Among the sprinklers available on the market, the Rain Bird Maxi Paw has a unique selling point: it’s the only pop-up impact sprinkler I know of. Impact sprinklers have largely disappeared from private gardens in recent decades with the rise of gear-driven sprinklers. However, they can still be a viable alternative in challenging water conditions. In this article, I’ve taken a closer look at the Rain Bird Maxi Paw.

What are impact sprinklers?

Impact sprinklers are the sprinklers many people remember from their childhood. Impressive devices with a powerful spray, usually mounted on a tripod, they made quite a bit of noise when operating and sprayed a lot of water in the immediate vicinity. This last point made them particularly popular with children, as they could stand next to them in the summer and enjoy a pleasant cooling spray.

This water distribution is achieved by the jet separator, a usually rod-shaped barrier mounted in front of the nozzle. The water shooting through the nozzle hits the jet separator and deflects it to the side. A spring then returns the jet separator to its original position, where it is struck by the jet again. Each deflection causes the sprinkler to rotate a small amount. The impact of the jet on the jet separator creates the characteristic tapping sound of this type of sprinkler and distributes the water in the immediate vicinity.

When is an impact sprinkler necessary?

Impulse sprinklers are still commonplace in agriculture. However, they have become rare in private gardens. Gear-driven sprinklers, sprayers, and rotators have gradually replaced impact sprinklers. These offer several advantages over impact sprinklers: They are significantly quieter, provide more even watering, and are easier to adjust.

The first point is particularly important, as private gardens are usually built right up against the neighbor’s fence, and the impact noise of a sprinkler can be quite loud and perceived as disruptive. Modern gear-driven sprinklers aren’t completely silent either, but they produce a quieter and much more consistent sound.

Therefore, aside from nostalgia, there’s currently no real reason to opt for an impact sprinkler. With one exception: If you only have slightly dirty water available for irrigation, containing sand or sediment, then an impact sprinkler can be a welcome solution!

Gear-driven sprinklers struggle with such conditions, as their gears can become clogged and quickly stop functioning correctly. This is usually solved by using a filter to ensure the water is clean before entering the pipeline. However, with very fine sand, algae, or organic contaminants, this can be difficult and expensive, and may also require a relatively high water pressure.

This explains why the Rain Bird Maxi Paw continues to hold its own in the Rain Bird product range: as a virtually indestructible, robust workhorse, its exposed mechanics and straightforward, simple design make it relatively insensitive to harsh conditions, and it performs reliably even in challenging environments. And I only recommend using it for this specific application; otherwise, a modern gear-driven or rotary sprinkler is a better choice!

Rain Bird Maxi Paw Under the Microscope

What immediately stands out about this sprinkler is its comparatively enormous size. This applies not only to the cap, which has a much larger diameter than other sprinklers, but also to the sprinkler itself.

The relatively large height might make connecting it to the pipeline a bit more difficult. However, the Maxi Paw addresses this by providing not only the standard 3/4-inch connection at the bottom, but also an optional 1/2-inch connection on the side. To use the latter, simply unscrew the plug from the side connection, thus sealing the bottom connection. Even if it doesn’t look like it at first glance: The plug is large enough for this, as the 3/4 inch connection at the base of the sprinkler tapers inwards.

Size comparison of Rain Bird Maxi Paw with Rain Bird 3500 gear-driven sprinkler

Variants

The full name of the sprinkler is Rain Bird Maxi Paw 2045. The 20 indicates the minimum throw distance of 20 feet (6 meters), and the 45 indicates the maximum throw distance of 45 feet (13.7 meters). One or more letters follow to distinguish the four variants:

• 2045A – The standard model
• 2045A-NP – Same as above, but with a purple cap instead of black, indicating the use of grey water
• 2045A-SAM – With an additional Seal-A-Matic check valve, which prevents puddles from forming when used on uneven terrain
• 2045A-SAM-NP – With a purple grey water cap and Seal-A-Matic check valve

The “Maxi” in Maxi Paw is there because there was previously a smaller model called the Mini Paw. This model has since been discontinued.

The sprinkler is available with a total of 7 different nozzles. The five nozzles 06, 07, 08, 10, and 12 allow for smaller or larger water flow rates and throw distances, respectively. The two nozzles 07LA and 10LA are low-angle nozzles that distribute the water at a shallower angle than the other nozzles. This can be advantageous in areas with strong winds.

