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RCO Single-Wire Dual-Zone Control | ADD-A-ZONE

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Sale Price $136.95
Our Price $280.35
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RCO Single-Wire Dual-Zone Control

  • Adds a new zone without the wires
  • Capable of fixing water pressure issues with additional valve
  • Also allows you to go around faulty field wiring
  • Simple to install

Introducing Add-A-Zone, the convenient unit that eliminates the need to add wiring when adding a zone. Use it to add additional valves to a system to correct water pressure problems. Or use it to work around faulty field wiring. Unlike other "switching" units, the Add-A-Zone behaves just like the valves are fully independent. You set the individual run times for 2 zones on the controller just like you regularly would and Add-A-Zone works "behind the scenes" to make it happen. Maximum control and flexibility that installs in minutes.

Features & Benefits

  • Both valves connected to an Add-A-Zone are independently timed and activated from the controller for both manual and automatic operation
  • The 2 valves can be assigned to separate watering schedules and programs in the controller
  • Permits easy addition of an additional valve to controllers with spare stations without the need to divide out a run time on a single zone or activate the new valve every other watering cycle
  • Makes adding a valve to correct water pressure problems easy
  • Broken wires can be abandoned and worked around without loss of programming flexibility
  • Fast and inexpensive to install
  • The added valve can be a master valve
  • Operates on most 24-Volt sprinkler systems
  • Switching capacity: 0.5 A
  • Life Expectancy: 50,000 operations

Product Details

Installation Instructions

Adapter Part B (Install inside valve box)

  1. Connect Blue wire to one valve.
  2. Connect Brown wire to second valve.
  3. Connect White wires to existing common wires.
  4. Connect Orange (active) wire to existing field wire.
  5. When in operation the Green LED will light up when station 1 is powered and the RED LED will light up when station 2 is powered.

Adapter Part A (Install inside controller cabinet)

  1. Connect Blue wire to existing station output.
  2. Connect Orange (active) wire to existing fi eld wire.
  3. Connect Brown wire to the unused station output.

