or 1/2" wall thickness.

They make uv protectant "paint" for the armaflex. Standard practice is to insulate up to the suction shut off valve. You can insulate up to the compressor if you want to.

unclejohn

Don't worry about insulating inside the cabinet. It's either 7/8 or 3/4 either will work. Personally I'd won't even bother with it.

ChrisJ

I used 3/4" thick Armaflex on my suction line.
It's nice............but it caused headaches with some things, like the lineset cover sizing.

I used standard 3/8" thick on the liquid line.

D107

Why would insulation be used on the hot line? That's supposed to shed the heat yes? Unless outside air temp is hotter than that line....(?)

ChrisJ

David107 said:

Why would insulation be used on the hot line? That's supposed to shed the heat yes? Unless outside air temp is hotter than that line....(?)

I used in areas exposed to direct sun, and more importantly in the attic where my air handler is. The liquid line's job isn't to shed heat, that's the condenser's job, but it won't hurt. But it is important that the line doesn't increase in temperature after leaving the condenser.