The components of a head assembly can be few or many depending on the needs of your system. The most common are shown in the drawings below. Use these drawings as a starting point for your basic needs.
These drawings all show the head assembly connected to a hose bib. By using a different backflow devise or one of our adapters you can connect to just about any threaded water source connection.
Parts starting from hose bib--- A
1) Anti-siphon device with hose threads #A015
2) Pressure regulator with hose threads #A013
3) Swivel adapter X .700 poly #LF003
Parts starting from hose bib--- B
1) Anti-siphon device with hose threads #A015
2) Pressure regulator with hose threads #A013
3) 3/4" in-line "Tee" filter #F001
4) Swivel adapter X .700 poly #LF003
Parts starting from hose bib--- C
1) Battery operated hose end timer #9001EZ
2) Anti-siphon device with hose threads #A015
3) 3/4" "Y" Style Filter with hose threads F300
4) Pressure regulator with hose threads #A013
5) Swivel adapter X .700 poly #LF003
What It Does
The head assembly has the job of making the water ready to use by a drip system.
The first thing is to make sure that any water that enters the system stays there. This is the job of the backflow device. The backflow keeps any water which passes it from going back into the water supply lines. This becomes very important if your water supply is your house water! This is very important if you use fertilizer in your drip system. You would not want any fertilizer in the water you drink!
We could have an automatic control valve. In this case, the anti-siphon device should be installed after the battery-operated timer, as shown in illustration C. One of these will let you turn the water on and off automatically. This is more important than most people think. Drip systems when operating are not as easy to notice as conventional sprinklers because all that is coming out is a small stream from each dripper. You would not be the first person to leave a drip system on for a couple of days by mistake! And no, you do not leave drip systems on all the time!! Caution here! Leaving the system on for extended periods of time may cause damage if located in an area where excessive water can do harm.
The third item would be the filter. You may think that drinking water has got to be fine.....you drink it anyway, right? Not really. Even household water can have small particles in it that you do not notice and are big enough to plug drippers. If you notice most faucets in your house have what is called an "airator", which is just a screen. If you ever take one of these out you will most likely find larger particles than you expect. Filters become more important on older homes because of the possible buildup of sediment in the water lines.
Be safe and use a filter!
The fourth item in line is the pressure regulator. Most household water pressure is anywhere between 40 PSI to 60 PSI with some homes even higher. Most homes have a pressure regulator before the water goes to the piping inside the house, which is usually set between 40 to 60 PSI.
Note that a drip system works best with water pressure of 20 to 30 PSI. There are a few reasons for needing less pressure. First is that the outlets, like drippers and microsprinklers, are made to work the best between these pressures. They need to regulate water to a small area trying to wet the area quickly. The second reason is because all the drip components do not use glue or clamps. If you allow high pressure in the system you will have problems with drippers and fittings popping off.
In some circumstances you could need a little higher pressure. This is most common when you will be running PVC pipe from your head assembly to a distant location; it is a common experience to a pressure drop due to the long run of PVC. By the time the water delivered by the PVC pipe reaches the drip components, the pressure could have dropped to an unacceptable pressure. For this we offer adjustable pressure regulators.
Fifth is the polytube adapter. This part simply changes over from the threaded fittings of the head assembly to the Spin Loc or compression type fittings that connect polytube. These could be for 1/4" microtube all the way up to 1" polytube. See our polytube fittings page for the .700 size and our 1/4" microtube size.
Water Flow Issues
You must pick the correct size head assembly components for your water flow needs.
Most homeowners will do just fine with 3/4" size head assembly components but this is an issue to be aware of and there are some tricks we can offer also. The 3/4" size here refers to the components that make up the head assembly as mentioned above. This is the size of the water passage in each of the components. Valves are rated by the pipe size they connect to, as do all the other components.
A 3/4" size head assembly will allow only a certain amount of water flow through it at a given pressure. At a certain point it will not allow any more through no matter what pressure is pushing the water. The real limitation is not always the size of the head assembly, but the size of the pipe it flows into.
Case in point: We have told you the limitation of the .700 size polytube at 25 PSI is about 220 GPH (Gallons Per Hour). Now the 3/4" size head assembly will allow more than this but it will not matter.......unless!