Related Articles & Videos



Single-Wire Dual-Zone Control
1 year
Product Type:
Single-Wire Dual-Zone Control
4.5 / 5.0
34 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Works very well
As an irrigation repair specialist, I keep these on hand for situations where a sprinkler zone wire has died and finding the fault proves to be difficult. It's less expsnsive than running new wiring, and a lot less labor. This product is easiest to install when a pair of valves are in relatively close proximity, and allows two valves to run on a single pair of zone wires. A chief advantage of Add-a-Zone over Valve Doubler is that the zones continue to run in the same order. With some other brands, the switch reverses the order of zones 1 & 2, for example, if you try to run zone 1 twice in a row. Zone 1 becomes zone 2 the next time. With Add-a-Zone, you can run zone 1 as many times in a row as you like and it's always zone 1.
March 24, 2014
over 4 years ago
Easy to install
Easy to install. I had to change a 3 zone module to a 6 zone, but that had nothing to do with the Add-a-Zone. I was adding a zone. The Add-a-Zone did exactly what I needed. A new independent zone. Perfect.
July 9, 2017
over 3 years ago
Works Flawlessly
Used to Add-AZone to repair zone not working due to wiring issues. Very easy to install.
January 21, 2018
over 2 years ago
Installation detail
The instructions are easily understood by anyone with electrical knowledge.. a more detailed diagram depicting each wire and where it actually goes would be helpful those with less knowledge... there is an assumption that all wiring is accounted for, when in fact it is not.. good product when installed.
July 1, 2017
over 3 years ago
Great Product - Really fast shipping
Im a homeowner - DIY guy who had his system updated and improved by a Pro about 10 or more years ago. That pro Added a zone using a previous generation Add a Zone. I replaced it this week while making other updates. Im not certain that it was dead but since I was replacing the timer and some solenoids I wanted to get everything set for more years of work. The new one comes with a multicolor LED to indicate which zone is activated and that you infact have good voltage and wires to that point. The LED is Great for troubleshooting. FYI the new Add a zone looks different than the image here.
August 15, 2014
Great product and Time Saver. Easy-to-follow instructions. Definitely well worth the price that you save in time and labor.
June 30, 2017
over 4 years ago
Awesome Device
If you have unused zones on your sprinkler controller, this the Add-A-Zone allows you to add one zone, without needing an extra wire. The new zone is fully controllable, the same as your original zones. I used 3 of these to add 3 zones.
September 12, 2017
over 3 years ago
They work
It works as it's supposed to, I've got a few in service and they haven't failed yet
April 14, 2018
over 3 years ago
Worked great, my valve was about 60ft away from an indoor controller. I'm not sure what the signal range is, so others may want to consider that when purchasing
August 17, 2017
over 3 years ago
Great product!
Great product. Installed this today and it does exactly what it says it does. Installation was very easy. This is definitely the way to go if you don’t/can’t run a new wire.
May 31, 2018
over 2 years ago
Start typing your question and we'll check if it was already asked and answered. Learn More
Browse 33 questions Browse 33 questions and 121 answers
Why did you choose this?
SprinklerWarehouse.com Store
Need for a project
B O on Sep 27, 2018
Broken sprinkler wire under concrete
T E on Aug 3, 2018
Need for a project
B O on Sep 27, 2018
S U on Aug 16, 2018
Broken sprinkler wire under concrete
T E on Aug 3, 2018
I have a cut wire that cannot be found. Rather than doing a lot of digging I'm going to add a zone.
Brenda G on Jul 31, 2018
needed this product
R A on Jul 28, 2018
needed to activate a valve without a separate functioning wire to make it work
L A on Jul 8, 2018
It appears to meet our need and the price seemed reasonable.
T U on Jun 18, 2018
looks like what I need
B C on Jun 14, 2018
recommended by sprinkler repair company as inexpensive alternative to running new wire
B A on May 23, 2018
needed to add second zone
patricia w on May 23, 2018
I have a broken wire between the house and the valve. This will prevent me from having to run a new line out to the valve.
P A on May 8, 2018
converts one wire into two fairly easy, expect about four years of life out of it. its best to run a new wire but when you can't use this.
L I on Apr 26, 2018
Recommended by sprinkler repair person. Best price!
Sharon R on Apr 23, 2018
This is what I need.
R O on Mar 19, 2018
To replace an old add a zone dual zone.
S T on Mar 14, 2018
No extra wires run to valve so I would have to either use one of these or run 150' of wire.<br />Installer let me down.
William K on Mar 2, 2018
Read many good reviews about Add A Zone control.
G R on Dec 19, 2017
Great product and easy to use
Mark S on Dec 19, 2017
My contractor used a five wire cable for a five zone set up, now that I want use the fifth zone I have to use this system. I chose this over a battery operated controller so my rain sensor would work.
Ben D on Oct 20, 2017
wire failed
Guanghua D on Oct 14, 2017
to replace
P O on Oct 10, 2017
To replace a competitors device for adding an additional zone that had failed.
A D on Oct 1, 2017
previous use/price
L E on Aug 4, 2017
Looks like a good option for a failed single wire in bundle from controller.
Bruce M on Jul 20, 2017
Need fix for sprinkler system without having to find wire that is not working.
T C on Jun 7, 2017
Fixing a broken wire issue
Erik J on May 7, 2017
For the reasons stated on the website.
Kenneth S on Apr 26, 2017
perfect for my problem
T C on Mar 17, 2017
S U on Aug 16, 2018
I have a cut wire that cannot be found. Rather than doing a lot of digging I'm going to add a zone.
Brenda G on Jul 31, 2018
I bought a new time and didn't know the add-a-zone was in use and accidentally threw away the "Part A" that combines the signals at the timer. Is Part A available separately?
David D on Feb 2, 2013
how well does this work?
A shopper on May 29, 2011
BEST ANSWER: Add-A-Zone is fantastic for three reasons: stations combined one a single control wire do not have to be separated by a gap so the device can sense a power drop and switch, stations can have different run times, and a station on the controller ALWAYS comes on in sequence. With the "Doubler" devices, there has to be a break in electrical power to cause a switch. Unless the controller can be set up to put a pause between stations, the most common tactic is to combine, for example, stations 1 and 3,, which may not fit the sequence you want. Since the Double just blindly switches back and forth, it can get out of position. Say the controller runs OK past the first station and gets stopped before it runs the second station. The next time it runs, the second station will run first. If station one is set for 5 minutes and station two is set for 20 minutes, now they are running exactly backwards. One is drying out and the other is flooding. I LOVE this product.
how do you hook the add a zone up?
A shopper on Jun 1, 2017
BEST ANSWER: Downloadable manual is incorrect.
Instruction manual (card) that comes with the product is correct. Instructions are easy to follow.
Great product, in use for 2 years and no problems.

