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Installing microsprinklers

Overview
Here are a few things to help you understand how microsprinklers work and why!

Microsprinklers give a spray of water that has droplets much smaller than conventional sprinklers. This allows the water to be absorbed into the ground without causing runoff.
Microsprinklers are normally used in areas of densely planted groundcover where placing individual drippers at each plant just would not make sense. Microsprinklers are also used for trees which have a shallower root system or where the placement of drippers around the tree is prohibitive. Some of this is choice and some is economical good sense. One sprinkler at a tree is much easier to maintain and initially install than many drippers encircling the tree.
Note that when using microsprinklers on trees there will be weed growth because the sprinkler will water a wider area.

Microsprinklers work under the same low pressure that drippers use so in a landscape installation you can use both drippers and microsprinklers on the same lines. Be aware that microsprinklers have much higher flow rates than drippers (and cover a wider area) so make sure to calculate your total water usage as you plan, otherwise you make exceed the 220 GPH max flow of the .700 OD polytube.
Because microsprinklers work under the low pressure they cannot always spray the water the same distance as high pressure conventional sprinklers. Microsprinklers do use a few tricks to overcome this. When microsprinklers spray a *pattern*, which is really the amount of a circle they cover, they use different methods to direct the spray. When doing a full circle, which would be a spray pattern of 360°, microsprinklers sometimes use what is called a "spinner". This spinner uses the force of the water to make itself turn very quickly and this helps to "throw" the water an extra distance. Not all sprinklers use this method but in a nutshell, the ones with the larger rated diameter sprays normally do this. The best example would be our model MS004 & MS005 sprinklers.
Other sprinklers, even when doing a 360° pattern, do not use this method because they do not spray in such a large diameter.

When sprinklers do not use the "spinner" method to spray such large areas or if they only spray a part of a circle, like a half circle (180°) or a 1/4 circle (90°), they use a "deflection" method.
The "deflection" method works by sending a stream of water out of a nozzle which is very small and increases the velocity of the water. The stream then hits the deflector and it is redirected to the spray pattern, as designated by the deflector. Make a note that this is why a sprinkler that uses the "spinner" to get a large 360°spray pattern may have quite a bit smaller distance in the 180° or 90° pattern.

Some sprinklers come with only one spray pattern, while others have interchangeable "deflectors" so you can use whichever pattern you like. A good example again is our MS005 microsprinkler. If a sprinkler has interchangeable deflectors we will normally mention this and sell all the deflectors with the sprinkler.

Some sprinklers can also be adjustable and when they are the adjustment can be for the flow or the pattern.
When the sprinkler is adjustable for the flow, this will also affect the distance or the spray. More flow equals more distance......up to a point. Make sure to check the rating for distance.
If a sprinkler is adjustable for the spray pattern, it will normally not affect the distance. This would not apply to sprinklers with the interchangeable deflectors; they are not classified as "adjustable".

Stakes for Microsprinklers
Just as with conventional sprinklers you need to elevate the sprinkler above the ground and any obstructions so the spray will have a clear path. Microsprinklers can use a few different methods to do this.

The most common stake used is the "Clip Stake". This stake is 12" to 13" long and is pushed into the ground about 3". The sprinkler which is attached to 1/4" microtube (more on this below) is then pushed into a holder on the stake. To make this more clear, the stake has a slot on the side which the microtube snaps into and the sprinkler sits right above this on the end of the microtube. This allows for the use of the clip stake with just about any sprinkler regardless of the sprinkler design. Like we said "just about" any sprinkler. Some sprinklers must use a stake designed just for them and these are well marked in our sprinkler section. Because the clip stake can work with so many different microsprinklers it should always be the first one to consider, it could almost be called a "universal" stake.

The next type of stake would be a "Spike" stake. Some sprinklers are made to fit right onto this stake while others need an adapter. A example of this is our model S002 Spike Stake which works with the sprinkler model MS004 & MS005. These sprinklers have a mounting made to fit into the spike stake directly without the need for an extra adapter. If an adapter is needed on a sprinkler that should use the spike stake it will be either included or noted very clearly.