Unless you can divide the water coming out of the 3/4" head assembly into two (2) different .700 size polytubes *BEFORE* it is reduced down from a 3/4" size water passage.
Just in case we lost you here it is again.
The head assembly is 3/4" and the .700 polytube is smaller - so if we can divide the flow while it is still flowing through a 3/4" size opening we can actually supply more than the 220 GPH to a single watering zone!!
To do this we would use part #LF009 which is a 3/4" FNPT swivel x .700 compression x .700 compression fitting. This means that the LF009 has a water inlet of 3/4" in size and divides it into two (2) .700 size water outlets. This allows you to have two .700 polytubes coming from a single head assembly with a maximum flow rate of 1,560 GPH on our 3/4" DC solenoid valve. Please remember this is a specification maximum and not a "real world" maximum. You will have other components which may not allow this type of maximum flow, as an example one of our 3/4" stock filters only allows "up to" 720 GPH. You will also still only be able to have 220 GPH flowing through each .700 polytube so your "real world" maximum would be 440 GPH anyway.
These numbers will also be constrained by your available water supply. This would be your "Bottom Line" maximum flow.
However this does show you a way to get the maximum out of a single head assembly however.
If you will be using a head assembly and connecting it to PVC on the water outlet side make sure the head assembly components are all the same size as the PVC so you can get the maximum flow allowed. This situation could be needed if you have very large areas to water which can all use the same watering frequency and duration. You would have a main line of PVC and connect to it in different locations to run polytube.
Just remember that the available water supply will always be your base limitation and you cannot exceed this no matter what! Also take note that if you have a 3/4" size supply line it will do no good at all to have a 2" size head assembly........just sort of makes sense!
There are many other points we could make here but this will do for all but the commercial grower.
Multiple Zone Assemblies / Manifolds
Multiple zone manifolds are just multiple head assemblies which draw water from the same water source.
What makes this special is the fact that more than one zone is run off a single water supply. This in itself does not seem so special but when you combine this fact with the fact of only using a single backflow and a single filter it adds up to some saved $$'s......Ahhh now your reading closer!
You can combine this money saving option with more savings if you automate the manifold using a single 4 station DC controller to operate up to four DC valves or a 6 station AC controller to operate up to six AC valves!
To really understand this check our valves page, then look at some of the info pages for the pictures of manual and automated assemblies.
This picture here will give you an idea but seeing them all will help you understand even more. This picture is a 4 valve automated manifold which can connect to a garden hose or PVC, model VA006 . As you can see it would weigh quite a bit and even more filled with water so please do not even think of attaching it directly to a hose faucet, something will break before you even turn on the water!
The only real issue we need to address here is the available water supply. You can only have as many valves open (running) at one time as you can supply with the available water. We normally suggest only running one at a time to be on the safe side.
Putting It Together
A few basic rules and tips.
Testing your head assembly
To test your head assembly you should have it connected to the water supply and the water supply on, leave the connection to the drip system off. Turn on the assembly and check the water flow. Not much to see here! If the water flows through strongly it should be fine.
Next connect the drip system and turn on the assembly. This time check for leaks and make sure your drip system is flowing water from all the drippers and microsprinklers. If this is the first time turning on the water to the drip system, make sure to leave the line ends off to flush the entire system of any dirt which may have entered during assembly. Then close off the line ends and check for leaks at the head assembly while making sure the drippers and microsprinklers are working, also.
The joy of a completed job done right!
If you have a manual head assembly you will need to turn the water on and off by hand. If it is a multiple zone assembly you will have some type of ball valves for each zone and again you will have to turn them on and off by hand.
It is a good idea to write down a schedule to refer to. Plants will always do better if watered on a regular schedule with the same watering duration each time.
If you have an automated head assembly, single or multiple, your job will be much easier. Set the controller for each watering zone to water the frequency you like and the duration. That's it!
You should play around with the watering frequency and duration to find the best combination for the plants on each zone. Just remember it is better to start with too much water and cut back slowly until you see the plants look stressed, then increase it just a little. As the plants grow they will need more water so keep this in mind also. Keep in mind that what a plant needs to survive is less than what it needs to grow vigorously. If maximum growth is what you want then make sure to give the plant more water than what you would give for it to just survive, check with a local nursery to see what they suggest for a particular plant in your location