Key data Rain Bird Maxi Paw

Name

Rain Bird Maxi Paw

Maximum possible radius:

65 ft. (13.7 m)

Minimum possible radius

30 ft. (6 m)

Adjustable arc

40° to 360°

Water pressure range

25 to 60 psi (1.7 to 4.1 bar)

Water consumption

1.5 to 8.4 gpm (5.6 to 31.8 L)

Precipitation rate

0.28 to 1.21 in/hr (7 to 31 mm/h)

MPR nozzles

Pressure regulation

Inlet size

3/4 inch male thread or alternatively 1/2 inch female thread

Price

$37.99

Name

Rain Bird Maxi Paw

Maximum possible radius:

65 ft. (13.7 m)

Minimum possible radius

30 ft. (6 m)

Adjustable arc

40° to 360°

Water pressure range

25 to 60 psi (1.7 to 4.1 bar)

Water consumption

1.5 to 8.4 gpm (5.6 to 31.8 L)

Precipitation rate

0.28 to 1.21 in/hr (7 to 31 mm/h)

MPR nozzles

Pressure regulation

Inlet size

3/4 inch male thread or alternatively 1/2 inch female thread

Price

$37.99

Adjustment

Adjusting the sprinkler isn’t rocket science. However, compared to modern sprinklers that make it very easy, it’s still a bit more challenging. You can adjust the irrigation sector (either a full circle or a setting from 20 to 340 degrees) and the throw distance using the adjustment screw (according to the manufacturer, a reduction of up to 25% is possible). The nozzles can also be changed.

A special adjustment tool is sold for the Maxi Paw sprinkler, which helps you pull out the riser and lock it in place. This is convenient and certainly not a bad idea if you have many sprinklers to adjust, but the adjustment can also be done by hand or with simple tools.

To pull out the riser, you need a very narrow tool, such as a very flat screwdriver or a flat spatula, to reach into the gap between the riser and the body and pry and pull it out. Instead of using the special adjustment tool to secure it, you can simply hold it in place with your own muscle power and make the necessary adjustments.

Moving the adjustment loops to set the irrigation sector and turning the deflector screw to reduce the spray distance requires no tools; this is done by hand. Changing nozzles is also easy: simply twist them 90 degrees, pull them out, and reinsert them in the same way.

Alternatively, the settings can be adjusted during actual operation, once the sprinkler is supplied with water and extends automatically. This saves you from having to hold the riser, but you shouldn’t mind getting wet, as it’s quite easy to do so.

Personal Impression

What immediately stands out, especially if you’re used to gear-driven or rotary sprinklers, is the forceful spray pattern. It feels significantly less elegant and refined than what you’re used to, but in my opinion, this isn’t a drawback for the intended application, as it explains why the Maxi Paw is much less affected by dirty water. The water is channeled through so directly and efficiently that no dirt can remain in the sprinkler.

In my test, the sprinkler function worked flawlessly. I also found the settings straightforward, and you don’t really need the additional adjustment tool. Simply use the metal adjustment loops to define the area to be irrigated, and you’re good to go. You only need to adjust the limit screw if you need to reduce the spray distance. I also tried changing the nozzle, which is equally simple. Just turn the nozzle 90 degrees and remove it. Then place the new one on top and turn it back 90 degrees to lock it in place.

With the available nozzle set, a matched precipitation rate across multiple sprinklers (MPR) is also possible. A pressure-regulating body is not offered for the Maxi Paw.

The noise level is significantly higher than with gear-driven or rotary sprinklers; it sounds a bit like the rattle of a machine gun. If you or your neighbors are sensitive to noise, an impact sprinkler is not ideal. To give you an idea, I’ve included a short video below showing the sprinkler operating for a few seconds and the noise it produces.

Video of the Bird Maxi Paw in action

In my experience, the Maxi Paw sprinkler irrigates more intensively in its immediate vicinity than gear-driven and rotary sprinklers, which only irrigate very weakly in this area. This would be a factor if the Maxi Paw were used as a standalone unit. In practice, however, impact sprinklers, like gear-driven and rotary sprinklers, should also be used in conjunction with other sprinklers in a square pattern or triangular pattern. This ensures that any uneven watering of one sprinkler is compensated for by the neighboring sprinklers.

In conclusion: If you have a choice, you don’t need to opt for the Maxi Paw, as there are now more modern and better sprinklers on the market, and it does have certain drawbacks. However, for heavy-duty work in difficult water conditions where other sprinklers fail, it is a well-functioning alternative! The sprinkler reliably does what it’s supposed to and, while not quite as easy to use as some other sprinklers, is still quite simple to operate. One drawback is the relatively large area it occupies in the lawn and the somewhat higher operating noise.

Where to buy

The sprinkler is available for around 20 dollar in garden centers, specialist shops and on Amazon (link to product).

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Even if you’ve planned everything perfectly, redesigning your garden may require adapting an existing irrigation sector and relocating sprinklers to other locations or deactivating them. The best way to proceed depends primarily on whether the change is permanent or temporary. There are basically two options:

• Remove the sprinkler completely from the pipeline
• Leave the sprinkler in the pipeline, but ensure it no longer releases water

If the deactivation has a limited expiration date and the sprinkler is to be used as usual afterward, the second option is recommended, for example, if you set up a sandbox for your children in the garden for a few years, but already know that it will disappear again afterward. Or, for example, if a renovation involves temporarily dedicating a section of the garden to storage and not watering it. However, if the renovation is permanent and renders the sprinkler obsolete, it should be removed completely.