Revised instructions:
Adapter Part A
(installs in controller cabinet)
1. Connect Brown wire to one station output.
2. Connect Orange wire to value wire running to timer or controller
3. Connect Blue wire (manual says Black wire) to the second station output. Try not to connect brown and blue wires to adjacent terminals, have one other terminal between the two.
Adapter Part B
(install in valve box)
1. Connect orange wire to existing zone wire.
2. Connect White wire to existing common wire.
3. Connect Blue and White wire to the first control valve.
4. Connect Brown and White wire to the second control valve.
I bought two of these and they seem to work as advertized. However, when in operation, the smaller module that is located within the control unit becomes very hot. One of them is actually starting to swell. Is this normal? I have a Hunter Pro-C control unit and the modules are not near any of its components.
Paul C on Jul 11, 2013
BEST ANSWER: I do not think that it is normal for the small module to become hot. I have six of these units installed on a Hunter controller and I have never experienced that problem although I have never touched a small module when a valve was operating because my system runs at night. I suspect that you have a short in the line or a bad solenoid that is causing that circuit to draw too much current. Try measuring the voltage on that circuit while it is operating and see if the voltage is significantly lower than 24V AC which would indicate a short in the circuit.
The Add-a-Zone was working as expected for several months, but now my original zone always comes one when any other zone is on. To be more specific, I have an 8 zone controller/timer, and zones 1-7 were in use. I installed a new valve (zone 8) next to zone 4 (denoted as "original zone" above) and that is where I used the Add-a-Zone. Any ideas? It seems like a wiring issue but why would it have worked for 3+ months?
Brian D on Sep 30, 2015
BEST ANSWER: Check the timer with a solenoid at each zone. So turn on zone 1 or the one you have the relay on. Then check all of the other zones. If you only have power at that zone only. Then it's the relay.

I have a jobsite with a 15 station controller, all stations are in use and I need to add one more station will the ADD-A-Zone work for me?
richard t on Jul 27, 2015
BEST ANSWER: No. Add A Zone is to add another zone to a controller with open stations but no extra wires in the yard. It runs two valves (stations) off one wire.
Can I use a add a zone in a rachio controller?
A shopper on Mar 28, 2017
BEST ANSWER: This add a zone works with most all controllers with 24 volt output. I am not familiar with a Rachio model but should not matter. This add a zone allows you to add a zone/valve where you only have one single wire to an existing zone in the field, thus this devise comes in 2 pieces- one in controller and one in field so the original single wire will now operate 2 separate valves
is Add-A-Zone device waterproof?
R O on Mar 21, 2018
BEST ANSWER: It is waterproof. I have two installed and they have been working two years even in the heaviest rain. They should be installed in a valve box but they will work even if the box gets flooded.
Ok, I have read the comments but just want to make sure.

I have a situation where the irrigation installer set up multiple junction boxes between the valves in question and the controller (distance about 200'). Between two of the junction boxes, I do not have enough spares to add any more zones (I have the spares in junction boxes on either side of the one link). I was planning to use the Add-A-Zone to increase the number of zones between the two junction boxes (and not at the valve). Will this work?
MikeS on Apr 13, 2014
BEST ANSWER: I'm not sure that I fully understand your setup, but keep in mind that the Add-A-Zone accomplishes what it does by opening and closing an additional VALVE using existing field wiring to an existing valve. What you get when you buy this product is basically a transmitter (of sorts) that installs in your sprinkler control box and ties to an existing circuit wire. The other piece is a receiver that will need to be jumpered off of the valve at the end of this same existing circuit. You would need to install a new valve for the new circuit and wire according to the instructions. You also have to be sure that your controller has room for this new circuit. All this product does is to allow you to install a new circuit without running a field wire out to the new valve box. There is nothing else that it does for you. Hope this helps.
Is the add-a-zone device waterproof? The box where the unit will go sometimes has water that comes into it and can make this device be underwater for a period of time
Andy F on Jun 30, 2015
BEST ANSWER: Any problem is likely to be with the connections, not the Add-A-Zone. In case it is not obvious, would recommend waterproof connectors and get them out of the water if at all possible. Sometimes it is as simple as putting a tie wrap loosely around the bundle of connectors and pulling them towards the top of the valve box. Another less attractive option is to dig deeper than the valve box and fill the extra space with gravel to enable quicker drainage..
which one is more reliable? Add-a-zone, or Doubler?

