Tag Archives: master valve

Review: Superior Model 3200 & 3300 Automatic Master Valves

The Superior model 3200 & 3300 series master valves are solid-brass, electric 3-way solenoid, MASTER VALVES.   These valves are designed to be extremely sturdy and to open and close reliably under extreme conditions.  The 3-way solenoid design allows these valves to open and close with zero flow through the valve.  While designed for the demanding task of being a master valve, these valves are often used for other purposes where a high quality, reliable valve is needed, especially in unique situations.  These master valves are available as normally-closed (3200 series) and normally-open (3300 series) configurations.

Superior 3200 Series Brass Master Valve
Superior 3200 Series Brass Master Valve

Basic Background on Master Valves:

What is a Master Valve?  Master valves (aka: main valve, primary valve) are utilized on irrigation systems to turn on/off the entire water supply to the irrigation system.  They are often used as an automated emergency shut-off valve working in conjunction with a controller unit that utilizes flow and/or pressure sensors to detect problems in the irrigation system.  When a problem is detected by the control unit the master valve is closed, shutting off the water supply to the entire irrigation system.  This reduces any further damage and/or water waste until the problem can be fixed.  For larger irrigation systems the irrigation maybe divided into multiple sections with a separate master valve for each section.    A master valve is typically installed as close as possible to the irrigation water source.

In addition to being used as an emergency shut-off, master valves are being increasingly use as a secondary fail-safe, shut off valve,  to prevent wasted water if one of the zone valves should leak.  When used as a fail-safe the master valve is closed any time the irrigation system is off, thus shutting off and depressurizing the entire irrigation system.

Why not use a normal solenoid valve as a master valve?  While any automatic valve could be used as a master valve, in most situations where master valves are used a higher level of quality, as well as special features that help the valve to operate more  reliably, are desirable.

This is a rather brief description of master valves.  For more details and a list of the pros and cons of master valve use, see the article on Master Valves.

Normally-Closed valves open when the solenoid is energized.   Most automatic irrigation valves are normally-closed, like the 3200 series.   When power is applied to the solenoid, a normally closed valve will open.   The valve closes when the power to it’s solenoid is cut off.  Normally-closed is the industry standard, so if a valve description doesn’t say which type it is, it is usually safe to assume it is the normally-closed type.  An advantage of normally-closed valves used as master valves is that they close when there is no power, ie: a power failure, or if the wires to the valve are cut or broken.  The normally-closed valve will shut-off the water supply in any of those situations.

Normally open valves close when the solenoid is energized.  If there is no power applied to the solenoid a normally open valve will open and remain open until power is applied.  Sometimes you need a  valve that closes when power is supplied to it.  A normally-open valve fills that niche need.

3-Way Solenoid or “No Minimum Flow” feature.  The 3-way solenoid on this valve allows it to vent the water in the diaphragm chamber to the atmosphere.  In laymen’s language that means that each time the valve opens or closes it spits a few tablespoons or so of water out of the back of the valve onto the ground.   Without getting technical, what this does is to allow the valve to open and close at a very wide range of flow, thus the “No Minimum Flow” claim.  For example Superior makes two more or less identical normally-closed master valves.  The 3000 series without the 3-way solenoid has a flow range of 5-320 GPM.  The 3200 with the 3-way solenoid has a flow range of 0-360 GPM.   This wider flow range, especially the No Minimum Flow, is an important feature for a master valve that is going to be used as an emergency shut off.  For example, let’s say we have an irrigation system, all the valves are off, but one of the pipes has sprung a leak and is dripping one gallon of water an hour.  A normal solenoid valve would not be able to close and stop the leak, because normal valves can’t close if there is less than 5 GPM of flow.   However a master valve with a 3-way solenoid will be able to close, and will stop the leak.

Drainage needed.  With a 3-way valve the designer needs to make a provision for the small amount of water that will spit from the valve each time it opens or closes.   In most cases the  valve is installed over a small pit with a few inches of gravel in it to absorb the discharged water.  If installed over a non-absorbent surface like concrete,  a drain needs to be provided for the water.

Superior 3200 Spitting Water From 3-Way Solenoid Outlet
Superior 3200 Spitting Water From Outlet Below 3-Way Solenoid

Not just for use as a master valves.  These valves are suitable for use in almost any situation where a high reliability valve is needed.  While it is called a “master valve” the usage does not need  to be limited to master valves, they could be used as zone valves for a sprinkler system for example.  A common use for normally-open valves like the 3300 is in automating the flush cycle of filters where they are used to redirect the water flow into the flush channel during the flush cycle.

RW Option:

The 3200 & 3300 series valves also are available with a “RW” option for use on recycled water systems.  The RW option adds a purple cross handle on top of the valves to indicate the use of recycled water.

Features of the Superior 3200 & 3300:

  • ¾”,  1″,  1½”,  2″,  2½”, and 3″ sizes
  • The 3200 series is a normally-closed design. This means the valve opens when power is supplied to the solenoid.
  • The 3300 series is a normally-open design.  This means the valve closes when power is supplied to the solenoid.
  • No Minimum Flow allows operation at no flow (3-way solenoid.)
  • Flow rates 0-360 GPM depending on valve size (see charts on the Superior website.*)
  • Rated for 20 – 150 PSI operating pressure.
  • Solid Brass body and cap.  (Plastic plate for the No Minimum Flow feature located between body and cap.)
  • Solenoid can be removed from the valve without cutting the wires.  (Makes maintenance easier.)  However you do need to disconnect the copper tube from the top of the solenoid to remove it on these models.
  • Slow closing.
  • Flow control with a brass cross-style handle.
  • EPDM rubber for long life.
  • Various solenoid voltages and wattages available, as well as latching solenoids.
  • Optional with British Standard Pipe Threads on inlet/outlet.
  • Separate rubber valve seat washer and diaphragm.
  • Optional purple recycled water handle.