Turning off sprinklers

On the one hand, there are sprinklers and sprayers that have a shut-off function. This includes all Hunter and Rain Bird spray nozzles, whose water flow can be reduced to zero using the adjustment screw. This is also possible with the Gardena SD30 and SD80 pop-up sprayers. Hunter and Rain Bird also offer this option for their state-of-the-art Hunter I-20 and Rain Bird 5000 plus gear-driven sprinklers. Shutting off ensures that no water is released, but the sprinklers still rise. All older Hunter and Rain Bird gear-driven sprinklers and all other Gardena sprinklers do not have an integrated shut-off option.

With the Hunter MP Rotator, there are two options: For Pro-Spray, PRS30, and PRS40 bodies, there are special Hunter sealing caps that can be screwed on instead of the standard cap to seal the bodies at the top. Alternatively, you can screw a Hunter blind nozzle onto all bodies with a 5/8-inch external thread riser instead of standard nozzles. In this case, the nozzle still rises, unlike the previous version, but no longer releases water. These practical shut-off caps and blind nozzles are rarely available in stores. Without knowing exactly what you’re looking for, it’s difficult to find these products, so here are two direct Amazon links*:

• Amazon offer: Hunter Pro-Spray Cap
• Amazon offer: Hunter Blind Nozzle

Removing the sprinkler and closing the connector

If the sprinkler doesn’t offer any of the options listed above, or if you want to remove it permanently anyway, the easiest way is to remove it and seal the connector attached to the pipeline with a cap. To do this, proceed as follows:

The theoretically possible minimum is to unscrew the sprinkler from the top of the connector by twisting it and then pull it out of the ground. The connector thread is then exposed, and if you have very narrow hands and a lot of fingertip strength, you could theoretically unscrew the cap right away.

In practice, however, this doesn’t really work. On the one hand, there’s a very high risk of accidentally getting soil into the pipeline, and on the other hand, the narrow access makes it almost impossible to exert enough force to properly unscrew the cap, and you also don’t have the necessary space to wrap the thread with Teflon tape beforehand to seal it!

Therefore, you’ll have to invest a few extra minutes and dig a few centimeters around the sprinkler. This is done before unscrewing the sprinkler from the thread to prevent soil from falling into the pipeline during excavation work. Only after the connection point has been thoroughly exposed and cleaned should the sprinkler be unscrewed. If it was mounted on a swing joint, both the sprinkler and the swing joint are removed. Now carefully wrap Teflon tape around the thread of the connector and screw on the cap. It is sufficient to tighten it by hand; no tools are required. Then, pressurize the irrigation system and check that the cap is tight. If everything is correct, the hole can be filled again.

Step-by-step process in pictures:

Special case: When the sprinkler is the last one in the line

The procedure described should be omitted if the sprinkler to be removed is the last one in the line and the pipeline is blown out with compressed air before winter. In this case, this would create a dead end in the irrigation system, where the water would stagnate during the winter and could cause frost damage. Therefore, in such a case, the plug is installed at the sprinkler that was previously passed through in the line. This means the next one in the direction of the water source from the sprinkler to be removed. Immediately after this sprinkler, the pipeline pipe is cut off and an end cap or connector end piece is installed. The removed sprinkler then no longer needs to be plugged, as the upstream section of pipe no longer serves any function. Here, too, a leak test must be performed before filling the pipe.

Caps/Blank Plugs

Caps and blank plugs are available in plastic or metal and are available from irrigation companies such as Rain Bird or Gardena and a variety of other companies. Most sprinklers require caps with a 1/2-inch internal thread; larger sprinklers also require caps with a 3/4-inch internal thread. Some caps include an internal sealing ring, eliminating the need for additional sealing with Teflon tape.

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In this article, I’ll show you how to adjust the sector to be watered and the throw distance for Gardena sprinklers from the T-series, SD-series, MD-series, and OS-140 rectangular sprinkler.

These series currently include the following models:

• T Series: T-100, T-200, T-380
• SD Series: SD30, SD80
• MD Series: MD40, MD80, MD180
• OS-140: Available in only one model version

I also provide information on the best settings to make on the sprinkler before use, to avoid any wet surprises when adjusting the settings, for example, to prevent accidentally watering sensitive areas in the garden or giving your neighbor a cold shower. This allows even inexperienced users to adjust the settings without hassle or stress.

Gardena T-Sprinkler

The settings for the three T-sprinklers differ for the T-100 and the T-200/T-380 models.

Gardena T-100

Preparation (before turning on the water supply)

The T-100 sprinklers are factory-set for 360-degree full-circle irrigation. This can be recognized by the black adjustment arrow on the orange rotating sleeve pointing to the full-circle symbol below. Turning the orange sleeve counterclockwise reduces the area of the circle to be watered. To set the maximum possible reduction, turn the sleeve to the white line. The area to be watered is now only 70 degrees, i.e., smaller than a quarter of a circle.

