Zone 1 activates for 5 secs when I start other zones

Hi all,

I have an 8 zone system w/ relay pump (well)… everything worked upon first boot up, but for some reason zone 1 pops up/waters for about 5 seconds each time I turn on any other zone (2-8).

Any ideas why? (I don’t recall this happening before).

note: Only diff between wiring in my old Hunter xcore is that all 5 common wires were in the only “c” terminal of the xcore, but since Rachio3 has 2 “c” terminals I put 3 common wires in one “c” terminal & 2 common wires in the other “c” terminal.

@Adrian97c - My initial guess on those symptoms it the valve on zone one may need servicing. A quick way to test that is to either disconnect zone one or swap zone one and zone 2. If the behavior is consistent then the issue isn’t electrical but mechanical in that valve/diaphragm. If the behavior isn’t consistent or moves to zone 2, then we’d need to dive into it a little bit more.


@DLane I’ll try that out first before anything else.

Irrigation is 5 years old, but I didn’t install it… So there will be a learning curve if I end up needing to “service” the valve.

Thx for providing troubleshoot direction! I’ll report back after I try disconnecting zone 1 from rachio controller.

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Ok, I disconnected zone 1 from controller & disabled it from app… the results are the same, zone 1 still bubbles up when starting up any other zone.

So what exactly do I try next at the valve box? I believe it’s all hunter brand valves/solenoids (or whatever they’re called). YouTube how-to links is what I’ll use per whatever instructions you give me.

Thx @DLane &/or anyone else that can guide me on this.

I’m with @DLane on this one, sounds like you have something interfering with the diaphragm within the valve or the pathway pass the solenoid. There are plenty of youtube videos (like this, or this one) which show how to take apart / inspect the valve, but first I would try completely removing the solenoid and letting water flush out any debris for 15 - 30 seconds. If after flush, your zone 1 does work as expected, than it is worth taking apart / inspecting the diaphragm within the valve. Finally, should all else fail, you can purchase a similar Hunter valve and replace the guts using similar steps to cleaning, simply remove old parts & install new. This way you would essentially get a new valve without dealing with cutting out & installing the valve body.


Awesome! I will have to dig up the valve box, damn moles packed dirt upwards.

I’ll watch the videos in the meantime, then sometime next week (or sooner hopefully, lots of rain currently), I’ll dive in & start the tinkering.

Once I get this fixed, I’ll be installing one of those wireless Rachio flow sensors to help keep an eye on any future issues.

I’ll post back here, thx @Gene!


While it may be common sense, I’ve mentioned this to friends of mine, and you’d think I just told them about the concept of gravity…For servicing valves, I highly recommend finding the same valve, that way you can just unscrew the top bonnet piece, and replacing not only the diaphragm, but also the top bonnet and solenoid. Usually the cost of the whole valve is about the same as just the solenoid and diaphragm if bought individually. I have never had to replace a body of a valve, but I’ve had multiple bonnets get hairline cracks in them…


I’ll stop in at Home Depot and grab a hunter PGV valve, $17. It’ll be worth having it on standby, even if flushing old one fixes the issue. Thx for the recommendation. Hoping to have this resolved so that I could install Flow sensor & finally be all done with my Rachio upgrade.

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Same valves I have. 4 Screws and the top pops off. A quick 5 minute job! Grab some waterproof wire nuts while you are there so you can wire in the new solenoid.


@tmcgahey @Gene @DLane

Interesting development, while I went ahead & bought a new valve, I was able to fix the issue without swapping anything out!

This could be only a temp fix, well will see, but at least I have new valve ready to go as a backup.

Here is what I did:

  1. loosened the flow control knob on zone 1 valve.


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When you say loosened, did you do that by turning the knob clockwise (CW) or counterclockwise (CCW)?

