Installed my Rachio 6 or 7 years ago with 6 zones, all good.
One month ago I added Zone 7 after we took down a large tree in the front yard and now we just have grass.
This zone 7 is IDENTICAL to zone 6. 180 degrees rotor head with a throw of about 20’
Configured the same settings but when I check the schedule zone 6 shows 53 minutes while zone 7 shows1:35 and it’s repeating through the month.
What is the reason for these numbers to be so different? I also think 1:35 is way too much for that area. What should I do to fix this? It really looks like it’s bug in the software. I even disabled and re-enabled zone 7, reset advanced settings etc.
These are the settings:
cool season grass, rotor head, clay loam, some shade, slight slope
600 sq ft, 6" root,. 50% depletion, 0.46 in/hr nozzle
Flex day schedule, smart cycle, start at 1:30 am, allowed watering every day
I should also add that when I tried to figure out what was going on, the only variable that would have an impact on the irrigation time is the nozzle inch per hour. So if I double the nozzle in/hr to 0.92 then the time will half and make zone 7 and 6 have the same irrigation time but now the nozzle number is wrong!
I assume you are using Flex Daily schedule? I’m most familiar with that, as it’s all I use.
Anyhow, the things that determine how long Rachio waters each time is the Available Water (set by the soil type), the Root Depth (set by the grass type), the Allowed Depletion, the Efficiency and the Nozzle Inches per Hour (both set by the Spray Head Type, or manually if known). I don’t know what you mean by the “nozzle number” in “now the nozzle number is wrong!”
Anyhow, for Clay Loam soil, the Available Water is 0.2 in/in. For Cool Season Grass the Root Depth is 6", for Rotor Head the Nozzle Inches per Hour is 1", but you have apparently set it for 0.46"/hr(?). The default efficiency for a Rotor Head is 70% (you may have set it differently).
Time of run is calculated as:
Time(hr) = Available Water x Root Depth x Allowed Depletion / Nozzle Inches per Hour / Efficiency
in this case:
Time(hr) = 0.20 x 6 x 0.5 / 0.46 / 0.70 = 1.76 hours or 1:52. If the efficiency were 82% it would come out to 1:35 in your case. So, it seems to me that the Rachio calculated time is correct.
Why is it different? I’m guessing that sometime during the 6-7 years you’ve been using Rachio, you manually set the time in zone 6. Once a time has been set manually, in my experience, it doesn’t want to go back and calculate correctly, requiring deletion of the zone and starting over. We ALL think Rachio waters too much when we start out. But after learning, or measuring, the proper settings (Nozzle Inches per Hour should ALWAYS be measured IMHO), it usually comes out right.
Oh, IMHO Rachio uses too low an efficiency when setting up zones. If you actually measure water usage (water meter usage over time), that is the actual water provided. Efficiency only comes in when one area receives too much water, another area too little, and Rachio tries to apply more water to the areas needing it. I personally think that’s a bit of hooey, as I cannot visually see a difference in areas of my yard that get too little or too much water; they tend to equalize one another. Note: this is just my 2 cents, not a generally held belief.
Thank you rraisley for your detailed answer! First, let me answer your questions and make some clarifications.
With “nozzle number” I meant “Nozzle Inches per Hour”
I am not a sprinkler system engineer but to me “Nozzle Inches per Hour” is a very confusing definition. What if I have multiple sprinklers covering a certain area? Do I add each unit in/hr numbers? What if the surface is much bigger? or smaller? Anyway, I believe what Rachio means for this field is the “precipitation rate” which should be calculated by using catch cups placed in the zone. I haven’t done this yet but I will soon.
For now I came up with a Precipitation Rate (in/hr) of 0.46 by entering my rotor head manufactured provided 3 GPM and the irrigated area of 630 ft^2
Why would a rotor head be 1" per hour? wouldn’t this number change dramatically based on the set throw and the angle covered?
As you can see I am very confused about all these numbers and to me they make no sense because some should be absolute number, like in a fixed nozzle head and some other relative numbers like in a rotor head. I think the Rachio App should only be asking one information which is how much water is deposited on the lawn in a certain amount of time, that’s it, no area, no sprinkler type, no number of heads.