By turning the gray piston, the entire sprinkler can be rotated; the sprinkler makes a rattling noise. If you turn it so far that the semicircle symbol points toward you, the sprinkler will spray away from you.

Activate the water supply

Now turn on the water supply; the spray pattern should now look something like this.

Adjust the sector to be watered

The left starting point of the sprinkler, i.e., the point up to which the sprinkler waters on the left side, is determined by grasping the entire sprinkler by the gray piston and twisting it, as described above.

If the left starting point is correct, you can adjust how far to the right the watering should extend by turning the orange sleeve clockwise, thus determining the size of the circular section to be watered. The further you turn clockwise, the larger the circular section is. If you turn it to the maximum possible point, the sprinkler will water a full circle.

Note: Turning the gray cap at the very top of the nozzle has no effect on the irrigated sector. Even if the cap is turned, the previously set area will continue to be watered.

Adjusting the Throw

By turning the orange screw located in the riser, you can reduce the water flow and thus shorten the sprinkler’s throw. It is best to use a screwdriver for this.

Gardena T-200/T-380

These two sprinklers are adjusted in the same way; I’ll demonstrate this using the T-200 as an example.

Preparation (before turning on the water supply)

Since this type of sprinkler delivers a very concentrated water supply, it is sufficient to prepare by turning the sprinkler nozzle away from you and toward the sector to be watered. This is done by turning the thin plate at the very top of the sprinkler head so that the small white arrow points in the direction of the sector. The sprinkler will begin watering at the position of the arrow.

Activating the water supply

Now you can activate the water supply without getting wet. If you have sensitive terrain around the sprinkler that should not be sprayed with water, it is better to read the next section beforehand so that you can quickly adjust the sector setting.

Setting the sector to be watered

The section of the circle that the sprinkler should water is defined by turning the two orange rings located in the riser. The left sector limit is set with the upper ring, and the right sector limit with the lower ring. The line marking on the ring defines the point to which the sprinkler rotates left or right.

Note: If the sprinkler head is accidentally rotated in everyday use, this will not affect the sector setting; the sprinkler automatically returns to the correct sector setting. Gardena calls this the “memory function.”

Nozzle Selection

There are four nozzles to choose from, each providing a different water flow. Nozzle 1 provides the smallest amount of water, and Nozzle 4 the largest.

The purpose of this nozzle selection is to enable coordination of the water flow rate (MPR) when operating the sprinkler simultaneously with other sprinklers that water different sector sizes in a single irrigation cycle. For example, if the first T-200 irrigates a full circle, the second only a semicircle, and the third only a quarter circle.

Since completing a full circle takes four times as long as completing a quarter circle, the irrigated area of the quarter-circle sprinkler would receive four times as much water in the same time as that of the full-circle sprinkler, resulting in completely uneven irrigation.

This can be compensated for by using different nozzle sizes. These should be used as follows:

• Nozzle No. 1 – Quarter Circle
• Nozzle No. 2 – Semicircle
• Nozzle No. 3 – Three-Quarter Circle
• Nozzle No. 4 – Full Circle

The nozzle is selected using a screwdriver by moving the arrow imprinted on the orange screw to the desired nozzle number.

Adjusting the throw distance

The throw distance can be reduced to 5 meters. This is done with the adjustment screw located above the nozzle. Turning it toward the minus symbol decreases the throw distance. Turning it back toward the plus symbol increases it again.

Gardena SD Sprinkler

The two SD models, SD30 and SD80, use the same adjustment method.

Gardena SD30/SD80

Preparation (before turning on the water supply)

By turning the turquoise adjusting ring on the black nozzle counterclockwise as far as possible, you reduce the area of the circle being watered to the smallest possible size of just 5 degrees. The adjusting ring can be turned about 1 1/2 turns until it stops.

Then, turn the sprinkler on the black riser so that the arrow on the adjusting ring points away from you in the direction you want to water.

Activate the water supply

When you activate the water supply, the sprinkler will spray in the direction of the arrow. Since the irrigation sector has been reduced to the minimum, only a single jet will initially emerge from the sprinkler.

Setting the sector to be watered

To do this, first turn the sprinkler on the riser as far to the left as you want the sprinkler to spray to the left. Then turn the turquoise adjusting ring clockwise as far as you want the sprinkler to spray to the right.

Adjusting the throw distance

The throw distance is adjusted by turning the screw in the adjusting ring. Turning it counterclockwise decreases the throw distance. With SD sprinklers, the throw distance can be adjusted significantly. If you turn it far enough to the left, you can even turn off the irrigation completely.

Warning: Do not loosen the control screw too much, otherwise the sprinkler head will come off!

Gardena MD Sprinklers

The MD sprinklers are currently the most modern Gardena sprinklers and, along with the OS-140, the only ones that can be adjusted completely without tools. The adjustment process is the same for all three available models MD40, MD80, and MD180.

Gardena MD40/MD80/MD180

Preparation (before turning on the water supply)

The area to be watered is reduced by turning the adjusting ring on the nozzle counterclockwise. After approximately 3/4 of a turn, the adjusting ring is in place and the circular section is reduced to a minimum of 80 degrees.

