Heating, Air Conditioning, Fridge, HVAC/A/C Compressor conduits


Hello Joe,

This is related to a question you answered for me before (listed below). My home A/C unit outside (compressor) has the 2 copper conduits/tubes/thin pipes that go from the compressor to the inside the house. The one that is insulated (I think it sends the cold gas out of the compressor, is insulated only the part outside the compressor, but there's part of it that goes inside the unit.
Shouldn't it be better if that part was also insulated?

The insulation stops where the pipe gets into the unit, there's a gas valve/small faucet on the pipe, and the valve and the rest of the pipe that's not insulated are always wet. It feels like part of the insulation has also condensed water inside. This is in Fort Lauderdale, FL (80 degrees F outside)
Is it normal for the pipe to be wet?

Thank you in advance,



Previous question:

My home A/C is a common residential one, it has the blower indoors and the compressor unit outdoors. My questio is about the unit that is outdoors. It has 2 metal (copper?) tubes that go inside the house: one carries cold gas to the inside and the other carries hot gas out, back to the unit. Right where these 2 pipes go inside the metal case of the copressor,each tube has a small cap on the top with an hexagonal shape, like a screw nut. It's like a tiny faucet or valve that you can open and close by turning it to the right to tighten or to the left to open it (get the idea?)

I was doing some garden work around the A/C unit, and I accidentally touched the top of the valve, and noticed it was "lose" I mean, it wasn't completely open nor closed, but in the middle. I donno what those are for, and I don't know if I should tighten it closed or open it completely. How should these be set for normal operation? Thanks in advance.

Best regards,


The pipe that is cold is insulated because if it was not it would drip condensation all along it's path, the parts that go into the inside and outside units can drip becuse they  drip into a drip pan.
insulating these parts dosent improve the efficency.

Heating, Air Conditioning, Fridge, HVAC

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Jim Barnhart


Fifty + years conditioning the air.


Answer questions about , residential and commercial. Answer questions about sheet metal fabrication. Fifty years plus experience. No answers for oil equipment, No answers for kitchen appliances, No answers for laundry appliances, I don't specialize in one particular area of the HVAC area, I'm more of a General Practitioner, Limited in refrigeration/

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