Rachio 3 convert from Hunter Pro-C - Master Valve

Hello all, I hope this isn’t a duplicate, but last year we moved to a new house and left our old Rachio 3 behind for the new owner. After a few weeks of dealing with the new system, Hunter Pro-C, I realized I needed to get back to Rachio so I purchased the Costco 12 zone Rachio 3. I took lots of pictures of the old setup before installing the new Rachio and everything is working fine. Now, I am considering adding a drip zone for my garden to take up one of the three remaining unused zones, and I have run into some questions…

The old Pro-C unit had a wire connected to the MV “post”, so I connected this to the M slot on the Rachio, but in the app under Controller Settings->Advanced Wiring, I have “Neither” selected and the system runs just fine. Does this make sense?

I’m going to try and trace the wires this weekend to see if I can find the valve that is connected to the “M” wire, and will report back what I find. So far I’ve started at the backflow preventer near the main supply valve and worked my way through the yard (approx. 1 acre), but have only found about six of the nine valves, one of which could be the master(??). The possible master is near the controller, and in a box with another valve. All other valves I have found are single box/valve setups.

In the end, I am hoping to tap into the main water supply for the irrigation system, and plumb in a line to feed the drip system, and control the new drip zone with a new valve.

Any help would be greatly appreciated.

It’s possible that the master valve has failed and is stuck in the ON position.
Or original installer thought of adding one, and never gotten around to it.
Ideally you’ll find and repair the MV, or install it if you’ve never had one, as having two valves in series greatly reduces a chance of a large water loss / flooding.

If the valve is stuck / missing, using common tracing methods would not work. Your best bet is to see if you can identify the wire colors within the bundle and find out which valve is which.

Thanks Gene. That is a great thought. I’ll look into that. Stupid question, but would it be visibly noticeable if a valve were stuck open?

Unfortunately, when I open some of the valve boxes, I see what looks like 18 gauge, colored, six (?) wire cable and some heavier gauge red and white wire. At the controller, all of the wires are the red larger gauge wire with the common, larger gauge white.

I have a Klein toner that may work to at least trace the “M” wire to its’ destination. We are in central Texas, so the lines are not very deep. Most of the nuts and bolts of irrigation install are new to me, so figuring out the whole of the system is going to take some time.

@JM-64 - If you have a multi-meter (AKA volt/ohm meter) is there any resistance down the wire on the M (FKA MV) terminal and back on the C wire. I would disconnect the M wire from the unit before doing the test so there is no backfeeding of current.

I was planning to disconnect the M anyway to for some of my testing…
My thoughts for testing are:

  1. Disconnect M and see if the system will run. If there a master valve is wired, but maybe stuck open as Gene suggested, will it run without the option checked in the app, as it is now?
  2. Disconnect M and use my toner connected to M and grounded to a metal stake. See if I can trace it. I would think I should at least be able to get a tone inside the valve box on the commons and whichever colored wire leads to M. Might even be able to trace at ground level??

Using the tracer, I may be able to pick up the common wire and locate the “missing” valve boxes. I also have a very good metal detector that may be of some value.

As far as I know, MV needs to be enabled via app to activate during runtime.
Do all of your nine zones activate right now?

Yes sir, system runs two days per week. This morning it began at 2:36am, ran all nine zones (some twice ?), and ended just before sunrise.

I’ll need to review my settings, but I’ve read that various settings will cause some zones to run twice, for soaking in.

Ok, not sure this helps, but I disconnected M and toned that wire, with a ground to a spike in the ground. Gene, I think I see what you’re saying…every wire has tone. I expected that for the common, but not others. Jlk

Regardless, by the water meter there’s a large bagged back flow preventer, then immediately a valve box. It has two wires coming in, tied to the valve, and they have tone.

If there’s a master that has to be it, right?

With M disconnected, I tested a zone, and it runs fine.

I think Gene is right, master stuck open. Need to test and repair as needed. Any other thoughts?

Another dumb question…
Once I get the master working:
If I tap the feed side of any valve as my water source for my drip zone, add a new valve, and wire to common and new zone, will that work for a second, new “drip” schedule?

Yes, any schedule you add should activate the MV in case you get it working.
Photos of your backflow preventer and the first valve box may Shead some light into the situation.
You should be able to turn on individual valves by turning the solenoid about a quarter turn; should you find a valve that doesn’t seem to do anything, it’s likely your master (being stuck open).
Good news is that you should be able to replace functional part of any valve by finding a similar model in a home improvement store (hopefully yours are not too old to be a special order), replacing everything but the valve body should be as simple as unscrewing a few screws, lifting the old valve out and putting parts from the donor (new) valve back in.

Valves are solenoids, essentially inductors, aka a coil of wire. This is why you are likely getting your signal spreading to Commons and thereby to any other wire. You could try disconnecting the valve you’re testing to see if signal stops at the disconnect.

Thanks Gene!
To the best of my knowledge, the system was installed in 2016, but it does seem to be a bit of mix and match Hunter, Rainbird, etc. I like the idea of disconnecting the valves, as that may help me trace the path of wires between valves. I still have a few valves to find.

I’ll get some pictures of the backflow preventer and post them.

I hope the the picture comes through and makes sense.

Right to left after black meter box, ignore the the concrete plus valve boxes, those are water supply Co.

  1. Looks like a valve, or diverted of some sort.
  2. Another valve, lead free, probably main house supply.
  3. Ahead of backflow preventer, valve
  4. Backflow preventer
  5. Master irrigation valve? wired as described.