* While this valve will work at close to no flow, like all solenoid valves it should be the proper size based on the normal flow expected through the valve.  Always base the valve size on the expected flow.  Do not select valves based on the pipe size!  It is very common for the valve to need to be a different  size than the pipe.

Review:

The Superior Valve is one of those products that years of use has shown to be a reliable, rock solid product.  For this review the test valve was a 1″ size sample of the Superior 3200 normally-closed master valve.  The normally open 3300 version of the same valve was not tested however it would be expected to perform similar.  The 3200 was installed on the test stand and operated at both 30 PSI and 110 PSI inlet pressures, as well as various flow rates.  The valve was tested with the manual flow control stem fully open and then tested again with it throttled to a partially closed position.

Results:  The 3200 normally-closed master valve opened smoothly and quickly at all tested flows and pressures when the solenoid was energized.  It also opened smoothly when using the manual bleed screw.  Note that when opened and closed manually using the bleed screw the 3-way solenoid is bypassed.

When the solenoid was de-energized (power turned off) the valve closed as it should at all tested pressures and flow rates.

To test the no minimum flow feature the valve was tested while operating a single 1 gallon per hour drip emitter at 30 & 100 PSI with the flow control in the full open position.   It took the valve a couple of minutes but it did completely close when the power to the solenoid was turned off.   While use of the manual bleed screw bypasses the “no minimum flow” feature, out of curiosity this same test was repeated using the manual bleed and the valve still closed at the 1 GPH flow!

Summary: These test results are about as close to perfect as is possible for any valve.

While not tested, the 3300 series normally-open valve would be expected to perform similar to the 3200.

The Superior 3200 & 3300 valves have a separate rubber seat washer that is not part of the valve diaphragm.  With most valve brands the seat washer and diaphragm are a single rubber piece, thus if the seat becomes worn you must replace the entire diaphragm/seat assembly.  The concentrated flow of water over the seat washer in a solenoid valve creates a lot of wear on the seat washer and the seat washers typically fail long before the diaphragm does.  This valve’s separate seat and diaphragm design means if the seat washer becomes pitted you can simply replace the separate rubber seat washer without the need to also replace the diaphragm.  In fact, the seat washer is reversible, so unless it is really pitted  badly you can just flip it over and reuse it without replacing it at all!

One last note on Superior valves… they have really great fully illustrated repair and  troubleshooting guides available on the Superior Valve Website.  That is the kind of “after the sale care” that explains why many professional groundskeepers are loyal customers.

Superior 3200 on the test stand.
Superior 3200 on the test stand.

About Superior Controls

Superior Controls is one of the original automated irrigation companies, and one of the first manufacturers of electronic solenoid valves for irrigation use.  They have been producing high quality brass solenoid valves for many, many years.  They also manufacture Irrigation Controllers for operating the valves.  Superior Controls merged with Buckner Company (another of the pioneer sprinkler manufacturing companies that specializes in brass products) in 2000 and both were acquired by Storm Manufacturing Group in 2006.

Review: Superior Model 3000 & 3100 Automatic Master Valves

The Superior model 3000 & 3100 series master valves are solid-brass, electric solenoid, MASTER VALVES.   These valves are designed to be extremely sturdy and to open and close reliably under extreme conditions.  While designed for the demanding task of being a master valve, these valves are often used for other purposes where a high quality, reliable valve is needed, especially in unique situations.  These master valves are available as normally-open (3100 series) or normally-closed (3000 series) configurations.

Superior 3100 Brass Master Valve - 1" size
Superior 3100 Brass Master Valve – 1″ size

Looking for a Master Valve?

It’s rather strange to start a review off by redirecting you to a different product, however if you are looking for a Superior brand master valve then the Superior 3200 or 3300 series should really be your first choice.  The reason why is that the 3200 & 3300 master valves open/close reliably at ANY flow.  It’s important for master valves to be able to shut down the system at any flow, no matter how high or low the flow may be.  However, the 3200 & 3300 also spit water out of the valve each time they open/close which is a problem in some situations.  In those situations the 3000 and 3100 valves reviewed here serve as the next best option.

Basic Background on Master Valves:

What is a Master Valve?  Master valves (aka: main valve, primary valve) are utilized on irrigation systems to turn on/off the entire water supply to the irrigation system.  They are often used as an automated emergency shut-off valve working in conjunction with a controller unit, and utilizing a flow and/or pressure sensors to detect problems.  When a problem is detected by the control unit the master valve is closed, shutting off the water to the entire irrigation system.  For larger irrigation systems the irrigation maybe divided into multiple sections with a separate master valve for each section.    A master valve is typically installed as close as possible to the irrigation water source.

In addition to being used as an emergency shut-off, master valves are being increasingly use as a secondary fail-safe, shut off valve,  to prevent wasted water if one of the zone valves should leak.  When used as a fail-safe the master valve is closed any time the irrigation system is off, thus shutting off and depressurizing the entire irrigation system.

