3rd party flow meter - pulse requirements

post by Jack on Oct 1, 2024

I’d like to use a proper mag meter (that has a 10 year warranty) that gives a pulse output, but I’m having trouble determining what the Rachio will accept and I can’t find a real manual. So, my meter offers a pulse width which can be set within the range 0.3ms to 500ms in increments of 1ms. What will the Rachio 3 accept? I see reference to 24 VAC. I thought pulse systems were 24VDC? I guess I can buy one of the recommended meters otherwise. Rachio is in the mail, just trying to prep for install.

post by RPostWVU on Oct 4, 2024

There is more to meters than pulse width. There’s also K-factor, which is the number of pulses per gallon. Yes, the meters are 24VAC as the whole system is.

I was in a similar boat to you, but couldn’t find the answer, gave up and bought the one Everydrop. It has worked fine for 4 seasons, I take it out each winter. My one complaint is the meter loses its total usage number on power loss–so I put my system on UPS (it was available due to my fiber modem being nearby).

post by JBTexas on Oct 4, 2024

At this date, this is the list of supported flow meters in the Rachio app:

Some meters have variants/models that will behave like these. The manufacturers can usually tell you which those are.

post by eyal0 on Aug 31, 2025

Do you know what the signalling is on that meter? As far as I can tell, it’s a 2-wire signal where the flow meter is shorting the two wires at a frequency that is proportional to the flow rate. The proportion is the k-factor.

Do you know how long the pulses last?

post by Mikebp on Jun 2

Where can I find this list in the app? Looking to add a sensor to ensure nothing starts leaking when I’m out of town. Can you recommend the best value wired and wireless? I have one spare unused zone wire I could use, assuming it can share the ground/common for the solenoids.

Thanks!

post by JBTexas on Jun 2

Settings / Accessories, where you would setup (enable) the S1 and/or S2 terminals to use wired accessories. The same Accessories screen has an option to add a wireless flow meter. The list of supported sensors is where I constructed the list, which has probably changed.

post by Mikebp on Jun 2

Okay, found it, thanks man.

Any experiences you can share which I could leverage? I have the Rachio 3 controller and some iffy zone setup (2 zones connected to some of the same heads) on a 34yr old system - I’d like to ensure something doesn’t run on for 30-40hrs before I catch it - especially if we’re out of town.

I’m slowly getting it whipped into shape…but the forever water leak on a zone is creepy and $$$$.

Thanks for any anecdotes!

post by jadwin79 on Jun 5

Danger, Will Robinson! Don’t use unused zone valve wires. It often works, but you’re asking for electrical interference problems. And you can’t use the ground/common for the zone valves. The proper common for the flow sensor is the 24VAC - terminal. It won’t work with C.

One data point for people asking about pulse widths. The EveryDrop meters use a 1ms low-going pulse. The Rachio has no trouble decoding that. For those kind of meters frequency is proportional (plus a constant) to flow rate and is in the range of, let’s say, 2-100 Hz. Those outputs are pulse frequency outputs. The other kind, favored by Hunter, is "scaled pulse", where each pulse represents a certain number of gallons. Those don’t have K-factors or offsets, but just a gallons-per-pulse specification.

Finally, the S1/S2 terminals on the Rachio don’t provide 24VAC. It’s rectified 24VAC, which comes out to ~34VDC, but can be higher. There seems to be some variability in the components.

post by Mikebp on Jun 5

Excellent detail - much appreciated. Twisted pair okay or is shielded required?

Can one get away with repurposing an unused phone wire??? (At&T demarc is about 3’ from the sprinkler box).

Have a complex 80’ run…is the wireless sufficiently reliable or best just suck it up and endure the pain?

Finally any suitable in-house copper connected compatible solution that’s not huge $$$?

Thanks for sharing your experience!

post by jadwin79 on Jun 5

The official recommendation is shielded. That said, people use much worse wiring, including zone valve wires, all the time. If you have it lying around, try it, and upgrade if it doesn’t work. Twisted pair has real benefits for differential signals (which the flow meter output is definitely not), but it also has some lesser benefits for single-ended signals.

Whether wireless works depends on your definition of "complex". Obstructions like walls, and especially anything metal, will reduce or distort the signal. The WL-1200 goes through one external wall after at least 1/2 mile line of sight. It might be a bit better than the older WM-1000, but most importantly it doesn’t have the pairing requirement of that unit. You can buy a wireless meter and do a trial "range test" first to see if it works before doing the final install.