Quote:
Originally Posted by AC_Hacker
This may be all well & good, but if you start hacking your system, changing refrigerant, changing compressors, changing HXs, even changing appreciably the length or diameter of your lines that run from your compressor to the HXs, then the specified weight of the charge is no longer relevant.
At that point, going by pressure that applies to the refrigerant in question as I have done, or testing for performance as randen has done, or testing for super-heat and sub-cool as Vlad and GregC have done, can lead you out of the woods.
I hope that Vlad and GregC are reading this post and can weigh in on this matter, as it is important and they have a respectable amount of expertise on this very issue.
Best,
-AC_Hacker
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I was responding about an inquiry mini-splits, I assumed they means inverter mini-split. Not sure how well that would work changing refrigerants in those which would then require that you do a bunch of a guess and check and hope efficiency is similar to what you had before and that you won't freeze up a coil or slug the compressor. Changing an inverter compressor might be a little tough but the charge would still be a similar weighed in amount. If changing the HX you could adjust the weighed in charge by the change in tubing volume, if changing the length or diameter of the lines you can adjust the weight based on the manufacturers numbers on how to adjust charge as those numbers would be relevant in that case and I'm not sure of any manufacturers that don't provide the adjustment for changing the refrigerant line length, diameter adjustment could be calculated based on numbers from other manufacturers for diameter adjustment for the same refrigerant. So you can still weigh in the charge in almost all cases with a mini-split. Granted you aren't required to weight it in and can't if changing refrigerants but if you can weigh it in, you'll likely be better off, especially with an inverter unit.