Not Boat related--Welding copper to Aluminum?

[1BIGJIM]

Its kind of boat related because this is taking away from my boating funds

I have a five ½ year old Trane Air Conditioner that sprung a leak. The repairman told me they made a fix. A flare fitting with a compression ring. Ok the first one they put on looked like stainless steel. I ask them if they got the repair kit at Home Depot. I was told it was special because the properties in the two different metals. Ya right.
Anyway they cannot get the fitting to work. I could have told them that when they tried to install it. The aluminum is porous I don’t know how they think a compressing ring would seal. Well it did not. So they left me another day with out AC and was going to call Trane to see if there is anything else left to do.

You can see the original joint at the bottom, they welded the copper to aluminum at the factory. You can also see the other line right behind it that has copper connected to aluminum.

So what is the trick?

Free beer

There answer is to buy a new unit and A-coil.

I need the 3k to fix my outdrive

[c_deezy]

Is it really welded or was it brazed/soldered together?

I would say possibly braze the joint together, then sleeve it with a size bigger pipe then solder that on a few inches on each side of the repair.

If you try that remember to put the bigger pipe on before making the initial repair!

[Griff]

Good thing its been cool out. Tomorrow's gonna be 80* though.

That looks like POS rig job with the comp rings.

If they are gonna try that, then why not use a flare on both tubing ends and get the proper flare fitting. Not sure if that will work either though depending on the pressure. Probably needs to be soldered as stated above.

[Planetwarmer]

If you put two dissimilar metals together it will cause something called galvanic corrosion. A common example of this is when Howie the homeowner does their own plumbing. People will often put together copper pipes with steel pipes without a proper connection causing serious corrosion and very premature pipe failure. If you soldier those two metals in your AC unit together, you will in fact have a problem in the future of galvanic action (corrosion). Contact a knowledgeable HVAC -PARTS dealer-, they will guide you in the right direction. A repairman will want to fix it for you. Some times they are reluctant to give out free advice.

[Chris Sunkin]

I know a little about HVAC but alot about fluid power plumbing. In FP, they do use some compression fittings and I don't like them, but we're dealing with alot less pressure here.

Had they tried this fix on new equipment, they may have had a better chance. The surface corrosion where the collet ring binds to the tube exterior is why it leaks. If it were me, I'd see if they could use a flare on the aluminum tube. I'm assuming it's malleable and it may flare. It may be so old and brittle that it may just split too. The advantage of the flare is that it will use the inside of the aluminum tube to seal- which hasn't corroded.

I'd also start shopping for a new supplier. I just had mine done and it was just over a grand.

[1BIGJIM]

Originally Posted by Planetwarmer

If you soldier those two metals in your AC unit together, you will in fact have a problem in the future of galvanic action (corrosion).

If that is true, how did they connect the copper and aluminum at the factory? If you zoom in on the picture you can see the joint on the other copper and aluminum connection.
There should not be any corrosion they peeled back the rubber sleeve over the top of the aluminum.

I have not welded aluminum since High School. I remember it had to be very clean. And I did not think you could braze aluminum or for that aluminum to copper.

I guess that is why I only weld steel today..

Maybe I should learn how to weld aluminum again then I could fix my out drive problem posted in that forum.

[Chris Sunkin]

Shot an e-mail to a pal in the biz

http://www.thermadyne.com/

These people ave a product called Turbotorch Viper Aluminum repair kit. For fixing evaporators & such. He says it will solder coper to aluminum. Kit comes with special solder & flux.

[Planetwarmer]

Originally Posted by 1BIGJIM

If that is true, how did they connect the copper and aluminum at the factory? If you zoom in on the picture you can see the joint on the other copper and aluminum connection.
There should not be any corrosion they peeled back the rubber sleeve over the top of the aluminum.

I have not welded aluminum since High School. I remember it had to be very clean. And I did not think you could braze aluminum or for that aluminum to copper.

I guess that is why I only weld steel today..

Maybe I should learn how to weld aluminum again then I could fix my out drive problem posted in that forum.

I dont know. They probably used the force!

[320es]

I had to do the same thing at my old house. I used silver solder and a sleeve of copper tubing, it lasted at least unitl I moved ~ 3 years. Like all soldering/ brazing just make sure everything is clean.

[1BIGJIM]

Thanks guys.

I am not giving up yet! The service guy told me yesterday that Trane will replace the condenser under waranty.
How much labor I don't know that yet. Its like anything else they get you one way or another.