3/8" Quick Connect Water Flow Sensor Food-Grade Switch Hall Effect Flowmeter Fluid Meter Counter 0.3-10L/min

I made a project with a RPi5 to monitor my coolant for my laser cutter/etcher. I used this to make sure that I was getting flow from the coolant output of the laser to verify that there was no issues cooling the laser tube.I connect this sensor to a custom cable and 3D printed adapters for my coolant pipes. The system screen flawlessly tells me whether I have flow and how much!

I have tried these with my watercooling kit and they seem to play along just fine with the fittings. They seem compatible (after re-wiring the plug) with computer fans (electrically at least).Output (in Hz) appears to be "Liters/minute=Hz/200" (i.e. if you measure 1,4KHz it means that you have 7Lt/min flow) as measured with my oscilloscope and cheap flow meter.

I ordered this to test measuring low flows from chemical dosing pumps. The sensor must be an NPN (sinking) transistor, as it would only work when wired to a sourcing PLC input on my Micro 850 PLC.

As info, I ordered/received the 2pc Gredia GR-R401 G1/4 Hose Pipe flavor. I got 2 so I could disassemble one and have the other unfettered in case I destroyed the one I was frackin with. I am using this on a water cooled 3d printer hot end, to give Klipper programmatic flow indication. These are 3 full pulses per revolution (6 edges). As another user reviewed, there is a reduction of the ID on the inlet side of the flow meter. I presume this was so that there was a focus of pressure on the rotor blades. It is 1.5mm in diameter (checked with a 1.5mm shaft). At ~35 deg C coolant temp, I am getting ~900-1000 PPM (~333 rpm @ 3 PPR). As the fluid warms, it becomes more viscous and flow increases. I am happy with the product. I opened the orifice on the 2nd unit to 2mm and will test to see if I get comparable usability with the larger orifice, and see if I get overall better flow/performance from the cooling system.

I use it to sense the water flow of my RO system and trigger the UV light to sanitize the water. It worked as expected no complains.

I would not use this for anything where you need a reliable measurement. Initially worked great (with filtered water) but within 2 months it measured much lower flow rate than the actual flow. Seems the turbine doesn't always spin fast enough, allowing water to pass over it without being counted.

I received the 3/8" pipe threaded connector model, installed it, turned on the water, and watched water seep out through the threads. I used teflon tape, the female threads are in new, brass fittings (no wear). I am returning these.That said, I also ordered, received, and installed a similar meter that uses 1/4" shark bite connectors and that one does not leak at all, so I will be replacing the threaded model with a shark bite model.UPDATEI have three of these installed in my device, all different models. I found the threads on the threaded models to be "European" v. "American" and so not useful for me - the threads leak and the suggested solution is to load up on thread seal, which is not acceptable. That said, I do have a 201 and its threads seem to work well with my "American" threads. The shark bite models have never leaked and are very easy to install, especially with poly tubing. One of those, a 301, runs continuously for 10-14 hours, most of the time "dry", driven by a vacuum pump, and can get very noisy.

Replaced the connecter with a 3-pin 12V RPM PC connector. Setup a small external loop for testing. Flow should roughly be 25% - 30% of RPM value.This is based on the Alphacool DC LT 2600 that is being used has a max flow of 100 LPH.