Master Valve only on specific zones

I am a little concerned about this, I switched from OpenSprinkler (which is $80 less) which had this feature. I am starting to regret it after reading this thread…I hope it happens soon, or will need to look at if I am able to return.

@rpw128 - how many zones need or don’t need the master valve activated as there is an easy way to accomplish this for a few zones using relays.


I attached a drawing (hopefully it’s visible). Essentially I expanded my sprinkler system as my yard has evolved. The supply lines to the front are PEX so they are better rated to have pressure all the way. The supply lines to my side yard are Poly (which my understanding is not “supply rated”) so I put a valve in front of it to “protect” it.

Depending on how troublesome the relay solution is I may just see if I can return the Rachio. As I see it, I lost a major functionality of my previous [OpenSprinkler] where I thought this would be an upgrade.

Appreciate the help and curious how much time and cost is involved to put a relay.

Looking at your schematic, it may be easier to simply connect Side Yard Supply valve (currently zone 5) to the master valve output (currently unused). This should make everything work. While the yard supply will be pressurized when ever any of the other zones are running, it should not actually activate given that you have individual control over the valves within the side yard box.

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Thanks for the reply. I did have it this way initially but I think from repeated pressure the Poly/PE pipe got pushed out of the valve and the box flooded (thus losing pressure to every zone).

I since reconnected with a new section of pipe, but fear it will happen again. It’s also just not good practice to keep pressurizing a section of pipe like that (considering exactly what happened to me…will happen). It’s exactly the reason I put a master on that section since I didn’t want to replace the whole line with PEX.

The relay solution mentioned by @DLane or switching the controller would avoid having to over-stress that section.

@rpw128 - For just two zones I would put in two Single Pole Single throw (SPST) normally open relays that would active the side yard master valve that is on zone 5. The relays are inexpensive, ~$7-8 last time I looked.

Here’s is how one would wire it up:

Zone 6 - two wires, one to the Lawn West and one to the coil wire on the relay.
Relay - other size of the coil wire to C(ommon)
Relay Common - 24 V- VAC (if you have a Gen 3, then I think you’d use the 24-VAC terminal and a Gen 2 I believe you’d use the SC (@Gene determined this is right one to use, instead of SP) - unless Rachio has changed things with the Costco version or an updated hardware.
Relay Normally Open Pole - output to the Side Yard Supply valve, can be combined together with the other relay pole.

Zone 7 - two wires, one to the Side Garden and one to the coil wire on the relay.
Relay - other size of the coil wire to C(ommon)
Relay Common - 24 V+ VAC (if you have a Gen 3, then I think you’d use the 24+VAC terminal and a Gen 2 I believe you’d use the SC (@Gene determined this is right one to use, instead of SP) - unless Rachio has changed things with the Costco version or an updated hardware.
Relay Normally Open Pole - output to the Side Yard Supply valve, can be combined together with the other relay pole.

For relay, look for one with a 24 VAC coil that is normally open.

As an example:

One can use a SPDT (Single Pole Double Throw) relay, instead of the SPST, just use the Normally Open and Common tabs (don’t use the Normally Closed tab).

Let me know if you have any questions, the wiring and relays are easy and will all be right there by the Rachio.


If the poly got pushed out before, it may be a good idea to get a few of these guys (link) from your local home improvement store (search for right size for the pipe, no need to get a whole set) and secure the ends well. Even with precautions, the pipe may come loose again if not properly secured.

What @DLane has described is a viable solution, but you would need to use 24-VAC terminal (instead of 24+VAC) in the configuration that he has described since Rachio Commons are connected to 24+VAC.

I’ve thought about using just one SPDT relay (similar to the one @DLane has linked to), here is the schematic to help illustrate the approach (zone 5 would be unused in this configuration).

In this configuration which ever zone is connected to NO terminal, also drives the coil. (in this example, it’s zone 7, but can be any other zone as long as it is connected to NO terminal).

@DLane’s approach may prove to be better, in case the two valves and a relay running off of one zone (as in with my version) draw more than 300 mA combined (at which point Rachio may start showing errors due to a high current on an individual zone).


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@Gene - thanks for catching my error buddy! (edited the original post)

And you would have to improve upon my design! While your design has just one relay, I was trying to KISS, by keeping everything similar and allowing for more than two zones.

