Hole in copper line

Discussion in 'HVAC' started by Speedbump, Aug 17, 2010.

  1. Aug 17, 2010 #1

    Speedbump

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    In the process of pulling a wire off the contactor of a Goodman mini split which has 115Volt control wiring, the spade connector hit a copper tube and punched an electrical hole in it. Naturally the Freon (or what ever they call it these days) left the system.

    The question is, how do you solder the hole shut? I've always heard that silver solder was used for A/C units. I have soldered a lot of copper plumbing back in the day and done a lot of circuit board soldering, but silver soldering is something I'm gonna need help with.

    Can somebody point me in the right direction?

    If we get this straightened out, then maybe I can start a new thread about the reversing valve that doesn't reverse anymore.

    Thanks in advance...
     
  2. Aug 17, 2010 #2

    kok328

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    You are going to have to braze it with silver rod. These lines can see 300psi.
     
  3. Aug 18, 2010 #3

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    Can you give me some hints on how to do the silver solder thing. I've never done it before.
     
  4. Aug 18, 2010 #4

    kok328

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    It's basically just like soldering or more like stick welding. You'll need a Oxy-Acetylene Welding & Brazing torch and some silver rod. For complete and accurate steps, you may google "HVAC Oxy-Acetylene brazing". However, being that all the freon has left your system, your going to need someone to perform evac and recharge procedures and for them to braze a small hole before doing so really shouldn't add to the cost of the recharge. It might be better just to let the HVAC tech take care of that for you.
    Good Luck.
     
  5. Aug 18, 2010 #5

    budro

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    assuming you have a acetylene/oxygen set i would probably get a little extra copper and practice on it. i know it is expensive but if you have some or know someone with some extra tubing and are determined to do it yourself that might be a good idea. if you are not comfortable with this type of torch get a pro to do it even though it won't take him five minutes. if not done properly you can easily blow a large hole in the pipe. with this type of torch you can't just put the flame to the copper and heat it up like a propane torch. i believe there are several thousands of degrees of heat difference between propane and a/o torches. you can quickly damage your body and your wallet here. be safe. thanks, buddy
     
  6. Aug 18, 2010 #6

    budro

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    kok328 is right on target. the tech performing the other tasks is going to be your brazing pro. best to let him handle it. thanks, buddy
     
  7. Aug 18, 2010 #7

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    The guy that will vacuum the lines and put in the new freon is a friend of mine, but I'm not sure he has ever done this before.

    I do have Oxy/Acetylene torches and know how to use them. I guess a Turbo torch isn't hot enough then... Right?

    Using a silver stick, do you need any kind of flux or acid or do you just clean the copper like you would to do a plumbing repair?

    I've done lots of brazing and welding using torches, so it's not new to me. Although the idea of practicing first is a great idea and I will do exactly that.
     
  8. Sep 11, 2010 #8

    oldman55

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    if you are going to do any brazing on refrigerant lines you need to run nitrogen through the lines to keep them from scaling. you also should either change or replace the filter drier. if you don't you stand a chance of moisture being in the system or scaling coming loose and causing a blockage.
     
  9. Sep 11, 2010 #9

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    Thanks, but I'm still trying to figure out how to do the soldering.
     
  10. Sep 13, 2010 #10

    oldman55

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    if you want to solder the hole shut you will need some silver solder, your friend should be able to get it where he works. If he can't get any I have also seen it at Tractor supply. as for the torch, if you can find one the pro's use the turbo torch is good up to about 5/8 line any bigger you can't get the pipe hot enough. you said you had some torches, honestly that is probably you best bet. just remember that you are brazing so no flux,that is why you put nitrogen though the lines is to assure a good clean bond.
     
  11. Sep 13, 2010 #11

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    Ok, that's what I was after. No flux. Do you sand it clean like you would copper for soldering?

    I have brazed lots of things with fluxed bronze rods. I've repaired frozen and broken water pumps this way. Just never messed with refrigeration lines. And never used silver solder. I have a tube of it that may be very old, but it's still silver solder so it should work.

    Anything else I need to know before plugging the hole?
     
  12. Sep 14, 2010 #12

    oldman55

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    you only need to clean the pipe if it's really oxidized or if there is some tape residue. if you aren't sure you can use some sand screen on it. I looked at our local tractor supply store and the have some 1\8" brazing rod called weld-it, made by Hobart so if you can find a Hobart dealer you should be able to get it. this stuff is in a flat rod and not in a roll because the silver content makes it to rigid to roll up. If you have something that rolls up you might want to check the silver content. the stuff you get in the flat rod has a high silver content. if you use the rod and get a good weld the copper pipe will give out before the weld.
     
  13. Sep 14, 2010 #13

    Speedbump

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    Thanks,

    I think I have enough ammo to give it a try. First on another piece of copper to get used to the heat needed etc. Then I think I can get the job done.

    We are probably going to have to change out the reversing valve, but I think I'll let him handle that one.
     

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