I am in the process of replacing my 17 year old, no name 5 ton central air unit. The air handler is in the attic. I had planned on using the same line set since the unit unit will also be using the r-22 refigrant.

One dealer had a problem with my current line set. The current size pipe for the 5 ton unit is 7/8 in. He is telling me that it should 1 1/8 in. He wants to replace the entire line set. All the other dealers tell me the current piping is OK.

I would appreciate any comments on if the existing piping is OK