To provide more detail for @rpw128 - zone 6 would power the side yard master valve when that zone is active as it is on the Normally Closed connection, no power to the side yard master valve when zone 6 or 7 is not running. When zone 7 fires, it would close the relay coil and power the master valve (zone 6 is NOT connected to the relay coil).


@Gene and @DLane

Awesome, thanks, I will give this a whirl for $8-10, appreciate the wiring diagram. I was going to put the worm clamp on but I realized it as soon as I pushed in the PE to the barb. Will need to snip it off and redo it though as it is a good idea.

Though seriously…this can’t be too hard to add the option to have Master on/off for zones in the software…

One question on the above design from @Gene, currently all commons are spliced together. Should I undo this for Zones 6/7 and if so where do they go?

Thanks again!

I do not understand why one would want a master valve to not effect specific stations. It defeats the purpose of a master valve. This is not possible.

@rpw128 - Keep all the commons together. You can put the additional common from the relay into the other C port.


@DLane is right. If you have an extra ‘C’ terminal available on Rachio, connect it to one of the coil terminals on the relay (polarity doesn’t matter). It also doesn’t matter which C terminal on the Rachio you use, as they are all interconnected.


@Gene and @DLane

I installed the relay today took me a little bit to figure out the wiring but it works.

When in doubt the software fails…find a hardware solution I guess!

Thanks again!


Glad it worked out for you. Post some pictures if you can, always great to see the end result.

Don’t forget to add some worm clamps, you don’t need to redo the hoses, just unscrew the clamp to be fully open, wrap it around the ends and screw it closed / tight again.


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Just wondering if anyone can help me figure out a wiring solution for my setup. I have 2 valve boxes. One for the main sprinkler system that runs 6 zones, one for the driplines in the back that runs 3 valves for my driplines. I have one of the 6 zones setup as a master valve as it supplies the secondary box. Currently this is set as the master valve and opens whenever a zone is running. This works but obviously is not ideal as it is poly pipe with blu-lock fittings and will eventually fail due to constantly being pressurized.

What I am thinking is to use 3 of the SPST relays attached to the 3 dripline zones to also activate the 1 valve used as the supply. I am unsure how to wire this so that it is not running 2 valves off of each of these zones at once. Can anyone give some guidance?

As a sidenote, I really wish they would add the feature to select the master valve per zone as they said they would. This would solve this issue without the need for any addon solutions. It seems like it would be simple as the logic and code already exists as the master valve can be selected/deselected in the controller settings. Just add that same routine to the zone routines and expose it to the user. This is a highly sought after feature and there are endless requests for it on every controller manufacturers forums including this one.

@noahdare - welcome to the community. The 24 VAC SPST relays that I’ve found on Amazon don’t pull much current, so there should be no issues with running them and the zone valve.

So - zone 6 = master valve and 7, 8 and 9 are the drip valves.

  1. Disconnect the zone 6 wire from the Rachio master valve terminal.

  2. Connect one side of the SPST relay coil to the Rachio terminal 7 along with the solenoid valve.

  3. Connect the other side the SPST relay coil to the Rachio C terminal (all the relays can be wired together and just one wire put into the terminal).

  4. Connect one side of the pole to the zone 6 wire (all the relays can be wired in parallel to this solenoid) .

  5. The next step depends on which generation of Rachio that this is being connected to.
    For Gen 3, connect the 24 VAC + to the other side of the pole on the SPST relay (again all the relays can be wired in parallel and only one wire needs to be in the Rachio).
    For Gen 2 connect the SC (sensor common) to the other side of the pole on the SPST relay.

Let me know if there are any questions.


I think I understand what you are saying. So the wire coming from the “Master valve” is connected to one side of the pole, with the other side of the pole in the 24 vac connector on my gen3. My confusion though is, what serves as the common then for the master? When the relay is activated by power from 7, does it just go to the common on the coil?

@noahdare - the common for the “master valve” will still be the C terminal on the Rachio, where it is currently connected.

So zone 7 fires both the solenoid for zone 7 and the SPST relay they will both return through the C terminal. When the SPST relay closes (I should point out the relay should be Normally Open - NO) the current from the 24 VAC + will flow out to the “master valve” and then back via the C(ommon) terminal.


duh. I wasn’t thinking that through completely, obviously. Thanks for clearing that part up. Ordered the relays and am going to give it a shot.


Spent Sunday afternoon getting things hooked up and it works great. Thanks for the help DLane. Went with the Packard relays, they do have quite a noticeable buzz when they are active. But they are in the garage and in an enclosure so it isn’t too bad.