Why not use a normal solenoid valve as a master valve?  While any automatic valve could be used as a master valve, in most situations where master valves are used a higher level of quality, as well as special features that help the valve to operate more  reliably, are desirable.

This is a rather brief description of master valves.  For more details and a list of the pros and cons of master valve use, see the article on Master Valves.

Normally-Closed valves open when the solenoid is energized.   Most automatic irrigation valves are normally-closed, like the 3000 series.   When power is applied to the solenoid, a normally closed valve will open.   The valve closes when the power to it’s solenoid is cut off.  Normally-closed is the industry standard, so if a valve description doesn’t say which type it is, it is usually safe to assume it is the normally-closed type.  An advantage of normally-closed valves used as master valves is that they close when there is no power, ie: a power failure, or if the wires to the valve are cut or broken.  The normally-closed valve will shut-off the water supply in any of those situations.

Normally open valves close when the solenoid is energized.  If there is no power applied to the solenoid a normally open valve will open and remain open until power is applied.  Sometimes you need a  valve that closes when power is supplied to it.  A normally-open valve fills that niche need.

Not just for use as a master valves.  These valves are suitable for use in almost any situation where a high reliability valve is needed.  While it is called a “master valve” the usage does not need  to be limited to master valves, they could be used as zone valves for a sprinkler system for example.  A common use for normally-open valves like the 3100 is in automating the flush cycle of filters where they are used to redirect the water flow into the flush channel during the flush cycle.

RW Option:

The 3000 & 3100 series valves also are available with a “RW” option for use on recycled water systems.  The RW option adds a purple cross handle on top of the valves to indicate the use of recycled water.

PRS Option:

The 3100 series valves are available with a optional “PRS” Pressure Regulating System (PRS.)  This add-on option turns the valves into pressure regulating valves that can reduce and maintain the downstream pressure at a set level.

A couple of warnings for those not familiar with how pressure regulating valves work:

  • A pressure regulator can’t increase the pressure above what is already present.  No pressure regulator can increase water pressure, you need a pump to do that.
  • As with all hydraulic-powered pressure regulators, the outlet pressure setting needs to be about 15 PSI lower than the input pressure in order for the regulating feature to work accurately.  If the pressure drop through the valve is less, then the downstream outlet pressure may vary up and down over a range of several PSI rather than stay steady at the set pressure.  Example: if the valve inlet pressure is 80 PSI then the valve outlet pressure has to be set to 65 PSI or less (80 – 15 = 65).

Features of the Superior 3000 & 3100:

  • 3/4″, 1″, 1 1/4″, 1 1/2″, 2″, 2 1/2″, and 3″ sizes
  • The 3000 series is a normally-closed design. This means the valve opens when power is supplied to the solenoid.
  • The 3100 series is a normally-open design.  This means the valve closes when power is supplied to the solenoid.
  • Flow rates 5-320 GPM depending on valve size (see charts on the Superior website.*)
  • Rated for 20 – 200 PSI operating pressure.
  • Solid Brass body and cap.
  • Solenoid can be removed from the valve without cutting the wires.  (Makes maintenance easier.)  However you do need to disconnect the copper tube from the top of the solenoid to remove it on these models.
  • Slow closing.
  • Flow control with a brass cross-style handle.
  • EPDM rubber for long life.
  • Various solenoid voltages and wattages available, as well as latching solenoids.
  • Optional with British Standard Pipe Threads on inlet/outlet.
  • Separate rubber valve seat washer and diaphragm.
  • Optional purple recycled water handle.
  • Optional Pressure regulation module (available on 3100 series only).

* All solenoid valves must be the proper size for the flow through the valve.  Always base the valve size on the expected flow.  Do not select valves based on the pipe size!  It is very common for the valve to need to be a different  size than the pipe.

Review:

The Superior Valve is one of those products that years of use has shown to be a reliable, rock solid product.  For this review the test valve was a 1″ size sample of the Superior 3100 normally-open valve.  The normally closed 3000 was not tested however it would be expected to perform similar.  The 3100 was installed on the test stand and operated at both 30 PSI and 110 PSI inlet pressures, as well as various flow rates.  The valve was tested with the manual flow control stem fully open and then tested again with it throttled to a partially closed position.

Test Summary: The Superior 3100 performed excellent in all tests.

Test Results:  The normally-open Superior valve opened as it should when the power to the solenoid was shut off (ie: this is a normally OPEN valve, it closes when power is applied to the solenoid.)  It opened quickly after the power was shut-off at all of the flow rates and pressures tested.

When the solenoid was energized the test valve closed as it should.  The manufacturer rates the minimum flow for this valve as 5 GPM, and the 1″ test valve closed at both 30 and 110 PSI with no need to throttle the flow control.  To see what would happen if the valve was pushed beyond it’s normal limits the valve was tested again at a flow of 1 GPM, far below the manufacturer’s recommended minimum flow.  The valve did not close at this low flow when the flow control was fully open, however with only a small amount of throttling of the flow control it did close.  This shows that the flow control feature on the 3100  allows this valve to be very adaptable to unexpected conditions where it is pushed beyond the norm.

The tested 3100 series valve is normally open so it does not have a bleed screw for manual operation (a bleed screw won’t work with a normal solenoid valve.)  To manually close the valve you simply turn the flow control handle on top of the valve until the flow is shut off, just like you would with a standard manual garden valve.

While not tested, the 3000 series normally-closed valve would be expected to perform similar to the 3100.  The 3000 series does have a manual bleed screw on it.  The optional RW and PRS features were not tested for this review.

