I'm closing in a room that has a chase located next to the chimney. I
want to run lines for a future central air system while the wall is
open. There's a crawl space below, marginal access on the second floor
and good access in the attic where the air handler will be located. I
picked up a 50' 3/4" & 3/8" line set which will work with the
anticipated 2 or 2.5 ton 2nd floor load.

My questions:
- I don't see how I'll be able to run the line without having at least
one or two cuts/couplings. I've read silver brazing is better than
sweating the joints. How critical is the difference?

- Is flux a problem with making connections in a refrigerant line?
Alternatives?

- I'll be pulling a 12/3 line for the unit and to provide an additional
circuit in the attic. What wire should I pull for the AC controls?

- I've never pulled such a large line. With electrical I use a fish
tape. Can I use that to help pull the insulated copper? Any tricks to
keep the insulation from hanging up and getting ripped?

Thanks.

R