Are the upper and lower parts of a two-pass U-tube symmetrical?
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Are the upper and lower parts of a two-pass U-tube symmetrical? Can leaks in heat exchangers be sealed symmetrically from top to bottom?
It should be based on leak testing; following blind rules without understanding the internal structure is not advisable, for reference only.
It is basically symmetrical, except that the middle row may also be tilted, but this is very rare.
It’s very simple: to block a certain tube, first supply compressed air to one end and see which end releases air; the two ends of these heat exchange tubes belong to the same heat exchange tube.
This post was last edited by wanlirn on 2022-7-29 at 15:32. You have to figure out which side is asymmetrical, which pipe is leaking and which one needs to be blocked; it’s impossible to get it fixed in one go – it may take repeated attempts. Once a pipe is blocked, even areas that weren’t leaking before might start to leak as well. It’s really frustrating. From my experience, heat exchangers are replaced when they start leaking after a few years of use
It is generally symmetrical; you can check the drawings for details