Another type of stake (if you could call it that) is a Pop-Up sprinkler base, our model S004. This sprinkler pops up when pressure is turned on. Do not get confused with lawn type pop-ups. This pop-up cannot go flush to the level of the ground! It is made to be buried about 1/3 to 1/2 of the body in the ground with the remainder above ground. The extension coming out of the body is about 9" and has the sprinkler mounted on the top. This allows you to use sprinklers in ground cover that might grow too high for a sprinkler on a normal fixed stake to clear. The Pop-up sprinkler would then be hidden when not in use, but will rise above any ground cover when turned on so the spray from the sprinkler will clear the plants. The Pop-up is supplied water by a 1/4" microtube connected on the bottom of the body; this will connect to any 1/2" polytube mainline.

One of the least used in landscaping, but still valuable in certain applications, is called a "Semi-Rigid Riser". This is a very thick walled and stiff piece of 1/4" microtube that has a barb in one end for connecting directly into 1/2" polytube. The other end is open and you would install the sprinkler here. We carry these in only a 6" length as model A003.

Spray Patterns & Diameter
Spray patterns refer to the portion of a full circle which the sprinkler will cover. There are normally 3 patterns. 360° is a full circle, 180° is a half circle and 90° is a quarter circle. Also, some sprinklers will have a "strip spray" which sprays a narrow degree area on opposite sides of the sprinkler.
The diameter is the distance across a circle from one side to the other. When a sprinkler is rated as a 10 ft. diameter it means that the water will wet a circle 10 ft. across one side to the other. Sprinklers can also be rated by the radius of the circle which is the distance from the center to the outside.

Flow Rates
Flow rates are the same as with drippers and are rated in GPH (Gallons Per Hour). Sprinklers will normally have a much larger flow rate than drippers. Ranges we know of off hand go from 7 GPH all the way up to 32 GPH. One thing to keep in mind on the flow rates is to compare them against the diameter the sprinkler gives. Almost always, the larger the diameter sprays the higher the flow rate. This means that the actual amount of water placed in a given area within the spray pattern can stay pretty close between the higher flow and larger diameter sprinklers as the lower flow and smaller diameter sprinklers. This is not always true, but for the homeowner it is close enough to keep as a rule of thumb. What this means to you is that you can intermix large diameter and small diameter sprinklers while watering the same amount of time and the water placed on the entire area should be close to the same. Flow rates also affect the water particle size when it leaves the sprinkler. Very low flow sprinklers can give a very fine spray which could be dispersed by a wind or strong breeze. This is something to keep in mind with all microsprinklers and the time of day you have them on.

Connecting & Installing
Almost all microsprinklers connect to 1/4" microtube with what is called a threaded connection. They have a water inlet stem like a dripper but instead of a barb they use a thread on the stem to hold them in place. Just as a disclaimer here microsprinklers can be placed in 1/2" polytube directly.......but this is very much the exception so we will concentrate on using 1/4" microtube.

