Master valve override

My watering system is fed by a 2000 gal rainwater gathering tank. It has a pump and a master valve. The Rainwater circuit also feeds garden taps (for hoses etc) so I need to be able to switch the master valve on manually. Because the master valve is remote from the controller it’s a pain to manually switch the valve on and off. Is there a feature in the Rachio app that allows one to open and close the master valve without opening any zone valves? Failing that has anyone tried wiring a physical switch local to the controller which achieves the same - and can provide a wiring diagram?!

@WokingWounded - my first reaction is do you have a spare zone on your existing Rachio controller (e.g. only using 7 zones of an 8 zone unit)? If so, I’d set up a phantom zone which isn’t connected to anything and have that zone not set to run. When one needed to use the garden taps then the phantom zone could be run using the manual remote in the application for X minutes. Its early so I may not have thought through all the pit falls yet - like I said my first reaction to the problem.


I hadn’t thought of that! And yes, I will have spare zones (I’ll need no more than 12 of the 16 available). It means that the master valve would be connected to the master valve circuit and to the ‘ghost’ circuit - would that cause problems/interference? Hang on that’s rubbish, the ghost circuit would switch on the master circuit so the master valve only needs one connection but the ghost circuit would be connected to nothing. Possible problems might be the Rachio’s reaction to switching on a disconnected circuit - would it throw up an error/fault message? Is there a limit to the ‘on’ period when manually starting a zone?

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Ghost circuit should not result in any errors as far as I know and you can run it up to 3 hours at a time. One problem is that if you have an option turned on to minimize run-off (meaning that zone will partially water, pause and water again), you will get “dead” periods within your runtime.

If you need your master valve active for a prolonged periods without interruptions, you could use a 3-way light switch (link), with the outdoor enclosure, or a remote system (link).

If using a 3-way switch, connect one wire from M terminal to one of the brass (shiny mental) screws and SC terminal to the other brass screw. Master valve would than connect to the black screw and you could optionally connect earth ground to the green screw (though this should not be needed, since we are dealing with relatively low voltages).

Switch would than toggle between having the master valve ON irregardless of what Rachio is doing (by connecting SC and Mater valve), and having Rachio control the valve (by connecting M and Master valve).

With the remote, you will need to connect SC and SP terminals to AC/DC terminals of the remote (which one is which does not matter). Master valve wire would than connect to one of the COM lines, M terminal to NC terminal next to the COM terminal you’ve used and SC should be connected to NO terminal next to the COM. (you should be using either 1st port, or 2nd, not both).

Let me know if you have any questions, I can make a wiring diagram if you need it, but don’t want to spend the time if the phantom zone will be your preferred solution.


@WokingWounded - the ghost/phantom zones won’t cause a problem with the Rachio. I’ve got an eight zone version, but my yard only has four solenoids. I set up the four unused zones to play around with daily flex on specific days and any day. So I’ve got all eight zones configured in the application, but only four hooked up to actual solenoids.


Thanks Gene and DLane. I think I’ll try the simple solution first (ghost zone) and see how it goes. Sadly the requirement for a hose tap is entirely my wife’s (I’m the cook not the gardener!) so it will not be my decision as to whether this proves satisfactory. The three way switch should also work although I’m not sure about the wiring. If the master valve is connected to either M or SC depending on which way the switch is flipped, and the other valve terminal is connected to C, will this work with the C/SC pairing (aren’t they both common wires and therefore on the same side of the power cycle phase so no potential between them)? I can see it’ll work with M/C connection.

@WokingWounded - I’d do the KISS option first. On the three way switch, I think @Gene may have meant the SP (Sensor Power) instead of the SC (Sensor Common) port. When the switch in the the M position the Rachio will control the pump and when the switch is in the SP position it will run.

Believe it or not, it is SC terminal which carries voltage relative to Common, I’ve made mistake thinking that it was SP terminal in the past. Someone can verify with AC Voltage meter, but @franz should be able to confirm one way or another.

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Weird since the instructions imply the SC is the common terminal when installing sensors. I’ll check with my multimeter when I install. Thanks to everyone on this. I’ve just received the unit from Amazon but am waiting delivery of a 240/24VAC transformer since the supplied 120/24VAC unit is no use to me (I live in the UK). In the meantime I’m getting a lot of the forward planning done!