The Superior 3000 & 3100 valves have a separate rubber seat washer that is not part of the valve diaphragm.  With most valve brands the seat washer and diaphragm are a single rubber piece, thus if the seat becomes worn you must replace the entire diaphragm/seat assembly.  The concentrated flow of water over the seat washer in a solenoid valve creates a lot of wear on the seat washer and the seat washers typically fail long before the diaphragm does.  This valve’s separate seat and diaphragm design means if the seat washer becomes pitted you can simply replace the separate rubber seat washer without the need to also replace the diaphragm.  In fact, the seat washer is reversible, so unless it is really pitted  badly you can just flip it over and reuse it without replacing it at all!

One last note on Superior valves… they have really great fully illustrated repair and  troubleshooting guides available on the Superior Valve Website.  That is the kind of “after the sale care” that explains why many professional groundskeepers are loyal customers.

Superior 3100 Valve on the Test Stand
Superior 3100 Valve on the Test Stand

About Superior Controls

Superior Controls is one of the original automated irrigation companies, and one of the first manufacturers of electronic solenoid valves for irrigation use.  They have been producing high quality brass solenoid valves for many, many years.  They also manufacture Irrigation Controllers for operating the valves.  Superior Controls merged with Buckner Company (another of the pioneer sprinkler manufacturing companies that specializes in brass products) in 2000 and both were acquired by Storm Manufacturing Group in 2006.

Irrigation Valves

This page explains everything you need to know about irrigation valves!

There are many different kinds of irrigation valves available. You will need at least two different types for your irrigation system.

1. Emergency shut-off valve:

This valve should be installed at the closest point possible to your water source, that is, the location where you tap in for the irrigation system. Without this valve you will need to shut off the water to the entire house when you want to work on the mainline or irrigation valves. The most commonly used valves for this purpose are “gate valves” because they are inexpensive. Unfortunately the cheap gate valves you’re likely to find in your local hardware store also tend to fail after a very short period of time.  I recommend that you use a “ball valve”, or if you need a really big shut off valve (over 3 inch size) use a “disk valve” or “butterfly valve”. These cost a bit more but are much more reliable and will last several times longer. So if you pay twice as much for a ball valve it’s probably still the best deal! If you want to use a gate valve make sure that it is a “wedge” type and buy a good quality one (it will probably cost more than a ball valve.) There’s nothing worse than trying to repair a system when you can’t shut off the water completely.  OK, that’s about all you need to know about emergency shut-off valves.  The rest of this page is about Irrigation Control Valves.

2. Irrigation Control Valves:

These are the valves that turn on and off the sprinklers, they also may be used for drip irrigation systems. Other names sometime used for them are irrigation valve, sprinkler valve, solenoid valve, and lawn valve. Sometimes they are incorrectly called Garden Valves.  A garden valve is a manual valve that you connect a garden hose to.

Globe Valves vs. Anti-Siphon Valves

You have two basic styles of control valves to choose from.

 sprinkler10a

Globe or angle valve:

This valve is available in any size and is commonly installed underground in a box or vault. Since it doesn’t incorporate a backflow preventer you must provide one separately. See the article on backflow preventers. The globe style valve is the most common used valve on commercial and larger size sprinkler systems.

Anti-siphon valve:

Available only in 3/4″ and 1″ size. This is the most common used valve style for homeowners. The anti-siphon valve incorporates a backflow preventer into the valve. This saves a considerable amount of money, as backflow preventers are very expensive. The anti-siphon valve MUST be installed above ground and MUST be at least 6″ higher than the highest sprinkler head. This means that if you want to use anti-siphon valves you will have to locate the valves at the highest point in your yard, and run a water supply pipe to them from the water source (this water supply is called a “mainline”). The mainline pipe leading to the anti-siphon valves should be buried 18″ deep to protect it.

Valve Operation/Control Systems

Manual, Hydraulic and Solenoid Valves:

The sprinkler valves may be manually operated or they can be remotely controlled (automatic valves.) Manual control is simple, the valve has a handle that you use to turn it on and off using your hand as the power source. Remote control valves are either electric or hydraulic operated using a timer or other signaling device to tell them to open and close. Today almost all of sprinkler control valves are electric powered solenoid valves. The electric solenoid valve operates on 24 volt alternating current (vac) and is turned on and off by a timer called an “irrigation controller” or often just “controller”. Anti-siphon, globe, and angle valves styles are all available as automatic valves.

Solenoid Valve and Controller Compatibility

Pretty much all 24 volt valves and controllers are compatible with each other.  The most common exception to this rule is valves operated by controllers that are battery or solar powered. (By battery powered I mean they are not plugged into a power source other than the battery.  Many controllers have a battery to prevent program loss in case of a power failure, these are not “battery operated”.) So in most cases you can buy a brand “X” controller and it will work fine with brand “Y” valves. You can even mix two or more brands of valves together if for some reason that appealed to you.  For example the irrigation system where I test valves and controllers has many different brands all running together.  If the valve is not “universal” or compatible it will typically have a warning on the packaging.

