My dedicated irrigation well pump has failed. The well company says it wore out prematurely because none of my six circuits was able to keep the pump (20gal/min) running long enough. The pump runs for 20 sec then shuts off for 20 then restarts. They recommend I gang several valves together (combine circuits) to get the consumption rate up so the pump cycles no more than once every two minutes. I have Hunter 1 inch electric valves and a Rachio Gen 3-8zone controller with two unused zones. I read here that ganging 3 zones together should be the max that I try. My question is: Can I wire a jumper from three zones to one of my unused zones but also leave them connected to their discrete zones with the appropriate diodes to prevent crosstalk. I would leave the individual zones connected to their discrete pins but add a parallel dc path to allow up to three to be actuated at once from a second zone control point. Question 2 what is the appropriate rating for the blocking diodes?
@jimrobx - I would recommend using SPST relays and a separate 24 VAC power supply to get around the Rachio limit. A Pump Start Relay (which you may have) will count as one and if the reduce water hammer feature is on (which I would recommend in your case to keep the solenoids activated when changing stations) will also count as an additional relay.
Hook the relay coil to the Rachio zone and C(ommon) terminals, with the separate 24VAC power supply on the relay common post. The put the zones you want run on the relay NO post.
Like @DLane said, you will need to set something up outside Rachio to tie additional zones together. You can do 3 zones (I have some of mine tied together), but that is assuming that you don’t have a pump start (which I assume you do), and you don’t have reduce water hammer feature (which you should to avoid dead heading the pump).
Not sure what a “pump start” might be. My pump has a large accumulator so pressure is always available even with all circuits off. I measured the valve output at the Rachio controller connection and got 7 Vdc @ 50 milliamps. I could build a simple circuit using 1 Amp 50 Vdc Schottky diodes (1N4001) that would allow groups of circuits (up to three) to be activated by one of the unused circuits without backfeeding any individual control.
Usually if your pump starts up when the controller fires a zone there is a pump start relay wired in. Basically it takes a low voltage signal from Rachio to a relay to send power to the pump. Sometimes, you can have a pressure switch setup, so when Rachio kicks on, and the pressure switch senses a drop in pressure, it will kick the pump on. I guess it depends if this is a dedicated pump for irrigation (most likely a pump start relay), or just a well pump (most likely a pressure switch).
If you don’t have a pump start relay, and don’t have any kind of master valve on the system, then yes, you can run up to 3 zones tied together with Rachio. Not sure if that will create enough flow to keep the pump from cycling or not…
The valves and controller output are AC. That means your diode “OR” logic will not work. A relay driving multiple zones is the proper solution
Thanks, had I only known.
Jim
Also… it just occurred to me that maybe your pressure tank is defective. I assume you have a pressure tank that allows for some volume of water to be delivered before turning on the pump. I suspect pulling more water won’t really change the cycling problem.
Yes I have a 20 gal air bladder accumulator tank. It was replaced two years ago and while it could be the problem, I doubt it because the 20 sec cycling was seen while the tank was brand new. The well company will test the tank on Tuesday when they install the new submersible pump.
Since the controller is powered by a DC wall wart it didn’t occur to me that Rachio would go to the trouble of installing a DC to AC inverter for the outputs.
I may be approaching this problem backwards. Perhaps I need to slow the delivery rate down and just run the circuits longer. The alternative is to combine circuits so the pump would run continuously. I don’t know if I can get to the 20 gal/min needed to make that happen.
@jimrobx the Rachio wall wart is actually an AC adapter. There are many posts where people have replaced it with a DC adapter and their AC valves don’t turn off.
You haven’t mentioned if you have a drip system or the what type and number of heads you have.
Maybe one day I’ll learn not to make assumptions. I measured ~25Vac at the outputs THEN I read the label on the plug in power supply, Sure enough AC to AC 125Vac in 25Vac out. Thanks for setting me straight. Looking for low current SPST relays now.
My system is mostly rotary nozzles with just a few fixed spray heads and no drips. Five circuits all feed through 1in PVC. My most heavily loaded circuit has nine Hunter rotarys, the lightest four.
Thanks
I’d still look at the pressure tank again even if new. The system should just not work that way. Biggest suspects are the pressure sensors that determine when to start and when to stop the well pump. If the low pressure sensor is set too close to the shutoff sensor pressure you’ll get exactly the behavior you see.
If you have a garden hose outlet plumbed near your pressure tank outflow just run a hose and see if you have the same issue…I’d bet you will.
One additional thought: a 20gal tank seems a tad small for any major irrigation system. We had a home previously with a well for irrigation and it had a 150gal tank. The smaller the tank the more frequently the pump will have to run.
Not sure what your pump output is, but I combined a bunch of my zones when I switched to the Hunter MP Rotators from spray heads. The massive decrease in PR allowed me to tie 3 zones together in 3 areas of my yard. My largest zone has 13 heads, and I still have 42psi at the furthest sprinkler, all running through 3/4” PVC. There still is a chance you could combine zones if your pump has enough flow to cover them.
I also tend to agree with this. I grew up on a well, and we had upgraded to a 150 gallon pressure tank when we started adding more irrigation around the house. I would think that for anything outside of normal household use, a 20 gallon tank is a bit undersized.
This issue sounds like short cycling. Essentially, your sprinklers are using say 10GPM, but your pump is trying to do 20GPM, and maintain pressure using the bladder. So sprinkler kicks in, bladder loses pressure over 20seconds and to the point it kicks on pump. Pump quickly fills up bladder to shutoff pressure and turns off, and cycle repeats.
You need a slower pump that more closely matches your consumption rate. Or you need a consumption rate that more closely matches the pump. The most universal answer would be a variable speed pump.
I think there is also a solution using a bypass valve, where once at pressure, the valve opens slightly and the pump just recycles water, allowing it to stay on. It may actually be possible to just use a dumb manual valve that accomplishes this if all your zones are the same flow rates.
I used jumpers on two zones to solve this problem initially. I decided to create a more global solution using SPDT switches and 4 pole dip switches for each zone all mounted on a prototype board. Each of the eight zones can be set to either follow the Rachio controller or instead connect to one of two “groups”. Independent to that each zone may be also be a “driver” to one or both of the “groups”.
