1/4" Water Flow Sensor Food-Grade Switch Hall Effect Flowmeter Fluid Meter Counter Connect Hosepipe 0.3-6L/min

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 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.

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.

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.

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.

It arrived very promptly but after doing some testing it turns out that I didn’t need the switch. A small amount of debris was plugging the circulation tubes on my Laser Cutter so I ran water backwards through the system flushed it out and now everything works as it should.

That 3/8 " is the od of the tubing used not the ID