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@gene - I should have never doubted you! I would have lost money on that bet all day long. It doesn’t matter which carries the voltage between those two, only when one is jumping over to the zone/pump common does it matter. A multi-meter won’t lie. I hope Rachio didn’t realize this and fix it midstream in the Gen2 line - if so, hopefully there will be an easy way to identify which port is carrying the voltage.

At least now we have this documented in the community board so that hopefully someone having a similar problem will stumble across the answer.

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OK! I’ve installed the Rachio and set up a ghost valve. Works fine but I can’t see how to set it going without setting a duration - with consequent “range anxiety” as they say in the electric car world. So I installed the two-way switch master valve override. Works a treat…but clearly once it’s switched on no-one remembers to switch it off. So what I’m going to do is install a mechanical double throw solenoid switch (cost £5 on Amazon - about $7) which is just like a two way switch except it’s sprung so that the output terminal is normally connected to the NC terminal (Normally closed) except when the solenoid is energized when it switches to NO. NO will be connected to SC, NC to M (as described by Gene) and to energize the coil I have a spare z-wave switch which can be operated either by the local wall switch or through my VERA z-wave controller. I can then include the z-wave switch into the logic which automatically switches off my water features in the late evening so that the master valve reverts to being controlled by Rachio in the evening if it has been overridden during the day.
By the way I checked the SC to C pair with my multimeter and get 27VAC; SP to C gives nothing - good call Gene!


So I also have a 300gal water tank & pump I use for irrigation. Obviously, you don’t want the pump to run when the tank is dry. So I bought two things:

  1. A float level switch to detect when the water level was low
  2. A delay timer like this one:

I installed the float level in the tank slightly above where I want the pump to turn off. You just want it a little bit because these switches are really sensitive. Hook up the float switch to the timer and the timer to the pump relay. You continue to use the master valve to control the pump.

Then you can tune the delay so that you don’t have the pump quickly cycling between on and off when the water level is low enough to trigger the switch. At least in my tank, running the pump caused enough water movement in the tank that the switch would tend to quickly turn off and on the pump when the water level got low enough. The delay timer effectively keeps the pump running for another 30sec so the water level drops enough to keep the pump turned off but not long enough to run the pump dry.

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I have the same need… I have a full bank of valve zones consumed, and need to manually override the master valve to operate a hose bibb while maintaining automatic Rachio functionality for the rest of the zones. A couple questions to your post if I go the remote switch route:

  1. Do I need to still have a wire going directly from the M terminal to the M valve?
  2. If I need to have SC terminal to both AC/DC and NO on receiver, can I just jump them at the receiver?

I have a wiring diagram attached - so basically do I have it correct and do I need the pink line?

Thank you for your assistance,

Great diagram :slight_smile:

  1. You will need a common wire going from one of the Rachio’s C terminals to the valve. You may have already connected it when you connected the rest of the zones (if your master valve is working with standard zones, your common is already hooked up). You do not need a separate wire going from the M terminal (colored pink in your diagram).

  2. Yes, you can absolutely jump them at the receiver. You can get rid of the black cable as per your diagram.

Cheers :cheers:

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Excellent - thanks for the quick response and additional details. I do have a common already hooked up to all zones and the master, it is currently working! I’ll jump the NO and AC/DC and be ready to go!

Thanks again!

By the way, what remote are you using? From your diagram, it almost looks like it needs D.C. Voltage, not AC provided available from Rachio.

It’s an eMylo DC 24V 1 Channel… will the Rachio provide the needed DC from the SC/SP terminals? Or do I need to look at a different remote?

Unfortunately Rachio does not use/provide DC power externally and rectifying the AC voltage Rachio does use would result in higher than 24V DC voltage (thus unsuitable for your needs).

If your Rachio is installed indoors, it will probably be easiest to to buy a separate 24V DC power supply. In any case avoid connecting SC terminal to the negative power input of a DC remote, try looking for something with AC input capability.

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I was able to source the remote from your original post (link) and I’ll wire it as we’ve discussed. Thanks for the detailed review and assistance! Now, I’ll just have to hide the remotes from my kids! :slight_smile: