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passandscore



Brazing on an Operating System

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It goes without saying that brazing on an operating system is not recommended. Actually,it's highly discouraged!

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Unfortunately there are those moments when desperate times call for desperate measures. I was on call and had to travel two hours out of town hoping I had what I needed. I arrived to find a copper liquid line that had been worn through by the clamp that was meant to support it. I began my system pump-down procedures when I discovered that the king valve passes refrigerant even when supposedly fully closed (pic 2).A technician had flagged the deficiency but never rectified the problem so here I stand in the middle of nowhere with a system I need to keep running and no practical way to do it. After exhausting my options I realized that I really only have two:
1) Drive back to the city and try to acquire the gear and components. Need I remind you that it is after hours and I am two hours out of town.
2) Have the operator run the system in a partial vacuum while I heat the pipe and attempt to braze.

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Opting for the latter, I gave it a go! It is certainly a touch-and-go procedure. Too much of a vacuum and the brazing material will be drawn into the pipe, while too much pressure (3psi)causes the material to spit out and form pin holes. I was able to braze over the hole with what can only be described as a bird crap of a finish(pic 3). Certainly not the cleanest but unquestionably effective. The next day all proper modifications and repairs were completed.
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Working in Refrigeration , Working Blogs


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