Reza R on Sep 13, 2014
RCO Single-Wire Dual-Zone Control | ADD-A-ZONE
RCO Single-Wire Dual-Zone Control | ADD-A-ZONE
Transitional Systems Most Dual-Valve Operator | DOUBLER
Transitional Systems Most Dual-Valve Operator | DOUBLER
BEST ANSWER: Doubler is mechanical, like a click pen. It will work with finicky controllers.
Add-A-Zone is solid state and will last for years. However, some electronic controllers will not operate properly with it. More info: Search - Triac Quadrant
How far away can you locate the new valve from the original valve in the field?
Colby G on Aug 12, 2019
BEST ANSWER: My guess is....as far as your wire will reach. When it comes off the add-a-zone control unit at the original valve, it has 2 wires that you run out to your new valve. Other than wire resistance, i don't think there is a limit.
is there an add-a-zone that will handle more than 2 valves, such as 3 or 4?
Marty F on Jan 17, 2018
BEST ANSWER: There is no such thing....

Add a zone uses a single control wire to control only (2) separate valves .
You can use multiple add a zones in a single controller but requires additional available stations at the controller and additional control wires in the field.
simple question: What do I get when I purchase a R Co Add-A-Zone Single-Wire Dual-Zone Control? Your picture shows just the box controller? There has to be more to it? Does it come with a unit that goes into the controller location? There has to be more than just the main box?
Richard H on Mar 18, 2016
BEST ANSWER: It comes with a small wire harness that wires to the controller and has a transmitter the size of a marble on it. Then the bigger box unit gets wired to the valves. It comes with both. Only thing you'll need is some wire nuts and a maybe a little wire depending on your application.
Can multiple add a zones be used oh a system with sufficient capacity on the controller?
A shopper on May 18, 2015
BEST ANSWER: The Add-A-Zone itself, uses very little power. You can use as many as you have zones for. Each Add-A-Zone set (smaller device at controller, larger device at valves) will use two controller stations and one field wire (plus common) to individually supply two valves or valve groups. A valve group may include up to the maximum available controller supply, usually two or three 3watt solenoids (this must be calculated using solenoid label values and controller ratings.
Will this device work with a weathermatic timer to add a master valve to an existing valve near by?
ams-ca on Jan 16, 2015
BEST ANSWER: The add a zone works by switching back and forth between two zone valves. For instance, If you have it connected to zones 3 and 4, current will first flow to the zone 3 solenoid. Once zone 3 shuts off, the add-a-zone will switch the current to be routed to the zone 4 solenoid. Once zone 4 shuts off the add-a-zone is in position to supply current to zone 3. It will not supply current to two valves at the same time. So if you want a master valve to be supplied with current continuously when the system is calling for water, in theory, you could use two add-a-zones wired in parallel circuit. The wiring is complicated, but I just sketched out a schematic and it looks like it would work. A good electrician would be able to figure out this circuit.
confused about the wiring in the controller. The yellows go ta a used terminal and an unused terminal, so where does the red wire go?
A shopper on Mar 22, 2012
BEST ANSWER: To recollection, the colors that were indicated in the instruction manual did not match the item that I was sent. Other than that the schematic was correct. Regardless, make sure that you are not confusing which part stays with the contrroller and which part that is burried in the field. The small part stays indoors, the "box" is in the field.The small adapater has two wires that go to two zones terminals, the third goes to the only working wire that is goes to to your lawn. The box takes the other end of "this" wire and along with the the common spits to the two valves. The common is shared with both valves. The item works flawlessly as if you really do have separate sets of wires. Too bad the price of the product jumped quite a bit in 3 months.
If the add-a-zone doesn't work quite right with the timer, where can I get the TX Power & Signal Booster referred to on the back of the package?
Tim B on Jul 21, 2015
