Flow Meter Water Usage Way Off!

I’m hoping someone can point me in the right direction here. I’m trying to calibrate my zones with my Toro TFS-100 flow meter. If I run a calibration test on zone 1 for 1 minute, it comes back and says the baseline flow is 8.2 gpm. Watching my irrigation meter while that 1 min run is happening only used 3 gallons. Is there something wrong with the way the flow meter is connected to the controller, or is the rachio still calculating things based on sq ft, nozzle in/hr, etc? I have the red wire of the flow meter connected to the S1 terminal and the black wire connected to the VAC - terminal. Thanks!

Anyone run into this type of issue?

Yes, in my case, a Toro TFS-075 that reports usage by about 5 times actual usage. @MeterManSays has been encountering similar issues as well. We are in correspondence with Rachio now. Stay tuned.

Believe identified an issue with kfactor/offset, hope to have corrected today.



Red wire should be CONNECTED to “s1”:and black to “sc” unless you have a Rachio 3 than it would be vac-24. The way you have it connected will cause it to misread flow exponentially if your box is a gen 2 controller.

@ox1574 @dgb This issue should be fixed. One of the mobile clients was sending incorrect kfactor/offset (reversed).


I checked my meter last night before my flex schedule ran this morning, then compared the app usage # vs actual on my meter. It’s now much closer than before, but now the app is reporting 18% lower than actual usage. Reminder that I’m using a TFS-100. I used ~260 gallons shown on meter and app says 213. Thanks

I am just curious. What model of a TFS-100 do you have with a display? I can’t seem to find that model.

I’m not sure I understand your question. The TFS-100 is my Toro (Badger) flow sensor, and the meter I’m referring to is my separate irrigation meter.

OK. When you said “shown on meter”, I thought you meant TFS-100.

I meant to do this last week to help out people who noticed a change after the coefficients were corrected last week. Here is my experiment:

I injected a known 20.0Hz signal (verified by oscilloscope) into a GEN 2 unit after Franz fixed the coefficients last week. Using the published K and offsets which use the equation GPM = (freq + Offset)*K, I filled out the table for every meter in the app to verify that it converts correctly.

It would appear that they all work correctly now. For your situation specifically, 18% under counting on a paddle meter is not that atypical…particularly if it is older.

Hopefully this helps.


Thanks. The system is only a few weeks old and the flow sensor was brand new, but not sure on actual manufacture date. I will keep my eye on it and see if it’s consistently off by ~18%.