To get started we should talk about the differences in 1/4" microtube. The normal microtube used with drip systems can also be used for microsprinklers, but! There is also a thicker walled microtube made just for connecting microsprinklers and their "Threaded Connections". We mention the threaded connections because the thicker walled tubing is a little stiffer and this helps hold the sprinklers better. The normal 1/4" microtube has an inside diameter of .156" and an outside diameter of .245". The thicker walled microtube has an inside diameter of .160" by an outside diameter of .270".
Because of this thicker wall on the tubing there is less chance of the sprinkler working itself loose due to extreme heat or higher pressure. We mention the higher pressure because in some situations using an adjustable pressure regulator and long lines you could have higher pressure at the start of a line. This is mostly in commercial applications, but many homeowners have multiple fruit trees which might run into this problem.
One more tidbit on the thicker walled tubing As of this writing we only carry the thick walled microtube in model T008 tubing precut in a 24" size, longer coils should be available at a later date. Custom cut lengths are available on orders of 1,000 pieces or more. Contact us for quotes.
All the sprinklers we sell which have tubing already attached use the thicker walled tube.
To actually make the connection from 1/2" or larger polytube you will first use a 1/4" connector barb model SF001. This barb will have one end fit into a hole in the 1/2" or larger polytube made by one of our punches. The other end will fit into one end of the microtube which runs to the microsprinkler. You will then run the microtube to the sprinkler and connect it. Using one of the staking methods mentioned above you can place it in the correct location.
You should try to keep the 1/2" polytube sort of close to where the sprinkler will be placed. If you start to run the microtube from the 1/2" polytube too far, you can run into pressure drops that will affect the performance of the sprinkler. We suggest going no more than 3 or 4 feet with the microtube. You can go farther, and if it works for your application that's fine.

When installing the microsprinkler into the 1/4" polytube, screw it in until the tube meets the base of the sprinkler. Try not to screw it in too much because you will strip the threads made in the microtube wall and this will weaken the hold of the sprinkler.
If you need to replace a sprinkler make sure to cut off about 1/2" of the end of the microtube. When the sprinkler is threaded into the microtube it causes the microtube to expand slightly and it is better to get rid of this small piece and start new.

Troubleshooting

  • Very little flow comes out of the microsprinkler nozzle.
    This is caused by some kind of blockage of the water to the microsprinkler. First check to make sure your flow is getting to the microsprinkler itself. Disconnect the microtube from the microsprinkler and turn on the water. If you get a good flow of water then there is dirt or some blockage in the microsprinkler itself. With some microsprinklers you can blow into the water outlet and push the debris back out. You should also look into the water inlet and outlet to try and spot something. If you cannot clean out the debris you may have to replace the sprinkler, this is why we always suggest flushing the lines well before start up and using a good quality filter!
    If you disconnect the tubing to the microsprinkler and you do not get much flow the problem is either in the connection to the mainline polytube or the mainline polytube itself. Check to make sure that the hole in the polytube is made all the way through and nothing is blocking the water inlet of the 1/4" barb. You can try blowing back through the microtube. This may dislodge debris blocking the barb.
  • When I change from a 360° pattern to a 180° or 90° pattern, the distance of spray is much less than before.
    This is normal and is mentioned in the above section "Overview" on the top of this page.
  • All my microsprinklers give what seems like a very weak flow and do not come near the rated diameter.
    Check your sprinklers flow rates and add all the flow rates together. Make sure you have not exceeded your water supply flow rate or the rated flow rate of the 1/2" polytube you are using. This is a common mistake and will give you very little flow from all the sprinklers.
    You may also want to check your 1/2" polytube and make sure there is not a kink or partial kink in it.
  • I keep finding sprinklers which have popped off the microtube.
    This can be caused by not using the thicker walled microtube, animals running through the irrigation and kicking off the sprinklers or high pressure. Check your pressure regulator or if not using one install one.
    The animal thing sounds far fetched but one of our employees ran into this with a dog running through the planted area and kicking the sprinklers, occasionally knocking one off. We could not figure this out at first and thought they were popping off for other reasons. Our employee then saw his dog actually knock one off.......stranger things happen!
  • No animals, pressure is good and I use the thicker walled microtube. But some sprinklers still pop off.
    Try taking the sprinkler off the microtube and cutting off about 1/2" of the end which had the sprinkler in it. Make sure when reinstalling the sprinkler not to screw it on too far and strip the threads the microtube creates inside the microtube wall.
  • The sprinkler wobbles around when running.
    If using a clip stake make sure the sprinkler is all the way down to the "clip" on the stake which holds the microtube. If you are using models MS004 or MS005 microsprinklers then you must use stake model S002.
  • No water comes out of any microsprinklers......turn on the water! (Ahhh we had to say this!)

 


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