This was more to satisfy my own curiosity....but I wanted to quickly test the Koolance FM-17's accuracy against calibrated Dwyer flowmeters.

In use were Dwyer RMC-142 and -144 flowmeters (connected in series to essentially make a .2 to 7GPM flowmeter).

Flow is adjusted by varying pumping power (I have 4 pumps in this circuit, two of which are on variable controllers). The Dwyer data points are my best attempts at reading the readout and interpolating between the marks (when necessary). The Koolance FM17 data points are averages of 1 minute data logs (so really short considering a normal test for me is 75+ minutes). RPMs are logged with my CrystalFontz 633.

Here's the chart I made....



The two flowmeters basically read identically below 2GPM and above that only differ a little bit....the biggest flaw with the FM-17 is that above like 1.8GPM, it's little spinny-thing is spinning very fast and the granularity of readouts decreases. Maybe if it measured over a period of like 10 seconds rather than 1 second, or if the polling rate of the sensor were increased, it would increase accuracy at the high-end of the flowrate spectrum. Other than that, it's a pretty sweet $30 toy and surprisingly accurate (I really was shocked by it). It seems to be really low restriction as well, which is a plus.

Nevertheless, it's getting semi-retired and putting into duty as a passive measurement tool rather than something I use for data acquisition.