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Accu-Rain Watering System Review







The AccuRain company closed and to my knowledge this product is no longer available. I am leaving this post as an interesting historical piece since this was an interesting and unique sprinkler system.



The Accu-Rain Watering System is a radically different sprinkler system that consists of motorized sprinkler heads called "robots" located at strategic points around the yard. A single robot can water anything within a 30 foot radius around the robot. The area is watered by a single stream of water from the robot, which the robot directs to various points around the yard. A computer controller tells the robot where to direct the stream. The robot controls the stream through the use of a nozzle mounted on a motor-rotated turret and a valve that varies the water pressure to control how far the stream goes from the robot. At low pressure the stream just barely squirts and lands right at the base of the robot, at high pressure the stream shoots 30 or more feet away. In order to water an area the robot "paints" the area with water by moving the stream back and forth over the area in a pattern from one side to the other. The areas to be watered do not need to be rectangular, they can be almost any shape. I've successfully watered a number of odd shaped areas using the robot, although it does have some limitations.

The areas of the yard to be watered by a single robot can be divided into separate "zones". For example, one zone might be a lawn, another a group of desert cactus, another zone might be a grouping of thirsty tropical plants. Each robot can water several zones and each zone can be watered for different lengths of time, and can be watered on different days. Each zone is essentially independent of the others. For my test system I installed one robot and set up several zones for it to water. One zone is tropical plants around my spa that get watered 3 days a week, another is native plants that get watered once a week, another is some nursery plants in containers that get watered every other day, and the last one is my spa cover (I set up the robot to hose it down once a week to remove the dust!) Unfortunately I have not yet found a way to make it detect my neighbor's cats and squirt them when they use my landscape as a litter box. (Don't misunderstand me, I like cats, I just don't like cleaning up after other people's cats.)

Accu-Rain Watering System
The Accu-Rain Watering System robot operating.

The installation of the Accu-Rain Watering System is fairly straight forward, but is significantly different from installing a standard irrigation system. The robots are mounted 4 around feet above ground level. The robot needs to be attached to a stable surface, such as a post, fence or wall. (My test unit is attached to a fence, and is 6 feet high.) A pipe goes from the water source to the robot. A set of wires is installed from the robot to the location where the remote control unit will be installed, which needs to be near a standard 120 VAC power outlet. (For my test unit I installed the controller on the wall in my garage.) The wires provide power for the controller and the robot, they also allow the controller and robot to communicate with each other.

Accu-rain controller.
Controller attached to junction box on wall.

To initially program the shape of the zones, the portable controller is taken out to the robot location, where it plugs into the robot. With the water on, a system of directional buttons, similar to the curser (arrow) keys on your computer keyboard, are used to move the stream. You move the stream to a series of points along the perimeter of the watering zone. This works much like a video game. These points define the edges of the area to be watered, somewhat like a dot-to-dot drawing. After the area to be watered is defined, the desired watering information is entered into the controller, ie; what days to water and how much water (in inches of water depth) to apply on those days. Once the robot is programmed, the remote is disconnected from it and is hung on the wall in a permanent indoor location. A set of control wires connects each robot to the controller, and also connects the controller to the power supply. From this point on the system is automatic, the remote controller tells the robot to water on the selected days and the robot proceeds to direct a stream of water back and forth across each of the zones. You can now adjust the watering schedule using the remote controller, without going out and connecting it to each of the robots.


Programming the robot.
Programming the robot using the controller .


Rain switch. The Accu-Rain Watering System can have a 3rd party rain-switch attached to it. A rain-switch shuts off the irrigation when it rains.

Smart Controller qualifications. The Accu-Rain II Watering System does NOT qualify as a Smart Controller operated system. (Smart Controllers automatically adjust the watering times for seasonal changes in water demand.) Thus it may not be used in the growing number of cities that require all new irrigation systems to utilize Smart Controllers. I believe the Accu-Rain Watering System can be modified to use a moisture sensor (thus making it "Smart") using the rain sensor circuit, however due to the program operation logic it would not be a very efficient use of the moisture sensor. However I do believe that in most cases it would meet the minimum "Smart Controller"qualifications when rigged with a moisture sensor. To add a moisture sensor the system would need to be set up so that the highest water use zone operated last (such as a grass area in the sun). The 3rd party moisture sensor needs to be the type that breaks a circuit when sufficient soil moisture is detected. Then the moisture sensor would be installed in this last zone and wired to the rain switch terminals in the Accu-Rain System junction box. Wired in this manner the moisture sensor would cancel a complete day's irrigation if the soil in the last zone was wet, however it would not shorten irrigation times for that day. So it would only cancel a full day's irrigation. While it would save water, it would not be nearly as efficient as a true watering time reduction system. Contact Accu-Rain for more specific instructions.