Anyhow, thank you for providing the calculation. That makes things so much clearer! As you guessed zone 6 and 7 are identical and all the numbers you used in the formula are exactly the same for both however zone 6 gets half the time of zone 7
Probably you are right that there might be a bug or there is a manual time setup somewhere, can you help me find the manual time setting? I looked everywhere in the App but I can’t seems to find it.
I’ve used catch cups. They’re a pain in the butt. In fact I’ll send the ones I have to anyone that want’s them if they pay postage. The reason I don’t like them is the results vary SO VERY MUCH depending on the location of them. Move them a couple feet one way or the other, and get a completely different result. Yes, my sprinkler flow isn’t even, and these tells you that, but it can be so very different. I prefer to simply (for me, at least) measure the total water flow to a zone for a given time (using the water meter), to calculate total GPH to the zone, and measure the area of the zone being watered, and calculate that to a final Nozzle Inches per Hours, as you have correctly done.
“Precipitation Rate” may be more understandable, but this isn’t really precipitation, it’s irrigation. Maybe Irrigation Rate?
Well done on the calculation! Seriously, most people have no idea how to do this! But do you have only a single 3GPM rotor head that irrigates that entire 630 ft^2? You are absolutely correct that if that 630 sqft zone has a total flow of 3GPM to any and all rotor heads, then the Precipitation Rate would be 0.46 "/hr.
I think they have used standard tables of manufacturer’s sprinkler head types, which usually have spacings and such and total "/h rate based on that. My experience is that most installations are not done to the book, and usually provide less water than the manufacturer (and Rachio) intended.
They kind of are asking that, in the Advanced settings, with the Nozzle Inches per Hour, but I agree that the terminology isn’t great.
It’s not very intuitive. You enter all this fancy information for Rachio to calculate times with, and it tells you the times, but then you can go to the Schedule and change all the times manually. Once that’s done, IMHO, no zone changes will change the time. The schedule uses the calculated time, unless you change it, then it always uses the time you entered, but doesn’t warn you about it. I would create a new Schedule with the zones that you want. I think you will find similar zones to have similar times that way.
Now I feel I am getting somewhere! Thank you for confirming my precipitation rate calculations and yes, I do have single rotor head for each zone. I know, that’s probably not ideal but it was done to simplify things and reduce cost. I also live in south-east PA where we get regular rain in the summer and the whole idea of having an automatic irrigation system was to just help out in case of unusual 1-2 weeks of drought. No one around here has a sprinkler system in their yard.
I finally found the section in the app where you can change the times, totally unintuitive! Now I seem to remember changing these numbers here when trying to correct the watering times because they were way excessive. You are right, apparently there is no place to reset to automatic mode except for removing a zone and adding it again.
This conversation just confirms my intuition that Rachio had a good idea with this product but unfortunately the software implementation it’s very poor. Looks like they tried to please people that know nothing about irrigation and professionals as well but the result is a Frankenstein of a system.
I think they should make you chose between two modes, a default easy setup or an advanced setup. The easy mode you just answer a few basic questions and after a week or two the App asks you to take a walk in the yard and tell it if it looks too wet or too dry, similar to the way a Nest learning thermostat works. The advanced mode should be available to professionals where you can enter all the details about your setup.
I think I’ll take the simple path to my over irrigation problem and manually set the irrigation time for Zone 7 as I did for all the other zones. After all it worked pretty well with manual times all these years, what do you think? My other option is to go the automatic way but provide a fake precipitation rate to make the irrigation time what I want it to be. What would you do?
Since your irrigation requirements are limited to only occasional use, due to normally having enough rain, your simple method should be fine. It’s worked for you for many years, so it shouldn’t be a problem going forward.
For those of us in the South (Carolina), we need to dial in our settings pretty well to keep the grass green without excessive water usage. Rachio’s Flex Daily does that for me.
And I partly agree with your assessment of Rachio’s program. They have a great thing going, with some flaws. And they don’t seem to be eliminating those flaws. I’m a programmer myself, and have always listened to my customers, making easier and better ways for them to accomplish what they want to. We could use more of that.
I know I’m late to the party here, but honestly, with a PR of .46", the time actually sounds about right. My Hunter MP Rotators have a measured .58-.65" depending on zone, and my zone run for 1h10m each on average. For the zone that you say is identical, did you manually adjust the run time down at some point?
You have to think, you have a single rotor that is making a full 360 sweep, and covering a sizable area. It is going to take a while to put down a measurable amount of water.
