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Flow sensors review

Review includes three most widely used models of flow meters — Koolance INS-FM17, Flow meter GMR Brass G1/2, Aqua Computer Flow sensor high flow G1/4

Testing configuration and results

  • Pump: Aquastream XT ULTRA
  • Tubing: Tygon 3603 ID1/2″ OD3/4″
  • Data acquisition devices: Aquaero USB 4.0, T-Balancer bigNG, Koolance INS-FM17 readings were monitored by EVEREST v5.30
  • Two 10 litre canisters

Testing methodology:
Flow sensors were installed in the loop in series in a horizontal position. Data was collected twice — in the beginning and in the end of test. Then calculated average value was compared to the reference value.
Three most common values were selected. Tests were repeated three times for each measurement point. Testing results:

Flow meter testing results

Koolance INS-FM17 slightly overrated data compared to reference flow meter rate. On the other hand GMR Brass G1/2 flow meter — significantly underrated flow meter rate. However, data provided by Aquacomputer Flow sensor high flow G1/4 nearly coincides with reference flow rate values. Reading tolerance of flow meters:

Tolerance, %
Measurement pointKoolance INS-FM17GMR AFS1-B MessingAC Flow sensor high flow
2.5 l/min9.37-8.343.32
3.33 l/min6.20-7.64-1.05
4.17 l/min3.96-5.29-0.38

For flow rate accuracy Aqua Computer Flow sensor high flow G1/4 receives “HW-lab Editor’s choice” award:

HW-lab Editor’s Choice

Koolance INS-FM17 flow meter that don’t need any data acquisition device receives “HW-lab Recommended” award:

HW-lab recommended


# Avatar James,

My Koolance flow meter melted placed at the end of the loop after my 2 ATI 4870×2. It can’t handle heat!!

# Avatar

What exactly do you mean by saying that your flow meter “melted”?
Can you describe it in details?

# Avatar JN,

any Koolance product that has acrylic in it is JUNK; too thin, poor quality.

# Avatar Voiager,

I own a computer Water Flow sensor “High Flow G1 / 4, which I connected on a 5 Aquaero XT, but I see no value. I checked the contacts but it is entirely correct. Can you help?


# Avatar

Sorry, but we don’t have an Aquaero 5 at our lab yet.

# Avatar Sprucemoose,


I just bought one of the Aquacomputer High Flow sensors, however there is a distinct clicking noise coming from the device, it’s almost completely silent when running at 1,8L/Min (30%PWM), the clicking starts being audible at around 2,4L/min and increases drastically with flows above this. Max flow I get while using my MCP35x pump i 6,7L/min.

It is even so that the vibration traveling through the tubing to the radiators making a resonating humming sound when the radiator is installed in the case.

I have bled the whole system properly, so I don’t think that air is the problem. I’m wondering if you had any problems with your test-sensor?

# Avatar Jan,

I have the Aqua Computer Flow sensor “high flow” G1/4 for aquaero ( in my computer watercooling system. For connection I use this ( cable.
My pumpe is aquastream XT USB 12V Pumpe – Ultra Version. (
My problem is that I don’t get any rpm signal when I connect the flow sensor to the aquabus/flow connection on the aquasteam. Tried to chance the impulse and the aquabus/flow settings in the software but still nothing. Tried most settings I think :-p
If I connect the flow sensor to the main board I can read the rpm ie.speedfan.
Is there something wrong with my aquasteam?


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