The Accu-Rain website has more detailed information on the operation of the system, including videos. A video, where you can see the robot working, is really helpful in understanding how this works.

An inside look at the Accu-Rain robot.
An inside look at the Accu-Rain robot.

My Experience:

Update, August 2009. My test unit stopped working. According to their phone answering machine, the AccuRain company is now closed and out of business.

Update: The following comments are based on my test unit, which was the original Accu-Rain model. A new Accu-Rain II-M model is now available. The Accu-Rain II-M robot looks different from the model I tested, it is shaped like a box, rather than a globe like my unit in the photos above. Accu-Rain claims that many of the issues I raise below have now been corrected with the new Accu-Rain II-M model. Since they now have a new model, in the interest of fairness, I have included Accu-Rain's response to each of my comments at the bottom of this page.

Here are my thoughts from installing and testing the original Accu-Rain System, with some updated comments added later after a full season of operation:

1. This is a no-wind irrigation system. When the wind blows even slightly it does not work well at all. Any amount of wind makes the water stream go to the wrong place. I live in a very windy location, but I have no problems as long as I run it during the calm morning hours before the ocean breeze comes blowing in.

2. The wire connections are difficult to make and require care as to not break components inside the robot and junction box. It is also easy to short the wires and tools against the other circuitry in the units.

3. My test robot leaked slightly when turned off. It appears to be due to the internal valve not fully closing, likely something is stuck in it. Update: it stopped leaking after a couple of weeks. Whatever was jamming the valve apparently worked it's way out.

4. The sprinkler head must be mounted 4 feet above ground. It needs to be attached to a fence post or the side of a building or something else to stabilize it. This could make it a pretty ugly intrusion in some landscapes. I mounted mine on my screen fence around my spa.

5. The unit is designed to require between 45 - 80 PSI. My test unit operated at less pressure but the radius suffered:

30 PSI = 28' radius
40 PSI = 32' radius
50+ PSI = 35' radius

6. It has a maximum pressure rating of 75 PSI per the label on the robot (the original manual says "80 PSI") so you will need a pressure regulator if your static water pressure is higher. If you need a regulator, I strongly recommend a brass, adjustable pressure regulator be used. Do not use the plastic, pre-set regulators, they will not work with this unit and it will break your robot. Most cheap pressure regulators/ pressure reducers allow a short burst of high pressure through them when the water is first turned on. This short pressure burst will damage the robot.

7. I strongly recommend a 150 mesh screen filter be installed before the unit. It appears to be very sensitive to any amount of contaminants in the water.

8. It took me much longer to install it than I thought it would. Just a warning, allow all weekend to install a couple of robots and get them fine-tuned. Like all projects you'll likely need to make an emergency trip to the hardware store for something you never dreamed you would need!

9. Most yards will need multiple robot heads. Be sure to layout your design before you purchase it. I recommend you assume no more than a 28' radius for each robot based on my tests.

10. I experienced some keypad sensitivity problems with the control unit. It tended to skip ahead, probably due to reading a single key-click as a double-click. Update: this problem persists and has become very annoying!

11. The instruction manual appears to be several different manuals combined together. It has good and complete information, but it isn't laid out in a logical order. I understand a new manual is being written. Update: I have the new manual and it is a huge improvement!

12. The wire colors used for the controller and robot for some reason don't follow the industry standards for irrigation systems. This is only a problem if the installer is an experienced irrigation person and doesn't read the instructions carefully.

13. The Accu-Rain system utilizes a junction box between the wire and the controller that is very, very poorly designed. It is way too small for the wire connections to be easily made. It attaches to the wall with double stick tape and has no screw holes to allow for a more permanent attachment. Really cheap. While my test model had a different style box than the one in the manual, the new one was no better than the old one. It would be very easy to accidentally short the robot control wire against the power source in the box. It is critical to be careful when wiring the junction box. Be sure the power supply is disconnected. Update: see Accu-Rain's response below.

14. The robot over sprays the area to be irrigated at the start of each cycle. When it first comes on it shoots the maximum radius for just a second, but enough to get water onto walls or windows if they are less than 35' away from the robot. Make sure the first "dot" of the watering area you lay out is aimed in a direction where this overspray will not hit a window, building wall, or spray someone! Update: see Accu-Rain's response below.

15. The controller program sequence is linear, to make a change in any portion of the program you must walk through the entire sequence. The sequence is reasonably logical to follow, although I suspect it will help if the user is a bit of a "computer geek". I've seen worse, but I've seen better logic, too. Easier access to the "rain off" function and seasonal weather setting functions would be nice. A lot of people are going to have difficulty with the programming. Update: this has become even more annoying with time. It makes seasonal watering time adjustments a pain in the butt. A system of this caliber should really incorporate "Smart Controller" technology. It would not be very difficult to add a historical ET function that would allow for 12-month water scheduling.

16. In regards to actual operation, my test unit waters the 4 zones that I laid out for it without problems (as long as the wind isn't blowing.) I laid out one complicated boundary with lots of irregular curved edges and it waters thoroughly the areas within those boundaries, and only the areas within those boundaries. The basic operation and water application is good. As would be expected, any large object between the robot and the area to be watered blocks the water spray leaving a dry spot. For example, a tree trunk blocks watering of the area on the far side of the trunk from the robot. The water stream from the robot will not penetrate through even very thin foliage. There can't be anything taller than the robot height between the robot and the area to be watered or the watering stream will be blocked.

Splash & splatter. (Update) The water stream from the Accu-Rain robot causes some splash when it hits the ground. When I tested watering a patch of dirt along the edge of a sidewalk, it splashed a lot of dirt onto the sidewalk surface. I discovered this can be reduced to an acceptable level by installing a layer of medium size (not small, it gets moved by the water stream just like the dirt) bark, wood chips, or decorative rock. This splashing does bring up another issue, which is that this system is not good for growing grass from seed. The water stream splatters the seed and top-dressing around. If you must seed an area watered by the Accu-Rain system I suggest you use hydroseed, and that your hydroseed mix include a high level of mulch along with a tackifier. A tackifier is essentially glue that holds the seed in place.


Accu-Rain's Response:

Below is Accu-Rain's response to the items in my comments above. Items numbers below correspond to the numbers in my comments above.

1. Wind is a factor using our system. In most cases, the effects of the wind shift the zone boundaries. The majority of the zone will still be watered, however. As with most other irrigation techniques, we recommend watering early in the day to avoid wind and reduce evaporation.

2. This has been completely redesigned with the Accu-Rain II model. First, we switched from a 4-wire to a 2-wire system. Second, the terminations at the head and junction box are made with captivated screw down terminals. Third, the terminations at the head have been relocated to the periphery to aid access. Bottom line is that you can terminate a head very easily now compared to the previous version.

3. This is most likely caused by some bit of trash or debris in the main valve area. There is a simple procedure to clean the membrane thereby eliminating this problem. This often happens at start-up when people do not clear there line prior to installing the head.

My response: I flushed this system really good. If you've read my tutorials you know how I feel about the importance of flushing pipes. I think it was a small amount of manufacturing debris inside the unit. That's fairly common with valve manufacturing, I've seen a lot of it over the years with every brand of valve. No big deal, it stopped leaking on it's own before I got around to cleaning it.

4. There is a direct connection between 4 feet installation height and 30 feet throw distance. The heads can be mounted higher or lower than four feet, but the throw distance will be effected. The heads do need to be stabile for proper operation. Accu-Rain introduced a new custom bracket to help customer achieve this easily.

5. No comment here. This seems normal.

6. No comments here. We have updated the manual to reflect the operating range of 45-75 psi.

7. The new valve with the Accu-Rain II units should less sensitive to debris in the water supply. However, this is not a bad idea especially if you know the water supply is dirty.

8. A question for you. Which part of the project took longer than expected? Terminations?

My reply: Connecting the terminals was hard, especially with my less than great eyesight. But installation of the pipe and wires to service the robot also took longer than I expected. Digging trenches, installing bracing to keep the robot from wobbling when operating, etc.. I also had to install a pressure reducing valve due to very high water pressure, which I hadn't planned for. Like many projects, it simply took longer than expected.

9. Sound advice.

10. This issue was a problem from time to time. We have not had the same issue yet with the new system.

11. New manuals are available online in the “reference” section.

12. The Accu-Rain II system uses only 2 wires. We recommend the standard sprinkler wire 18 AWG, 2 Conductor (Red, White), under a common PVC jacket, rated for direct burial.

13. We have replaced and redesigned the Junction Box completely... It has a screw hole for attachment to the wall, etc. You can also terminate 2 cable and a rain sensor directly to the box.

14. With the Accu-Rain II unit it is the opposite. The valve slowly opens to the programmed distance and proceeds to water. When I say slow, I mean a .25-.5 seconds.

15. There are a few minor differences with the programming, but it is very similar to the previous version.

16. OK.



(Conclusion updated on April, 2007, after a year of testing.)
I think this is a great system if you understand it's limitations. I'm anxious to see what it looks like after a few more upgrades, I think it has the potential to really shake up the residential irrigation industry! For now, I still think this system is best only for those who like to tinkerer with gadgets, and like the idea of having the coolest sprinkler system in the neighborhood!

The Accu-Rain Watering System should not be used unless you have several hours of wind-free (no wind at all!) time daily in which to water. A slight breeze completely destroys the coverage uniformity on my test system. If you have problems setting a digital clock or a VCR you should probably avoid this system. It programs in a very similar manner to a VCR with on-screen prompts. I haven't tested the new model so I can't say how much better it is, but as you see in the response by Accu-Rain, they feel they have made significant improvements that negate many of my comments in the list above. Even if you are comfortable with programming stuff, adjusting the controller is a pain due to the linear input, especially making seasonal adjustments to the watering times. I have noticed over the past year that my controller unit sometimes seems to go a bit haywire, displaying some error messages. However it does reboot itself after a few seconds and returns to normal. I suspect this problem has been caused by me pushing the buttons too fast or accidentally hitting two buttons at once. Another warning, if the power goes off or you unplug the controller from the junction box (like taking it out to reprogram a robot) you will have to reset the current time. The rest of the program information is preserved. Too bad they don't have a back-up battery in the controller to maintain the time setting, back-up batteries are a feature that almost every other irrigation controller on the market has.

If you plan to install the Accu-Rain Watering System yourself you should be aware that it requires an intermediate level of plumbing/electrical knowledge and skills to install. Any serious "handy-person" type will not find anything here beyond their abilities. Plan to spend at least $200.00 plus an extra $100.00 per robot for additional parts needed for the installation such as pipe, wire, pressure regulators, filters, etc. Your actual cost will vary, of course, based on your yard size and shape. If you have low water pressure (under 55 PSI) be sure to use a reasonably large pipe to supply water to the robots. I would suggest the pipe be no smaller than 3/4 inch. At a minimum, it will take you a full 2-days to complete the installation. If you need a lot of trenches for pipes and wires, the time needed can expand quickly. I cleared the memory out of my robots and controller as a test to see how long it would take me just to re-program the system now that I am familiar with it. It still took me 4 hours to program one robot, including time for a test run of each zone.

We had an unexpectedly freeze this past winter here in Southern California. A large number of the more tropical landscape plants were killed, and a lot of irrigation equipment that wasn't insulated or drained froze and broke. Since it doesn't normally freeze here I did not have a drain valve installed on my robot water supply. I should have simply cut the water supply pipe under the robot to drain the water, but I was lazy-- and it was cold outside! (I'm a native Southern Californian, I put on a coat when it drops a couple degrees below room temperature!) So I went out to the controller in my garage and reset the water amount for all the zones to 2 inches of water, then set them all to run that day, and finally I set the start time to 11 PM. The robot kicked on at 11 PM and ran all night while the temperature dropped into the 20's (F). I am pleased to report that the robot was not damaged. (The running water doesn't freeze as easily, similar to leaving a faucet dripping to protect it from freezing.) It left pretty icicles all over my plants! The robot does have small water passages and should not be allowed to freeze. My experience indicates the robots will survive a unexpected light freeze without being drained. However, if you live in a cold climate be sure to install drain valves, and fully drain the robots before the first hard freeze.

My Wish List for future versions of the Accu-Rain:

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