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3/4" from meter to house

Discussion in 'Irrigation' started by zliminator, Oct 16, 2006.

  1. zliminator

    zliminator LawnSite Member
    Posts: 82

    If I tap off from just after the meter with 1", can I increase the expected GPM from 11 to 18?

  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,686

    What size meter? How close to the curb? What's the static water pressure?
  3. MarcSmith

    MarcSmith LawnSite Fanatic
    Posts: 7,157

    I always thought that if you increase the pipe size that you will not get any difference in flow or pressure as your limiting factor is still the 3/4" pipe. In that the water cannot flow any faster through the 1" pipe than it can in the 3/4" pipe that is feeding it...
  4. jerryrwm

    jerryrwm LawnSite Bronze Member
    Posts: 1,274

    You can push water through a pipe at velocities that exceed the recommended 5 fps. for plastic pipe, 10 fps for metal pipe. The pressure loss is greater at higher velocities which makes it impractacle. You can get 20 gpm through a 3/4" line and 40 gpm through a 1" line, but the pressure loss is going to be astronomical and the potential damage due to water hammer in exponentially increased at higher velocities.

    For example it is not unusual to have sprinkler zones of 15-18 gpm through a 3/4' meter with a short 3/4" copper supply.
  5. zliminator

    zliminator LawnSite Member
    Posts: 82

    The meter is 3/4", its about 10' from the curb and the static pressure is around 62psi. I hooked up a test manifold coming right off the shutoff valve with (6) 3/4 rotor sprays rated at 2.5 gpm each and the pressure went down to 35psi. It that helps.

  6. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,686

    Heck, with a curbside meter, you could just look at the meter for a flow rate, and forget the 'test manifold' - anyway, it doesn't look like any (at a useful pressure) 18 gpm is in your future here.

    PROFESSORRAIN LawnSite Member
    Posts: 246

    Make Things Easy Put A Gauge On The Front Faucet Of Your House Turn On Water To Gauge.go To Back Of House Turn On Faucet.this Is What You Call (static Pressure & Residule Pressure) Static Is When The Front Is On.residule Is What The Pressure Is When The Water Is On In The Back Flowing.

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