I don't know the name of the pipe. There is one thin and thick pipe. The thin one gets hot and the thick one I believe is supposed to be cold when the unit is on.
I have about 11 years split system in Dallas. Coil is in the attic and condensor is outside. The pipe used to be cold when A/C was on. When my pipe was nailed by a roofer and fixed last year, I asked the A/C guy why the pipe was not cold any more and he said it'd be still okay. The house was cooling anyway. I survied last year summer with the unit. It still took longer to cool the house though. The temp difference I heard is 15 degree which was excellent per him.
This year, the pipe is still not cold and it takes a lot longer to cool the house and I am worried. There is no condensation whatsoever when my the other unit for upstair has condensation and the pipe is very cold.
Is it something I should call soemeone to check? The temp difference when outside was 90 was about 12-13 degree in the way I measured. The coil inside was replaced 2 years ago and outside unit is about 11 year old carrier 3.5 ton for 3500 sq house. I have another 4 ton for upstairs as well.