Flow Control

I strongly recommend that if you are going to use automatic valves, you select a valve model that has a manual flow adjustment control feature on it. Don’t confuse the flow control with a manual on/off switch. The flow control is a separate handle (sometimes a screw) in addition to the manual on/off control on the valve. This flow control feature is not found on many of the less expensive “budget” valves. The flow control bypasses the automatic valve features allowing the valve to be closed in an emergency by turning a handle just like a standard manual valve. More important is that it also allows the valve to be “throttled”, that is, the water flow may be adjusted to any rate desired. This ability to adjust the flow rate is very useful in many different situations, both when installing your sprinkler system and later when managing it.  It can literally make the difference between being able to make a troublesome valve work and having to remove and replace it!  I very strongly suggest that this is a feature worth the extra cost.

why

  • Using the manual flow control you can manually force the valve closed if it sticks open. The manual on/off switch will not close the valve if it is stuck open. Failure to close automatically is one of the most common valve problems, so there’s a good chance that someday you will use the flow control to force closed a valve that is stuck open.
  • If your flows are on the low end of the valve’s operation range, it may be helpful to throttle down the flow control to make the valve close faster and more reliably. Without the flow control feature you may have a lot of problems in this situation, you will probably have to replace the valve.
  • Partially closing the flow control will make the valve close faster, which is not something you want to do normally, but sometimes it is desirable. On automatic systems it is common for the next valve to open before the previous one fully closes. The resulting loss of pressure due to two valve circuits being on at the same time can cause the first valve to never fully close. A flow control on the valve can help correct this problem.
  • Buy valves with the flow control feature.  Just do it.  Don’t be one of the many people who later makes some lame excuse to me, like “the guy at the store, who normally works in the paint department but was filling in for the day on the irrigation aisle, said it was a waste of money!”

Should You Use Metal or Plastic Valves?

Sprinkler valves come in both brass and plastic models. Most valves used today are plastic, but brass is not out of the picture. There is no doubt that a brass valve will last longer in most situations, especially if installed above ground in the sunlight. From an operational point of view both are reliable, especially for automatic systems. For manual valves my experience is that plastic valves wear out fast and have a very short life. Brass will last much longer. If you use plastic valves above ground you may wish to consider building a cover for them to protect them from sunlight, which can destroy the plastic over time.

Two types of plastic material are used for valves. Glass-reinforced nylon is the best, it is tougher, more resistant to impact, and has a higher pressure rating. PVC is used for lower cost valves, it still is pretty strong, although that really depends on how thick the plastic is! A few valves use ABS plastic or polyethylene, especially for minor parts like screws or caps. Both of these plastics are less strong and are typically used for parts with little stress on them. I recommend avoiding valves with “solvent weld” connections (the pipe glues directly into the valve.) If the valve fails, they can be difficult to replace. Only the cheapest valves come with solvent weld connections. Hmmm… cheap valves fail more and with glued ends are harder to replace- sounds like a bad idea.

Jar Top or Traditional Top Held on with Screws?

OK, just personal opinion here, but I don’t see any advantage to a jar top valve.  Yes, they seem to work as well as a top with screws holding it on.  They primarily are only found on cheaper valves.  The only selling point I have heard for them is that they are supposed to be faster to open for repairs.  Are you repairing it that often?  I hope not! But I guess if it is a cheap valve…?  My experience is that by the time the valve is old enough to need repairs the jar top has seized up and it takes a strap wrench to get the top off.  Personally I prefer using a simple screwdriver to remove a few screws as opposed to wrestling with a strap wrench in a tight spot like a valve box.

Maintenance

Today’s valves are pretty maintenance free. Almost all automatic valve failures result from installation or design problems. Ignore the following and you will hate your valves regardless of what type or brand you buy!

Tip
Join the “Hall of Regrets”! Simply ignore the following advice, then send me your “I’m an idiot, I wish I’d listened…” sob story. I’ll add it to my collection and shed an alligator tear or two for you!

  • Dirt in the irrigation pipes. Inside the valve there are very small water passages that lead to and from the solenoid. Water must flow freely through these small passages. If a grain of sand or glob of algae gets into these passages it can block them and the valve will fail to open or (more likely) fail to close. It is critical to flush all the dirt out of the pipes before installing the valves. A 100 to 200 mesh filter installed at the water source connection can also help keep out contaminates that come in with the water supply. You may be surprised to learn that most water companies have considerable amounts of sand in their pipes. When you install a new sprinkler system the higher flows stir up this sand and then it gets into your new system. That’s why I suggest to you in the installation tutorial to flush for so long. You have to get the sand out of both the sprinkler system pipes and the water supply pipes! I can’t stress this enough! It’s like a cheap low-flow toilet. You have to flush, flush, and flush again!
  • Almost all valve solenoid failures are caused by water getting into the solenoid. The water gets into them through the wires. The solenoid wires have multiple strands of wires twisted together with insulation around them. Because they are twisted there are very small gaps between the wires which form passages along the length of the wire. Water is sucked up through these small passages and deposited into the solenoid by capillary action. Thus it is critically important that the wire splices on the valves be completely water proof so that water can’t be sucked into the solenoid through the wires. You should water-proof the wire splices right after you test the valves! No kidding, a single drop of water on the bare valve wire end can be quickly sucked up into the solenoid and will ruin the solenoid. The Installation Tutorial has more on this.

Valve Size and Pressure Losses:

Emergency Shut-Off Valve:

The pressure loss through the emergency shut-off valve is not significant enough to worry with. We will ignore it. The emergency shut-off valve should be the same size as the pipe it is installed on. If a smaller size shut-off valve is used then you do need to worry about losing pressure through the valve. Probably about 2 PSI would be a safe assumption of the pressure loss.

