Master valve override

post by WokingWounded on May 23, 2017

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?!

post by DLane on May 23, 2017

@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.

post by WokingWounded on May 23, 2017

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?

post by Gene on May 23, 2017

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 prolonged periods without interruptions, you could use a 3-way light switch (link), or a remote system (link).

Switch would than toggle between having the master valve ON irregardless of what Rachio is doing, and having Rachio control the valve.

post by DLane on May 23, 2017

@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.

post by WokingWounded on May 23, 2017

Thanks Gene and DLane. I think I’ll try the simple solution first (ghost zone) and see how it goes.

post by DLane on May 23, 2017

@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.

post by Gene on May 24, 2017

Believe it or not, it is SC terminal which carries voltage relative to Common.

post by WokingWounded on May 24, 2017

Weird since the instructions imply the SC is the common terminal.

post by DLane on May 24, 2017

@gene - I should have never doubted you! It doesn’t matter which carries the voltage between those two.

post by WokingWounded on May 25, 2017

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.

post by synfinatic on May 26, 2017

So I also have a 300gal water tank & pump I use for irrigation. I bought two things:

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

post by jcduvall on May 30, 2017

Gene, I have a full bank of valve zones consumed, need to manually override the master valve while maintaining automatic Rachio functionality. 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?

Wiring Diagram

post by Gene on May 30, 2017

1. You will need a common wire going from one of the Rachio’s C terminals to the valve.
2. Yes, you can absolutely jump them at the receiver.

post by jcduvall on May 30, 2017

I was able to source the remote from your original post and I’ll wire it as we’ve discussed.

post by Gene on May 30, 2017

Unfortunately Rachio does not use/provide DC power externally. If your Rachio is installed indoors, it will probably be easiest to buy a separate 24V DC power supply.

post by jcduvall on May 31, 2017

I was able to source the remote from your original post and I’ll wire it as we’ve discussed.

post by bgreg on Jan 20, 2025

Hi Gene - thanks for putting all this together. Trying to find the recommended solution for Rachio3.

post by sandiaslice on May 3, 2025

This discussion was super helpful. I have a Master valve that I sometimes need to open by itself to pressurize a line going out to a remote box.