Flow sensor on unions

Discussion in 'Irrigation' started by cjohn2000, Jul 12, 2013.

  1. cjohn2000

    cjohn2000 LawnSite Senior Member
    Messages: 570

    I have a fun resi install 120 psi static, 30 gpm at 60psi dynamic. My question is how do you install your flow sensors. I would like to install this next one on unions. Hunter reps have told me this is a bad idea. I can't see any issues with this as the union is full port straight through and a bad glue joint would cause more turbulance. I searched and saw a sensor for calsense on brass unions on a old thread. I will try and post pics next week. :waving:
  2. Mike Leary

    Mike Leary LawnSite Fanatic
    Messages: 23,171

    Research your question a little more. Rain Master & Data Industrial specs call for "un-obstructed flow" on both ends. Why put unions in anyway? Everything can be serviced from the top.
  3. SoCalLandscapeMgmt

    SoCalLandscapeMgmt LawnSite Silver Member
    Messages: 2,155

    We did a 2" Data Industrial PVC flow sensor with a couple of unions. We put about 24" of SCH 80 PVC on either side of the sensor between the sensor and the union. Didn't seem to have any issues with it. Data Industrial calls for a minimum of 10 times the pipe diameter in length on the downstream side of the sensor and 5 times the pipe diameter in length on the up stream side of the sensor.
  4. Irrigation Contractor

    Irrigation Contractor LawnSite Senior Member
    Messages: 423

    Like Mike mentioned, be sure to follow the manufactures instructions. Each are different, but the reason a specific amount of straight pipe is required before an after the sensor is to avoid flow deviations that effect the sensor readings.

    We have installed close to 100 flow sensors and they are extremely accurate, very helpful and we wish we could have them on all of our jobs.

    Once you use them especially with a central the amount of data retrieved is amazing and I cannot tell you how many times we use the flow sensor to test for various concerns from the office without having to go to the site. I am not saying regularly schedule service is not needed, it is just something you will learn using the flow sensors over time.

    I do the like the new Baseline Flow Sensor, Master Valve and Decoder all in one units. (Hydrometer)
  5. cjohn2000

    cjohn2000 LawnSite Senior Member
    Messages: 570

    I know Hunter's is 10 times the dia. of the pipe. As to why put it on unions it is more of a addon for later, insert a blank piece of pipe between unions. Those baseline hydrometers look pretty complex.

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