BEST ANSWER: I can't really help with regard to the booster that you referenced - I had no problem with the Add A Zone installation other than the color coding of wires has changed since the production of their video. The packaging was representative of what I received so it wasn't a big deal. I'm using it with a Rachio controller and it is working well.
Is there a maximum distance the Add-A-Zone can be installed from the valve you are tying it in to? Basically does it have to be installed next to the valve I want to tie it to or can I spice 100' of wire between the add-a-zone and the "partner" valve?
Dennis E on Jun 16, 2013
BEST ANSWER: I have placed an Add-a-Zone at one valve box and run more than 100 ft. of wire to the other valve, so Yes.
Can I use add a zone on a two wire system with decoders?
Alonzo S on Aug 12, 2019
BEST ANSWER: I don't believe you can. Or if you did, could you rely on it to function week/months out? I've installed countless Add-A-Zone's but never on a a 2 wire sys. Their customer service is as good as that part you're looking at there. It's the best one I've found, period. If you contact R Co. customer service they'll tell you for certain if if can or not
What does each colored light represent?
A shopper on Sep 27, 2017
BEST ANSWER: This has colored wires not lights. The device has two components. The component at the control box uses 1 ground and two zone connections and maps these to two output wires that go to a single valve. At the valve box the second device has two input wires that attache to the two wires coming from the control panel box. On the other side of the control device are 4 wires. One pair for each of two valves. When wired correctly and the lower control box zone is on the source device sends a forward signal to activate outside valve #1. When the controller switches to the higher zone, the flow is reversed and now the other outside valve is activated. In short two outside valves are controlled using 1 single pair of control valve wires. Hope that helps.
How do I connect 3 zones to add a zone? Do I.need 2 add a zones? I already have a doubler but need to add another zone because of broken wire.
Jimmie O on Jul 14, 2017
BEST ANSWER: One "add a zone" per zone you are adding. One wire needed per add a zone (wire used by another valve). Works just like the Doubler.
Which version of the Add-A-Zone product does SprinklerWarehouse carry at the present time? Would like to ensure that I receive the later models rather than that pictured on the website due to issues with these older models.
Kevin O on Mar 5, 2016
BEST ANSWER: I purchased Add-A-Zone+ (Model: RCO860009) early last spring. I added a new sprinkler section but didn't have a line for it. This product answered my problem perfectly. It was a very straight forward installation and worked perfectly last summer. I am confident it will continue performing just as well this year and beyond. This is a great solution for a similar problem and I can enthusiastically recommend it.
Installation instructions for add a zone ?
A shopper on Sep 22, 2018
BEST ANSWER: They are on the packaging. Large piece goes outside in valve box. Small piece goes in controller.
I bought the ADD-A-ZONE and it worked when I manually turn the stations on from the controller but the two zones I have connect to the ADD-A-ZONE don't show up when I try and program the controller. Any ideas on how to fix this?
Mike L on Sep 10, 2017
BEST ANSWER: Mine show up fine when programming it, I have not had any problems with it.
I have even used one in order to add a master valve. and it works great as well.
A shopper on Aug 2, 2012
BEST ANSWER: I have only used this device twice so I cannot remember the exact steps. I do remember it was pretty straightforward. Just followed the directions that came with it. If you are knowledgable on basic irrigation wiring you should have no problem. Nothing tricky.
What are the dimensions?
A shopper on Aug 2, 2019
I have a Rain Dial 12 controller. Zone #1 quit working, and by checking it, discovered it was a break in that field wire. Solution was using the Add-A-Zone and the field wire for zone #2. I wired it up per instructions but now, when I manually run these stations, Zone #3 comes on when I activate zone 1 or 2 or 3 at the controller. Zones 1 & 2 are located in a different valve box then 3. The remaining zones 4 through 10 work normally. Any ideas?
Mark B on May 29, 2019
any warranty on add-a-zone?
bland y on Aug 28, 2018
will it fit on a superior controller ?
A shopper on Aug 23, 2017