Flow Estimates Way Off


#1

I installed my flow meter yesterday and the app switched from minutes of watering to gallons. I liked that idea, what I didn’t like was when it converted minutes to gallons, the estimated gallons used was four times greater than the actual. For example, zone 6 measured 463 gallons used this morning, but the estimated gallons for the same zone the day before was 1,810. Since it measured the flow rate at 10.3 GPM and ran for 45 minutes, why would the estimate be so high?


#2

I would think this flow meter would measure actual flow. Another thread that creates doubt on whether I need a flow sensor.


#3

I think the flow meter is accurate. During the calibration phase I went to the basement and recorded the values on the water meter after each zone ran. I had to convert from cubic feet of water to gallons per minute, but the numbers were close enough to give the new gadget a thumbs up.

At first I was disappointed because the values were twice what they should have been. I realized the calibration ran for 2 minutes per zone, the first minute to pressurize the line, and the second minute to take a measurement of the flow.

The problem is in the app, when it converts the estimated water usage before the flow meter was installed from minutes to gallons. The gallons measured this morning were what I expect given the flow rate and watering duration.


#4

I’m guessing that the old method of estimating gallons is used for watering prior to meter installation. Probably does not use the calibrated flow rate to recalculate past gallons? The without a flow meter method assumes perfect precipitation rate across an entire area — my guess is estimates would generally be high.


#5

Estimate is generous, I would label it somewhere between guess and wildass guess. If I was writing the app, I would code it such that every time the calibration was run, I would replace the guess with duration X flow rate.


#6

@SwordOfTheSpirit, sounds like you’d like to see the historical estimated usage reconciled with the new actual usage?

@robertokc, the Wireless Flow Meter will report actual usage as long as it’s online. If it goes offline, we’ll report estimated usage (notice the blue and gray color key).


#7

Yes, instead of using a wild-ass-guess, why not fill in the estimate using actual data from the flow meter (calculated rate in GPM after the calibration) times the zone run time saved by the Rachio.

If I had this number, I might be able to take the numbers to my municipal water & sewer department and argue that they are over-billing me for sewer because I use water for lawn irrigation.

I can’t possibly take a set of wild-ass-guess numbers which exceed my total water usage as evidence.