Automatic Valves:

WARNING!!! If you use the wrong size automatic valve, the valve may not work! READ THAT AGAIN! Let it sink in. The correct valve size often will not be the same size as the pipe it is connected to.

why
The pressure loss in an automatic solenoid valve is the primary energy source used by the valve to open and close the valve.  The electricity sent to the valve solenoid is just used to jump-start the process, the real force used is the water pressure.  If the valve doesn’t have enough pressure loss it will not have the energy needed to close by itself.  Always size automatic valves based on the flow rate using the manufacturer’s chart as a guide. Never assume that the valve should be the same size as the pipe! It is very common for the valve to be a different size than the pipe it is installed on. I have seen some rare cases where a 3/4″ valve was the proper size for the flow through a 2″ pipe!!! If you absolutely must guess, use the next solenoid valve size smaller than the pipe size and assume a pressure loss of 6 PSI. Never guess if your flow is less than 5 GPM, always use a chart! Many automatic valves won’t work at all at flows below 5 GPM!

The size of the automatic valves is determined by the manufacturer’s recommended flow range, together with the pressure loss through the valve at the selected flow. You will need to get the valve manufacturer’s flow chart for the model of valve you plan to use. This information should be on the valve packaging. If you can’t find it on the package, try the valve manufacturer’s website or ask for a data sheet on the valve at the store where you buy the valve. (At discount home improvement stores you are likely to get a blank stare from the employee if you ask for a data sheet!)

Some valves don’t appear to have data sheets available anywhere, so as a last resort I’ve assembled some data for you based on my own research for some of the more popular ones. You will find it in the reviews on this website, Click Here.  That said, if the valve manufacturer doesn’t provide this necessary information it shows an extreme lack of professionalism, I would be very reluctant to use the product!

If you can’t find pressure loss and flow range information for the valve you want to use, I strongly suggest you use a different brand of valve. After the valve is installed is not a good time to discover it’s the wrong size and won’t open or close automatically!

Example: let’s say you are going to use an automatic anti-siphon type valve. Your Design Flow is 20 GPM, so for now we will assume the flow through the valve will also be 20 GPM. (If it turns out the flow will be less, you can resize the valve later.) The manufacturer’s flow chart would look something like this:


 

Doesn’t Work Valve Company, Inc. – Valve Performance Data

5 GPM 10 GPM 15 GPM 20 GPM 25 GPM
3/4″ Anti-Siphon Valve 5.0 PSI 5.5 PSI 6.0 PSI 8.0 PSI
1″ Anti-Siphon Valve 2.5 PSI 3.5 PSI 3.0 PSI 4.0 PSI 9.0 PSI

Warning: The chart above is not real. DO NOT USE THESE VALUES!


The example chart above tells us that the pressure loss for our valve at 20 GPM flow would be 8.0 PSI if we used a 3/4″ valve and 4.0 if we used a 1″ valve. So we could use either one. The pressure loss information from the chart would be the number that you write into your Pressure Loss Table on the “_____ PSI – Valves” line. So if we decided to use the 3/4″ valve, the value would be 8 PSI. But what if after adding all the pressure losses in the loss table, you discover that the losses are too high? In that case you could go back and change to a 1″ valve. That would reduce the pressure loss down to 4 PSI, rather than 8. With that said, as a general rule I try to avoid losing more than 6 PSI through a valve. So I would not use a 3/4″ valve in the example above if it were my sprinkler system. Why? Valves need pressure drop for them to work correctly, but really high pressure losses are hard on the valve. As the pressure loss through an automatic valve increases, the speed with which the valve closes also increases. Thus a high pressure loss can cause the valve to snap closed extremely fast, and that is bad for the entire sprinkler system. Plus the water is moving extremely fast through the valves at those higher pressure loss rates, resulting in more wear on the valve seats. The result is that the valve will fail earlier.

If you looked closely at the chart above you may have noted a couple of interesting items. First, and most obvious, is that no pressure loss is given for a 3/4″ valve at 25 GPM. This is because that flow is outside the acceptable range for the valve. You should not use the valve for that flow. The next item is less obvious, but if you look closely, you will notice the pressure loss for the 1″ size valve is less at the 15 GPM than it is at the lower 10 GPM flow!  No, it isn’t a mistake.  It is very common for valves to have higher pressure losses at very low flows, so don’t panic if you notice this on a flow chart, it’s not a misprint.

Can a valve be smaller than the pipe it is connected to?

As you move through the tutorial you will find that even though the valve will handle a certain flow, that flow is often too high for the same size of pipe. So it is very common to have a valve that is one, or even two, sizes smaller than the pipe it is installed in. In fact it is so common that they actually make special pipe fittings (connectors) for this. For example they make a PVC plastic male adapter that glues onto 1″ pvc pipe, but has 3/4″ threads to allow you to install a 3/4″ valve on a 1″ PVC pipe. They also make one that glues onto 1 1/4″ pipe but has 1″ threads.

For Manual Valves:

Manual valves are much more forgiving than automatic valves. You don’t need to worry about having enough pressure to allow the valve to close by itself, it uses “elbow grease” to power it! However, you still need to find out what the pressure loss through the valve will be so you can enter it in your Pressure Loss Table. As with the automatic valves, you use a chart provided by the manufacturer for this. Follow the same procedure given above for automatic valves. Unfortunately, pressure loss data for manual valves can be hard to find as many manufacturers don’t provide it. As a general rule, allow 2 PSI pressure loss for a globe or angle type manual control valve, 5 PSI if it is an anti-siphon valve. Manual irrigation control valves should be of the “angle” or “globe” type with replaceable rubber seats. Never use a gate valve as a control valve. Gate valves are not made to be regularly opened and shut. Many gate valves will start leaking after as little as 10 uses!