Now, turn the sprinkler head on the black riser until the small black arrow on it points away from you in the direction to be watered.

Activate the water supply

After watering has started, the spray pattern will look like this.

Adjust the sector to be watered

You can determine how far to the left the sprinkler should water by turning the riser to the left. You can determine the right point by turning the adjusting ring to the right. If you turn it as far to the right as possible, a full circle will be watered.

Adjust the throw

On MD sprinklers, this can be set without tools using the turquoise ring located in the riser. This can be turned up to a quarter turn. To the left, it decreases the throw, to the right, it increases it.

Note: Especially with the MD40, you’ll barely notice any difference at first glance; only a very slight adjustment of the throw distance is possible. The effect is more noticeable with the MD80 and MD180.

Gardena OS140

Preparation (before turning on the water supply)

With this sprinkler, this first step of preparing the sprinkler is particularly important, as it has a fairly large operating radius when fully turned on, posing a significant risk of inadvertently splashing water-sensitive items, yourself, or other people. Without first restraining the sprinkler, it is virtually impossible to adjust it without getting a shower.

To adjust the sprinkler, first unlock the two latches on the cover and remove it. The cover should only be replaced at the very end, as otherwise it would be difficult to reach the necessary adjustment points.

If you now pull the sprinkler out of the housing, you will see the orange adjustment mechanisms for the sector to be watered, the throw distance, and the throw width:

3 Adjustment mechanisms for the OS-140

The most important preliminary step is to reduce the water supply to the minimum using the orange dial. This allows the sprinkler to start with the shortest possible throw distance, allowing you to then work your way up to the appropriate throw distance. To do this, turn the adjustment wheel approximately 1/4 turn to the right until it stops.

I also recommend setting the throw width to the minimum initially. This is done for both sides using the orange sliders on the left and right.

Finally, grasp the sprinkler head and rotate it in the desired direction. The area to be watered is limited by turning the wheel on the side closest to you as far up as possible. Turn it so that the bar-shaped mark on the wheel is almost at the top.

Activate the water supply

After watering starts, the water will initially trickle weakly from the sprinkler, and due to the lack of water pressure, it probably won’t move yet.

Setting the irrigated sector, throw distance, and throw width

Now, slowly increase the water pressure on the orange wheel so that the sprinkler head begins to move. First, for the side facing away from you, turn the adjustment wheel and further increase the water pressure to determine the point to which the sprinkler head will swivel and how far in that direction the sprinkler will irrigate. At the same time, use the two slide controls to set the desired throw width.

It’s important to work your way up gradually until you find the best setting, as both the throw distance and the throw width respond to the set water pressure.

Then, in the same way, set the turning point for the side closest to you using the second adjustment wheel. During this step, you may need to step back a bit to avoid getting wet, as the sprinkler may now be watering overhead.

Once all settings are correct, you can finally replace the cover.

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The solution approach of strip sprinklers sounds compelling: instead of supplying a narrow strip of lawn with water using a large number of small circular sprinklers or sprayers, sprinklers are used that irrigate an almost rectangular pattern. This is why they are often referred to as rectangular sprinklers.

Such sprinklers are offered by Hunter, Rain Bird and other suppliers, although only Hunter with the MP-Rotator strip sprinklers and Rain Bird with the R-VAN strip sprinklers offer a rotating sprinkler type (rotating nozzle sprinkler), most of the other solutions offered are nozzle sprinklers that release the water in a comparatively gush-like manner and in large quantities. You notice this difference when comparing the rainfall rates.

The rectangular irrigation pattern is not achieved with one sprinkler alone in all solutions, but rather several sprinklers must be placed in a coordinated manner. With one sprinkler alone, many places, especially in the immediate vicinity of the sprinkler, would remain completely dry and even irrigation would not be possible.

Introducing the Hunter MP-Rotator side strip sprinkler

With this solution, three sprinklers are placed in a predetermined pattern to supply a strip of lawn. The width of the lawn strip is 60 inches. The Hunter MP Rotator side strip sprinkler is a circular sprinkler from the MP-Rotator family that has very low water consumption and also works according to the MPR principle, i.e. ensures that the lawn is watered as evenly as possible. The water is not released in a gush, but the sprinkler head moves during irrigation and divides the water into fine strips of water.

To supply a strip of lawn measuring 60 inches x 360 inches, you need the following 3 sprinklers:

• MP-LCS 515 -> Left Corner
• MP-RCS 515 -> Right Corner
• MP-SS 530-> Side Strip, to be placed in the middle of the strip

The body for this type of sprinkler must be purchased separately. You can get a cheap Pro-Spray body for around 3 USD, or even better, you can get a PRS-40 housing that is pressure-regulated to 40 psi for 10 to 12 USD. This automatically ensures that 40 psi of pressure (and no more) reaches the sprinkler, giving it exactly the ideal pressure recommended by the manufacturer. Of course, you have to make sure that enough pressure reaches the body yourself; the body can only reduce the pressure, not increase it.

In practice, the positioning of the 3 sprinklers looks something like this:

Irrigating a rectangular strip measuring 60 x 360 inches with Hunter MP-Rotator side strip sprinklers

The three sprinklers are all placed on the same side at the edge of the strip, the LCS on the left, the SS in the middle and the RCS on the right. From the sketched throwing area, you can see that you have to rain a little beyond the strip if you want to irrigate all the edge areas of the strip as well as possible. The sprinklers would be positioned about 180 inches apart and would supply water to a strip of about 60 x 360 inches.

If you instead have a lawn strip twice as wide, about 60 x 720 inches, you would need not 6 but only 5 sprinklers, three SS and one LCS and RCS each. The sprinklers are then placed, as before, at a distance of approximately 180 inches, as follows:

Watering a rectangular strip of 60 x 720 inches with Hunter MP-Rotator side strip sprinklers

Alternatively, you can also place two of the sprinklers on the opposite side:

Alternative positioning with two opposite sprinklers

And if you want to irrigate a short strip of 60 x 180 inches, then one LCS and one RCS sprinkler are sufficient:

Positioning for a strip of 60 x 180 inches

Water pressure

Hunter recommends a pressure of 40 psi on the sprinkler to operate this type of sprinkler ideally and specifies a rectangular area of ​​60 x 360 feet that is irrigated at 40 psi. The easiest way to achieve this perfect 40 psi is to use the appropriate body that is regulated to 40 psi pressure (Hunter Pro-Spray PRS-40). If a slightly smaller or larger strip is to be irrigated, the throw distance can be reduced or increased by increasing or decreasing the water pressure, or the throw distance can be reduced by up to 25% by adjusting the interference screw in the sprinkler.

Since the Hunter MP-Rotator side strip, like all MP-Rotator sprinklers, has a built-in MPR principle, the precipitation rate adjusts automatically. If an alternative PRS-30 body is used, which regulates the pressure to 30 psi, the irrigated rectangle would be approximately 47 x 340 feet. As always, it should be noted that these are laboratory values ​​that experience has shown are not quite achieved in practice. It is a good idea to always calculate about 10% less, i.e. place the sprinklers a little closer together.

Precipitation rate

The MP-Rotator side strip has a precipitation rate of approximately 0.58 inches/hour. This differs only slightly from the approximately 0.43 inches that the MP-Rotator usually has in the square pattern, so the MP-Rotator side strip sprinklers can also be operated together with the other MP-Rotator sprinklers in a zone.

This does not apply to the MP-Rotator MP800 series, as this has a precipitation rate that is almost twice as high at approximately 0.78 inches/hour. If you want to operate side strip sprinklers in a shared zone with MP800 sprinklers, Hunter recommends setting the sprinklers twice, i.e. once as described in the first and second positioning examples above and a second time opposite each other. This would result in a rainfall rate of approximately 1.14 inches per hour. Alternatively, you can also operate the side strip sprinklers in their own, independent sector.

Hunter MP-Rotator strip sprinkler in the test

I tried out the Hunter strip sprinklers in my test environment.

Hunter MP-Rotator RCS in action

The picture shows the sprinkler (RCS) to be placed in the right corner. The wet floor panels clearly show that the throw distance of 180 inches promised by the manufacturer is achieved quite well; one panel is 20 inches long and wide.

And here for comparison the MP-SS to be placed in the middle

To what extent are the throw distance and width accurate?

The test result matched the performance data promised by the manufacturer pretty well:

• The throw distance of 180 inches is pretty much achieved, only the last 20 inches were a bit tight, as only a few drops of water reached the area. In real operation, I would therefore be better off calculating with 20 inches less, so that the MPR principle is still adhered to at the last corner and it receives enough water.
• The throw width of 60 inches is covered pretty precisely. And above all: According to my test, there is hardly any overspray, and if so, only by a few inches. The MP-Rotator works very consistently and evenly. With a little fine-tuning by adjusting the sprinkler, you can water a predefined strip very precisely and reliably.

Alternatively, I also tried how the spray pattern behaves with only 30 psi pressure on the sprinkler. Result: The sprinkler works perfectly and evenly even at 30 psi. The throw distance and width are imperceptibly shorter by about 8 to 12 inches, which corresponds very well to the manufacturer’s specifications. Out of interest, I then tried going down to 20 psi and further. Even at 20 psi, the sprinkler still worked quite well, but below that the desired spray pattern was very difficult to maintain.

The pressure measurement directly on the sprinkler was carried out with an MP-Rotator measuring device, which is screwed directly in front of the nozzle.

Water Flow and Precipitation Rate

The water flow I measured of 13 gallons per hour for the RCS and LCS and 26 gallons per hour for the SS is exactly what Hunter specifies. This also matches the precipitation rate I calculated above of 0.58 inches per hour.

