Flexible Daily Schedule: Run Times & Water Use


#1

Ok. I installed my 8 zone unit and input my square footage per zone. After that, I looked at the expected run time for my first run of the system. It is saying that the Rachio will run my sprinklers for a WHOPPING 8 Hours and 36 MINUTES. This seems like an insanely large amount of water. Can this be right? As such, I changed one zone which has some trees (not trying to water them) to just cool season grass and that got it down to 6hours and 16 minutes. But again, that too seems far to much water/cost. My very first run using my Rachio will be on Sunday. I figured I should not start it for the first time until the weather reports are not showing rain.

Inputs are as follows:

Flexible Daily Schedule
Square footage: Z1-1080, Z2-1080, Z3-500, Z4-500, Z5-1750, Z6-1750, Z7-683, Z8-683
Vegetation Type type: Cool Season Grass Z1-Z2, Z4-8; (w/partial) shrubs in Z3
Soil Type: Clay Loam
Exposure: Lots of sun Z1, Z2, Z3; Some Shade Z4,Z8; Lots of shade Z5,Z7; Mostly shade Z6
Nozzles: Rotor Head Z1-2,Z4-8; Fixed head Z3
Slope: Flat surface Z1-Z5,Z7-Z8; Slight Z6
Root Depth: Z1-2, Z4-Z8=6; Z3=15
Watering Schedule: Flexible Daily; Currently shows watering to be done on April 22(6hr,16min), 28(6hr,16min), 29(6hr,16min) & May 1st(6hr,16 min).

I’m using Rainbird 5000 nozzles (90+% of the lawn) with specs of:

Precipitation rate: 0.20 to 1.01 inches per hour (5 to 26 mm/h)
Radius: 25 to 50 feet (7,6 to 15,2 m)
Radius may be reduced up to 25% with radius reduction screw
Pressure: 25-65 psi (1,7 to 4,5 bar)
Flow Rate: 0.73 to 9.63 gpm (4,2 to 36,6 l/m)

On the high side, 6 hours(360min) x 9.63gpm = 3,466.8 gal/Run Cycle. Now not sure if I am to multiply that number by the total number of sprinkler heads I have installed(???) but are the run times normal? Should I go back to the default 500sqft?

The Grass Seed supplier indicates that for the tall fescue type that I have I should only be watering 1" per week. They say that this will cause the grass roots to grow longer (max of 4 ft over time) and become more drought tolerant. So, considering this schedule and the seed type this is going to be an interesting summer…


#2

@garyjnj1, welcome to the Rachio community! We hope you’re enjoying your controller and learning more about your lawn.

Square footage does not affect the zone durations; it’s only used to calculate estimated water usage.

Are you using the default precipitation rates or did you create a custom nozzle? The values provided indicate you’ve done your research and understand there’s a wide range in water output per zone. If a zone’s precip rate is 0.20, it will need to run 5x longer than the same zone with a precip rate of 1.0.

I’d recommend you perform a catch cup test to calculate the exact precip rate and efficiency (DU) for each zone.

I hope this helps. Let us know if you have any other questions.


#3

Hi Emil, the precipitation rates are the default values. I have not created a custom nozzle.In order to zero in on this value I would need to know the pressure on the line on any given day (assuming it may fluctuate- not sure if the Rainbird system came with a pressure regulator installed by default).

Any word on what the number of sprinkler heads indicates? Would it be the number of heads x the 9.63 gpm value(@ precipitation rate of 1) to better determine gallons used? Any word on if the total watering time is acceptable and normally should be encountered? Also, any word on what the Grass seed company is saying the need is vs what the Rachio watering times indicate?


#4

Also, in the estimated water usage formula(( (SF x PR) / 96.25 )) what does the 96.25 constant represent?
I presume you are using the SF instead of number of nozzles due to variations in placement, coverage and nozzle types.


#5

Hey @garyjnj1-

Flex can be a bit of a shock for people because it is a change in the way you water. Flex waters deeply, and much less often. This is actually a healthier way to water for your plants, but isn’t typically what people have done in the past. I would assume this is what is causing the discrepancy between the grass seed company and our recommended durations- however if you have a precipitation rate of 1 in/hr and you are putting down an inch a week, this would be an hour long watering a week, I wouldn’t think flex would be too far off from that?

A couple notes I have based on your settings. The first thing I would check is the actual run time of each zone, which can be found if you go to the editing screen for your schedules, and select “Durations”. Are these as long as the schedule run time? The reason I ask is Smart cycle breaks your schedule up, and can be deceiving when looking at the overall run time of a schedule. Clay loam is a relatively fine soil, so it requires longer soaking periods. If you want to post a screenshot of your durations and/or zone settings, that could be helpful!

You are spot on with your assumption of why we use sq ft/precip rate for usage. It would actually require more inputs to determine our schedule durations if we used gpm over in/hr. The 96.25 constant is just a unit converter to go from in^3/hr to gal/sec. We then multiply that gal/sec number by your duration in seconds to determine usage.

McKynzee :rachio:


#6

Hi Mckynzee, below is the zone time breakdown. Zone 8 got cutoff due to my screen size but it is 43min.
In terms of the calculation for water usage, is it possible in the next version to add a test similar to what Rachio does now where it asks us if our heads are running? Only this time, include a location to enter the starting meter reading. Have the sprinklers run for 1 minute, allow the user to then input the resulting meter reading. Essentially, you are using the water meter as a flow meter. Once you have these values it can then be used to extrapolate gpm over all schedules. Finally, allow us to put in our cost per gallon so we can see on a daily basis how much we are spending and what to expect on our quarterly bill. This method, I feel, would be better then a cup test since you get the actual reading which indigenously, compensates for the pipe diameter and pressure. You can still leave the easy option for those that dont care. From what I can tell, the cup test seems best applied to determine the relative effectiveness of spray heads in in watered zone area. If the spray heads are not each calibrated, results will be variable. In short, the test probably works best in ensuring that a zone is getting enough water, as opposed to determining the total volume of water expended by the entire system per run. Nevertheless, I love the extrapolation method that is in use. It is very creative. I just want to zero in on that “Real” number so I can budget water usage/expenses properly. Its why I switched from Rainbird to Rachio.