proper way to connect copper tubing to aluminum?

[moyerboy2]

working on an old GE RTU that I did a compressor replacement on and the line going from the roto lock fitting into the evaporator coil broke loose. Was wondering if any one had any insite on repairing the copper line going to the aluminum coil. If it was just copper I could braze it but being copper to aluminum poses a tricky situation. Any help would be greatly appreciated. thanks in advance!!

[mrhvacmechanic]

Your supply house should have some type of solder to do the job. It's been a while since I have done a repair like that. I think HARRIS the manufacturer of various solders makes a kit for it.

The only suggestion I have is not to over heat when doing the procedure. You may know the Aluminum will melt if you heat it too much. Keep ypur distance with your tourch flame to control you temprature.

[GreenDude]

If the copper and aluminum are both 3/8", Trane makes a coupling designed for just this repair. It crimps the aluminum on one side and the copper on the other. You can get it at a Trane parts store for sure, though others may sell it as well.

[t527ed]

flare fitting......;)

[esdd]

Harris stay bright 8 and the black flux for aluminum, or an uniweld aluminum solder kit ( the one with the little bottle of honey colored flux ). both work great just be careful of the heat.

[moyerboy2]

Thank you all for the info. I really appreciate it going to try and solder it first if that don't work maybe then try a flare.

[marvin]

have done many of these repairs & the flare is the only one that has held
up over the long run for me. carrier used to have a coupling that you had to
heat & when the end started to change color you pulled the heat back &
let it cool & procede with repair. some where i still have some of those laying around but i think carrier discontinued those.

[Coolmaniac]

Didn't those things have epoxy inside? Years back, had a guy from an independent metal lab come to the company to demonstrate their new solder that did copper to aluminum. He brazed some and brought a pepsi can with a piece of copper sweated on the bottom, it was beautiful. The senior tech argued that if it had oil passed through it, it wouldn't work, and challenged the guy to fix one he knew of. They agreed if they couldn't fix it, they'd buy the new coil for the customer. End result, customer got a free coil.

[Airmechanical]

use the flare fitting!



.

[superfittertech]

use the flare fitting!



.

like he said.
if the aluminum coil has oil in it and it most likely does, then the solder won't hold for long.

[berg2666]

flare fitting......;)

DITTO