Other alternatives for watering a lawn strip

In addition to the strip sprinkler presented above, there are a few other ways to water a lawn strip:

Rotating strip nozzles from Rain Bird

The Rain Bird counterpart to the Hunter MP Rotator strip nozzles are the Rain Bird R-VAN strip nozzles. In terms of spray pattern and application, they are practically identical to those from Hunter.

Watering with MP800 sprinklers with a very short throw

The Hunter MP Rotator MP800 sprinkler is a “normal” circular sprinkler, but can be set to a very short throw of up to 70 inches, so that you can also water lawn strips of at least 70 inches wide. For a strip of 70 x 360 inches, this could look like this (drawn with the DVS Irrigation Irrigation Planner):

The MP800 has a precipitation rate of 0.8 inches/hour, which is about twice as high as the other MP Rotator sprinklers. You should therefore not mix them in a common zone.

Irrigation with a square sprinkler

The principle of this type of sprinkler is familiar from sprinklers that can be placed freely on the lawn: These throw the water high up and slowly swing from left to right and then back again. In this way, the area directly around the sprinkler is also supplied with water quite well. This type of sprinkler is usually not submersible; the only pop-up sprinkler I know of is the OS-140 from Gardena. Since it is possible to set the sprinkler’s throw width very narrowly, up to 40 inches wide, by variably adjusting the nozzles and the throw distance can also be greatly reduced, this sprinkler also represents an alternative for watering a narrow strip of garden. The biggest disadvantage is that the sprinkler is significantly larger than others and therefore requires a significantly larger recess in the ground than others. This is not very attractive visually and could be perceived as disturbing in the lawn.

Spray nozzles from Hunter and Rain Bird

Hunter and Rain Bird also offer classic spray nozzles with a large flow rate and a rectangular spray pattern. At Hunter, these nozzles are called the same as the MP-Rotator nozzles: RCS-515, LCS-515 and SS-530. Like the MP-Rotator side strip nozzles, these are placed on the edge of the strip. Alternatively, Hunter also offers nozzles that are placed in the middle of the strip with the CS-530 and ES-515 nozzles.

The counterpart from Rain Bird is the 15-strip series. Nozzles: 15RCS, 15LCS, 15SST (placed on the edge), 15EST, 15CST (placed in the middle of the strip).

Der Beitrag In the test: Hunter MP-Rotator side strip sprinkler as a solution for watering narrow lawn strips erschien zuerst auf Irrigation Blog for Do-it-yourselfer.

Calculation for an already active irrigation

If the irrigation is already in operation, the easiest way to determine the precipitation rate is to compare the amount of water used and the area irrigated. This should be done separately for each irrigated sector, as the results can differ significantly. You can either simply read the amount of water from an already installed water meter, or you can get a water meter and install it after the water source. You can let the watering run for a whole hour and then compare the meter reading with the one at the beginning of the watering, or you can just let it run for a shorter time and then extrapolate to one hour. The area is either known or can otherwise be determined with a measuring tape.

Calculation formula Precipitation rate = gallon output per hour/area in square foot

In order for the calculation to work, the denominator and counter must be brought to the same units. The following applies:

• 1 gallon water = 231 inch³
• 1 foot² = 144 inch²

So if you water, for example, an area of 20 by 20 feet with 300 gallons water for an hour, then it would apply:

Precipitation rate = 300 * 231 inch³/20 * 20 * 144 inch² = 69,300 inch³/57,600 inch² = 1.20 inches

Attention: This value is an average value and says nothing about how evenly this precipitation is distributed over the area. It may be that some spots receive significantly more water than others, depending on how professionally you have planned your watering (see “square pattern” and “triangular pattern” in the next point).

The rest of the considerations are easy: how much water does the irrigated area need per week and how do you divide up the watering? If you pour the amount of water collected in one irrigation run per week, then you simply divide the required amount of water by the capacity of the irrigation system per hour and thus know the required running time. In the example above, the irrigation system is pouring 300 gallons per hour over a 400 square foot area, which is 0.75 gallons per square foot. The lawn is to receive 0.6 gallons per square foot per week, so watering must run for 1.25 hours (0.75/0.6). So an hour and 15 minutes. If you water twice a week, that would be two times 37 minutes.

Water flow meters at Amazon:

Calculation for a planned irrigation

The sprinklers are positioned in a professional planned irrigation either in the square pattern or in the triangular pattern. The calculation of the precipitation rate also depends on the selected system, whereby the precipitation rate of the triangular pattern is about 10 to 15 percent higher in comparison due to the somewhat higher overlap.

For most sprinkler suppliers, the precipitation rate for both patterns is included in the product descriptions (the triangle symbol indicates the triangular pattern, the square symbol indicates the square pattern). The precipitation rate is given for different water pressure values, which affect the radius and flow rate of the sprinkler and thus also cause a different precipitation rate. An overview of this performance data for numerous sprinklers can be found on the sprinkler performance data page.

