Vermont Flow Meter

Discussion in 'Maintenance and Troubleshooting' started by timothyf, Jan 19, 2016.

  1. timothyf

    timothyf New Member

    What is everyone's favorite in line water flow meter? The Omega FL-515 looks like it would work well, but seems pricy.
     
  2. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Not commonly used for residential systems. But you can look towards the pool guys for some that are somewhat affordable. I think I have a box of 6 still sitting around somewhere.
     
  3. Dan Dillner

    Dan Dillner Member

    I purchased a GPI (Great Plains Industry) GPI 01N31GM and it has worked well for me. The only draw back is I can't tie it into my computer.
     
  4. milkweed

    milkweed Member

    If I understand correctly the GPI 01N31GM might be a flow totalizer, not a flow meter, which is probably why it uses a turbine. I don't think that is a negative, just a distinction.

    The Omega website says "FL-505 thru FL-515: 50.8 (2") diameter", so does that mean the Omega FL-515 has 2" diameter connections?
    The Omega website also says "Pressure Drop: 4 psig Full Scale", I don't understand the difference between pressure and pressure drop, how would I account for the foot-head loss of an inline flow meter such as this?

    Most of the lower cost flow meters I have seen have stainless steel parts.
    Are there corrosion issues with water/ethanol or water/methanol solutions?
     
  5. Dan Dillner

    Dan Dillner Member

    "If I understand correctly the GPI 01N31GM might be a flow totalizer, not a flow meter, which is probably why it uses a turbine. I don't think that is a negative, just a distinction."

    You are correct in that this water meter does total. You reset it to zero and let it total for 1 minute to get GPM. If you need to have it calculated internally and displayed in GPM or LPM you need another water meter. For my set up purposes it works great.
     
  6. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    To measure pressure drop is probably more precise than a flow meter, and it does not introduce any flow resistance in the line.
     
  7. milkweed

    milkweed Member

    How do you do this?
    Would I install pressure gauge near the in and out lines of the heat pump?
     
  8. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    There is too much variance between the gauges. The best way in my experience is the same digital needle gauge inserted into the p/t ports
     
  9. milkweed

    milkweed Member

    So only use the P/T ports off of the intake and outtake of the heat pump?
    Is there any benefit to having P/T ports elsewhere in the loop? like just after the pump
     
  10. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Not really. The only item needing flow is the heatpump, and it is the only place which is calibrated to a have a certain flow at a certain pressure drop.
     
  11. weedy64

    weedy64 New Member

    An FL515 has 1" fnpt ports. At a flow rate of 15gpm through it you will get a pressure drop of 4psi across it. Can your system accommodate the measurment unit in place?

    As Doc said the tp points are calibrated by the manufacturer. The only value to an inline flowmeter would be on an open system where the HE gets fouled, you would see a drop in flow with a flowmeter. If im not mistaken the tp measurements would be in error and mask the problem.

    I found an industrial rotor type flowmeter with 1" copper lines I can insert inline to systems I want to troubleshoot.
     
    Last edited: Jan 17, 2017

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