Want to use a manual valve now but change to an automatic valve later? No problem. Simply design for the automatic valve, but use the manual one instead. Then you can replace it later when you want to automate the system. Another way to do this is to install the automatic valve and simply operate it manually using the manual on/off lever. If you do this, then later you just install a controller as well as wires between the controller and the valves and you have an automatic control system.


This article is part of the Sprinkler Irrigation Design Tutorial
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How to Use Pressure and Flow Switches with Irrigation Controls

Almost any major maintenance problem in an irrigation system will cause a unusual pressure level or flow level in your irrigation system.  Therefore pressure and/or flow monitoring is a good way to detect problems.  Most of the time the response to a abnormal pressure or flow level would be to shut down the system, or possibly to shut down the current valve zone  and try another one.  Irrigation systems are typically shut down using what is called a master valve.  A master valve is a single valve located at the water source that can shut off all the flow of water into the irrigation system.  For more details see my article on master valves. On systems with a pump you will probably want to shut off the pump.  Sometimes, as with booster pumps, you will need to both shut down the pump and close a master valve.

So what problems might an abnormal pressure or flow indicate? A very low pressure may indicate that perhaps the pump is broken (if you have a pump), an intake screen is clogged, a filter is dirty, a valve failed to open, or a pipe has broken.  Abnormally high pressure could be the result of  a valve not opening when it should, a dirty filter (if the pressure is measured upstream of the filter rather than downstream) or some obstruction in the pipes.  Low flow could indicate a valve failed to open, a filter is dirty, or that a pump isn’t working as it should.  High flow could indicate a broken pipe, a broken sprinkler, or a valve that is stuck open.   In most cases monitoring either flow or pressure is sufficient as opposed to monitoring both.

 

How to Monitor Your Irrigation System

There are a number of different ways to detect and respond to abnormal pressure or flows.  Following are a few or these.  If you would like to suggest other methods, please contact me.  I realize this is not an exhaustive list.

Use a Smart Irrigation Controller that has a Sensor Input and Response Feature:
This is probably the easiest way to add pressure detection and response.   It is also what I consider to be the preferred method, as it is reliable and gives you the most control.  Some high-end irrigation controllers can use an electronic sensor hooked up to the mainline pipe to monitor the water in the irrigation system. Some of these controllers use flow sensors, some use pressure sensors, some can use both types.   These controllers with advanced features are typically sold as Smart Controllers and are expensive compared to ones typically found on a residential irrigation system.  Prices for these controllers typically start around $300.00 and go up into the thousands for ones that handle dozens of stations.  But then you get a lot more with them too.  They are sold through professional irrigation supply stores, both online and locally.

WARNING: Be sure the controller will do exactly what you want BEFORE you purchase it!  Not all controllers marketed as “Smart Controllers” have these sensor input features, many only work with specific types or even models of sensors, and some controllers may not provide the response options you want or need.  You need to research the controller carefully.  Don’t rely on a simple check list of features!  “Sensor input” can mean almost anything, you need details!  I have seen controller feature lists where the unit sounded fantastic and ultra flexible, only to discover after closer examination that the actual response features don’t do what I need or want.   Read the actual owner’s manual (most controller manufacturer’s have them available on their websites) to see what the true capability of the controller is.  Read the sections of the manual on how to hook up the sensor, then there will also be a separate section on how to program the sensor you should look through.  Some controllers allow for time delayed responses, some don’t.  If you have a pump you will almost always need a time delay feature to bypass the sensor when the pump is starting up.  Even those controllers that do allow you to add delay times may not allow as much or little time as you need.  It is critical that you do as much research as possible before you go to the expense and effort of purchasing, installing and programming the controller.

For example, I have a Rainmaster Eagle Smart Controller on my own irrigation system, as well as using it on the majority of the commercial systems I design.  This particular Smart Controller has flow sensing capabilities, but it does not have built-in pressure sensing capability.  It does have a delayed response allowing delays of 1-6 minutes, but only in one minute intervals.  It will also allow the use of one additional simple on/off type sensor (most controllers have a circuit for this type of very simple sensors.  A simple rain switch is an example of this type of sensor.)    It has an audible “chirp” alarm that alerts you that a sensor response has been activated.  While this particular controller meets my needs, it certainly will not meet everyone’s.  Almost every major irrigation company makes a Smart Controller, and each has different features and capabilities.  Be sure you are using up-to-date resources when checking out models.  Smart Controller models are introduced each year, and often the capabilities of existing models change from year to year, so it is hard to keep up with them.

When using a controller with a pressure and/or flow sensor you start by installing the actual sensor on  the mainline pipe.  The method varies with the brand and model of sensor, most are pretty easily installed.  The sensor is wired to a special terminal on the irrigation controller.  Typically the wire used must be a special shielded communications cable, rather than standard irrigation valve wire.  Consider installing communications cable in PVC conduit to protect it, as it is very sensitive to even the smallest nicks from shovels, animals digging it up, or rodents chewing on it.  Most pressure sensors work by sending a reading of the current pressure to the controller every few seconds.  A typical flow sensor has a small paddle that turns as the water flows through the pipe.  Flow sensors normally send a signal based on the amount of flow, for example they might send a signal each time 5 gallons of water has flowed past the sensor.  The controller then interprets that data from the sensor and responds.   In most cases you will pre-decide what the response will be when you set up the controller.  For example; if you have a system with a pump, you could program the controller to shut down the irrigation system if the pressure was below 10 PSI for more then 2 minutes during the set irrigation period.  The 2 minute qualifier (delay) for shut down would allow the pump time to pressurize the system during start up and also avoid “false alarms” caused by brief dips in pressure.