Calculating the rate of precipitation in the square pattern

As in the triangular pattern, the following values are required for the calculation:

• The radius of the sprinkler
• The flow rate of the sprinkler

Formula to calculate the flow rate in the square formation = flow rate/(radius*radius)

This formula is best understood using a single square of the square pattern:

Area irrigated in square pattern

The height and width of the square corresponds to the throw distance (radius) of the sprinkler. It receives water from 4 sprinklers in total (marked as black dots in the corners). And each sprinkler waters a quarter circle of the square.

Let’s take the Gardena T200 as an example: This has a flow rate of 150 gallons/hour and a throw distance of 26 feet in 360 degree operation at 29 psi pressure. Before you can calculate, these values have to be converted to the common unit of inches. Again the following applies:

• 1 gallon water = 231 inch³
• 1 foot² = 144 inch²

The flow rate in the square pattern would thus be 150*231/(26*26*144) = 0.36 inches.

This calculation is correct if one assumes that the area is irrigated with sprinklers that irrigate in a full circle. And it is also true for sprinklers with built-in MPR principle such as the Hunter MP-Rotator and for sprinklers that are operated with MPR nozzles. For all of these, the flow rate of a sprinkler is used in the full circle principle. It is therefore assumed that the irrigation looks like this:

Area irrigated in square pattern (within the 4 black dots). The sprinklers irrigate full circles

So each sprinkler that acts on the square runs a full circle. Why is this important? For sprinklers that do not have the MPR principle built in and are not used with MPR nozzles, the precipitation rate is directly related to the circle sector that the sprinklers irrigate. It’s easy to explain why: These sprinklers always release a certain amount of water in a certain amount of time, say 150 gallons per hour. If the sprinkler runs a full circle, it will spread that 150 gallons over the full circle. If, on the other hand, it only runs half a circle, then it runs twice its half circle in the time in which the sprinkler previously ran the whole circle and the lawn in this area receives twice as much water in the same time. With a quarter circle it would even be four times as much. Therefore, with the exception of the MPR sprinklers mentioned above, it is relevant when planning how the irrigation is planned, whether sprinklers irrigate full circles or sprinklers irrigate semicircles. If you plan to use full-circle sprinklers, then the above formula is correct. If you plan your sprinklers to irrigate semicircles or quarter circles, then the result must be multiplied by 2 or 4. So the correct formula is:

Formula to calculate the square pattern for operation in a semi-circle (180 degree sector) = 2*flow rate/(radius*radius)

Formula to calculate the square pattern for operation in a quarter-circle (90 degree sector) = 4*flow rate/(radius*radius)

For this reason, the sprinkler manufacturers indicate in their description for which operation it was calculated. This is mostly for operation in the 180 degree sector, but with some sprinklers also in the 360 degree sector. It is therefore very important to bear this in mind, otherwise the actual precipitation rate may be half or double what is stated in the description.

Derive missing manufacturer information yourself

Sometimes it happens that this information, whether the precipitation rate was calculated with 180 degrees or 360 degrees, is missing for one or the other sprinkler type. This is no problem for you with the formulas given here: Simply take the flow rate and the throw distance and enter them once in the formula for full-circle sprinklers and once in the formula for half-circle sprinklers. Compare the result with the information provided by the manufacturer and you will know which of the two variants was used to calculate it. The same applies to the calculation in the triangle pattern (see next point).

Calculating the rate of precipitation in the triangular pattern

In principle, the same applies here as described above. The two values throw distance (radius) and flow rate are also required, only the formula for the calculation is slightly different:

Formula to calculate flow rate in triangular pattern = radius/(throw*(throw*0.866))

Let’s take again the example of the Gardena T200 with a flow rate of 150 gallons/hour and a radius of 26 feet and again the following applies:

• 1 gallon water = 231 inch³
• 1 foot² = 144 inch²

The flow rate in the triangular pattern would thus be 150*231/(26*(26*0.866)*144) = 0.41 inches

How can the formula be understood? In the triangular pattern, a pattern of many equilateral triangles emerges:

Area irrigated in triangular pattern

In the triangle pattern, each triangle receives water from 6 different sprinklers. The triangle is equilateral, meaning that each of the sides is the same length and the triangle is perfectly symmetrical. And it means that the height of the triangle is 86.6 percent of the side’s width. That’s the 0.866 in the formula above. The area is calculated by multiplying the length of the side by the height.

As before, it is also relevant here whether the sprinklers are operated in the 360 degree circle or in a 180 degree or 90 degree circle. For the 180 degree or 90 degree circle, multiply by 2 or 4 as before:

Formula to calculate the triangular pattern for operation in a semi-circle (180 degree sector) = 2*flow rate/(radius*(radius*0.866)

Formula to calculate the triangular pattern for operation in a quarter-circle (90 degree sector) = 4*flow rate/(radius*(radius*0.866)

Der Beitrag How to calculate the precipitation rate? erschien zuerst auf Irrigation Blog for Do-it-yourselfer.