RE: Ductless Mini-Split air flow verification testing, how to do it?

I have been watching videos about air flow and how to calculate air flow with the hotwire anemometer and the vane anemometer.  What I have not been able to find is how to use one of these tools to check/confirm air flow through a ductless mini-split unit.  Has anyone ever performed this test or seen any guides published from leaders in the industry like Bryan?

Wvanderslice Rookie Asked on December 21, 2018 in Residential HVAC.
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This answer might not be the best, and, I would love to be educated otherwise, but, here’s what I do:

Since mini-split blowers use a speed sensor fed back to its control board, the rpm of the motor should be consistent, if not, the motor is bad (right?). When I’m checking mini-splits I run all units in high speed. I use the manufacturers submittal data to determine the CFM and plot that into the Testo smart probes app and use 2x 605i thermo-hygrometers with that cfm. With that I am able to check the whole systems performance based on the BTU output. So far it has worked VERY well for me as I have been able to find leaking/improperly installed systems that would have otherwise gone unnoticed.

Testo’s anemometer does have a cfm measurement for “outlet” measurements vice just ducts, I however question this measurements validity since I can’t accurately measure the usable outlet size to even calculate the CFM properly. Hence why I use submittals.

Hope this helps!

Rookie Answered on January 11, 2019.
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