Rachio Schedule vs. Well Pump (with data!)

Sharing some observations…

Our irrigation system was turned on yesterday now that winter is (hopefully) gone for good. This morning was the first Flex Daily watering since V3 arrived. I edited our Flex Daily schedule to put a 5 minute delay between zones to give our well pump a chance to recover as our Hunter Pro-C had a 6 minute delay configured between zones.

Another change since we closed up the irrigation system last fall was the installation of a Sense home energy monitor in late March. Sense was able to identify our well pump motor and I now have access to when the pump is running. The pump itself is set to turn on when the water pressure wank reaches 35psi and turn off when the tank is recharged to 50psi.

This morning I spent a little time making a chart of when Rachio had a zone active, when the zone delay was active, and when our well pump was running. The results are… confusing me a bit.

How to read this chart. Anywhere a colored line is on an integer it represents the zone active. The blue line just below the integer line represents the well pump being active. The orange line just above an integer line represents the 5 minute zone delay.

Here’s what I observe.

  1. The well pump always turns on 1 minute after Rachio starts a zone. Theoretically this means the pressure has dropped <35psi in a single minute of run-time.

  2. Each zone runs 26-27 minutes.

  3. The well pump only runs for 18 minutes each time leaving Rachio running for ~8-9 more minutes on its own per zone without the well pump running.

  4. The behavior repeats perfectly for all 7 zones.

I have a theory I wanted to run by the community.

I don’t know the actual starting PSI of the water pressure tank when zone 1 starts. It could be 36psi just on the edge of the pump running. If it were, the surge of pressurizing a zone may be causing the <35psi cut-in trigger within the first minute. Then, perhaps the pump never gets back to 50psi until ~8-9 minutes before the end of the zone and the last 8-9 minutes of zone run time doesn’t bleed the pressure tank to <35psi. When the zone ends it is in the nebulous 36-50psi window.

I think I’m giving myself a reason cough excuse cough to buy a digital pressure gauge and start logging data. I sort of wish I could force the well pump to bring the tank back to 50psi between zones running. I’d rather start at the top of the pressure window rather than the bottom and worry about under-pressurizing the rotor heads. The irrigation system doesn’t appear to have any pressure regulators on it. I’ve been thinking of buying some Hunter 45psi regulators.

Here’s the signature of my well pump from Sense while Rachio was running.

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Wow, very impressive. I’m with you that it’d be very informative to see the pressure data also. I have a very similar (maybe the same) architecture for my system (drip irrigation off of a well tank controlled by a pressure switch). I was getting a little concerned about cycling my pump and wondering if I needed to use a pump start relay. Your system appears to work well just operating off the pressure switch. I’m curious, can you say what flow rate your zones have and the size of your pressure tank?