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Glad you asked, because I’m unsure! Plz look at the video I made:

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Also here is the end result:

Great video :+1: so to recap the chain of events as I understood them

  1. First you’ve turned the flow control clockwise, thereby restricting the flow and increasing pressure required to activate the zone (thus solving your initial issue).
  2. You then turned the knob in the other direction (CCW), thereby increasing maximum flow. Going to the point where the valve started leaking. This does not appear to be due to an excess pressure at the inlet, but simply a design of the valve (they’ve forgone putting in the limiters in order to save costs).
  3. You’ve flushed the diaphragm chamber (which never hurts to do when troubleshooting the system).
  4. You’ve again added some flow restriction by turning the knob CW, thereby returning the valve from an open (leaking) extreme. You again seem to have passed the point at which zone would turn on by itself.

Thanks for sharing your experience :man_scientist:, flow adjustment is a good troubleshooting technique which will definitely go into community’s bag of tricks :wink:

One thing to be on the lookout for is that excessive flow restriction may prevent a full coverage from your sprinklers. When you get a chance, just run zone 1 again and make sure that the spray radius is sufficient for your needs. Here is a video (link) which goes more in depth for this feature and shows a recommended procedure of how to make an adjustment.

P.S. Great showcase for Rachio’s Alexa support with your second video, music is great too :sunglasses:


Thank you for helping me understand & correcting my explanation of CW (limiting flow/increasing pressure), CCW (increasing flow/decreasing pressure)!! Makes sense now!

Learned a lot from this!


After some tweaking with the same knob, I went back to try Zone 1 again, ran it & the 5 pop up sprayers didnt lift up enough to spray, so I went back & forth to dial in the right amount of flow/pressure at the valve. Now it runs when it’s supposed to & doesn’t dribble at the heads when other zones start up. :smile: (Glad you mentioned that!)

What still confuses me is (due to my lack of understanding how irrigation/plumbing works :brain:):

  1. why was this happening only upon starting other zones, issue would only last few secs (not entire time other zones ran)?

  2. why is Zone 1 even receiving water flow if running a diff zone? (Normal? Or indicating a valve malfunction?)

  3. only thing diff between Zone 1 & all other 7 zones are that zone 1 heads are the fixed pop-up kind (for shrubs). Are the fixed pop up sprayers (non rotating) more sensitive than the rotating ones?


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An irrigation valve normally has five major parts: an inlet and outlet chambers, a diaphragm chamber (d.chmb), a solenoid and a spring which provides additional closing pressure onto the diaphragm. There are also two small vents (openings); one (input) which connects the inlet to the d.chmb and a second one (output) which connects d.chmb to the outlet through the solenoid (whereas solenoid can block the opening while off and holds it open while on).

This configuration normally allows two configurations: While valve is off, the output vent is blocked and input vent allows d.chmb to equalize with inlet chamber. This, in turn, allows the spring actually exert enough force to close the valve. While the valve is on, the output vent is unblocked allowing the water to flow through the d.chmb freely thereby reducing pressure relative to the inlet chamber. As soon as the pressure difference between inlet chamber and d.chmb is greater than the force exerted by the spring, valve opens up and continues to operate until output vent is blocked and d.chmb pressure is equalized with the input.

I believe that the reason for 5 second issue you’ve experienced is that you are using a well pump, meaning that there is a period of time whereas irrigation pressure is constantly increasing while the pump is ramping up. Due to the size limitation of the input vent the pressure within d.chmb will be lower than the input chamber until sufficient time to equalize has passed.

As far as I know, the flow control on your valve is connected to the spring that provides a closing force. The more flow control turned in a CW direction, the stronger that spring becomes (the knob turns the screw which, in turn, pushes the spring harder against the diaphragm). Pushing the spring tighter against the diaphragm allows you to essentially overcome the pressure differences during the pump startup.

It is possible that the flow control screw on that particular valve became loose with time, or something got stuck in the input vent thereby increasing the time d.chmb would take to equalize with the input. It is also possible that it is simply a question of proximity of the valve to the well pump.

Here is a better video on how the valve works, in case I confused everyone :wink: