Water flow sensor calibration


I replaced the tee (not cheap) and made sure there is at least 7 inches down stream and QWERTY inches up stream. That made the difference. I hooked up a hose with a shut off valve to a dead grass circuit and filled a bucket multiple times representing 12 gallons. The app showed 14 gallons different before and after as compare to 33 gallons with bad setup before.

Now to see what the numbers are in the real world.

Sure can’t wait for the day when you have per zone totals and better yet a second total with per zone for the last run.


Hi again. After my water flow sensor worked perfectly for about a year and measured consumption very accurately version 3.0 of the rachio app came along and messed it up again.

Initially, after the update, my controller was reporting some ridiculously high consumption numbers (over 100,000 gallons per month, when the city meter reported about 6,000, as usual). I thought that was some kind of a temporary bug, and waited patiently hoping it would be fixed in the next minor update. And it did. My consumption numbers this past month have been much more reasonable, but not very accurate.

These are my last two measurements:
Measurement 1: City meter: 323 gal, Rachio: 273 gal
Measurement 2: City meter: 135 gal, Rachio: 86 gal

My question is, did the latest update and the introduction of the new flow sensor from rachio somehow change how the controller interprets the signal that comes from older sensors, and in what way?

As I had mentioned earlier, my sensor is CST FSI-T10-001.


There was an issue with the firmware that is since corrected.

This should be working similar as it was before. I will have the team do some calculations on your account and verify the accuracy. Thanks for reporting these discrepancies.


@franz thanks for the quick reply. The values of K and Offset that worked well for me before were

K=0.2859 and Offset = 0.20

I am not sure if those got reset somehow after the latest update, but please ask the team to set those values again for me and let me know so I can do another measurement. Thanks!


@vmetsis kvalue and offset are correct in the system. I am going to DM you regarding further diagnostics.


I have a similar issue calibrating my flow sensor.

I have a Toro TFS-100 Flow Sensor and a Rachio Gen 3.

I have a multimeter to test for Hz down to .01Hz so I can get an accurate measurement on the frequency for the equation:


The default Offset and K are as follows:

Offset: 1.2
K: 0.26112

I still need to get the frequency results for each zone which I will get later today.

If I get those results, as well as the estimated flow from the city meter, will someone be able to alter the K and offset values for my controller to get a more accurate reading?


John Duncombe

Trident Landscape Management