Using a Simple Pressure Switch with a Pump Operated System:
This method is for those with pumps.  What I am describing here is for emergency shut off only.  I’m assuming you already have something set up to turn on or off the pump during normal irrigation operation.  That might be a standard pressure tank with a pressure switch to control it.  Or you may be using the pump start feature on the irrigation controller to actually start and stop the pump using a 120v relay.  The new pressure switch we are talking installing in this case is used only to detect pressures that indicate a problem and turn off the pump.  So if all is hooked up properly, in the event of blockage or no water going into the irrigation system the pressure will drop and the new pressure switch will shut the pump off.

This method requires that your irrigation system is leak free and can hold pressure for days between irrigations.  If the system is not leak free see #4 below.

1. Make sure you have a really good quality spring-loaded check valve on the irrigation mainline pipe.  The check valve goes someplace after the pump, but before the pressure switch.  A good quality check valve is needed to keep the water from leaking backwards out of the system through the pump.  Typically the self-priming feature of the pump is not good enough by itself to do this, you need a separate check valve.

2. You will need to use a pressure switch that works backwards from normal ones used for household water systems, since you want the switch to shut off the pump at low pressure (standard switches used on household water systems turn on the pump at low pressure.)  Some switches can be wired to work either way, others can’t.  Keep in mind that the low end on many common pressure switches in around 25-30 PSI.  That might be a bit higher than you want for a low end shut off, especially if your system will be operating at less than 45 PSI.  You don’t want accidental “false” shut offs since the only way to get the system back on will be to manually start the pump and hold it on until the pressure is back above the shut-off level.

3. There a problem to be dealt with.  The problem is that valves close slowly, taking as much as a minute or two to close after the controller tells them to.  At the end of the last irrigation cycle a typical controller closes the last valve and immediately shuts off the pump.  But it takes the valve several seconds up to a minute or two to actually close.  During this closing period the system will depressurize.  With no pressure in the system the pump will not restart for the next irrigation cycle, because the low pressure shut-off switch is detecting low pressure and shutting off the power to the pump.  There are two ways to deal with this.

A. You can fool the controller into keeping the pump running after the last valve circuit has finished watering.  Your controller needs to have the capacity for one extra valve on it to do this, so if you have 10 valves you will need a controller with 11 stations.  The last station on your controller needs to not have a valve attached to it.  Program 1 minute of time on that last station.  Now the controller thinks it is operating one last valve, so it keeps the pump running.   That will keep the system pressurized while the final valve closes.  If one minute is not enough time for the final valve to close then add another minute of run time to that last empty station.

B. Some controllers have a built in delay feature that keeps the pump running after the last valve closes.  This feature keeps the pump start circuit energized, which keeps the pump running for a minute or two after the last valve is signaled to close.  This gives the valve time to close before the pump is shut off.   Some less expensive controllers have this feature.  But typically only high-end controllers have this feature, so this method isn’t very practical.  If you are going to buy an expensive controller you might as well forget about using a pressure switch and use a Smart Controller and a sensor to shut the system down, as described in the first section of this article.

4. Often a small leak will cause the system to depressurize between irrigation runs.  This can be a major problem.  The pump will not start if the pressure is low, the low pressure switch is going to shut off the power to it.

If the leak is very small you can install a pressure tank, just like on a typical house water system.  Assuming a small leak, the tank keeps the system pressurized.  But that only works with a very small leak and it can take a huge pressure tank to supply enough water to keep the system pressurized.   If your system has a larger leak you will need to find and repair the leak.  If you can’t get the system leak free, you will need to take a different approach, as described below.

You can use a timer to over-ride the low pressure switch, and allow the system to start even with no pressure.  You will need a “Time Delay Relay”.  The time delay relay needs to be the type that allows the power to flow when energized, then shuts it off after a minute or two of delay.  It needs to have an automatic reset.  You then install the relay on a bypass wire around the low pressure switch.  That way the pump can start even when the pressure switch is “off” due to low pressure.  You will need to work with someone knowledgeable when ordering the time delay relay to be sure you get the correct relay, as they make many different kinds.

Using a Pump Controller with a Sensor:
This is essentially the same method as the Smart Controller method I described earlier.  Only the “smarts” are in the pump controller rather than in the irrigation controller.  Some of the newer digital pump controllers (don’t get confused here, we’re talking about a separate pump controller, not the sprinkler controller) are programmable, they are simply a small computer that operates a relay that starts and stops the pump.  You hook them up to a pressure sensor, also to the irrigation controller, and to any other sensor you want (wind, rain, temperature, light, flow, you name it.)  Then you can program them to do just about anything using that information input.  They can turn off the pump if a low pressure occurs for more than x number of seconds, turn off the pump if a high pressure occurs for x number of seconds, turn on the pump at a given time of day, etc.  Pretty much any input you want can cause the pump to turn on or off.  The capability depends on the brand and model of the pump controller. The downside is it takes electronics know-how to set the thing up and someone tech savvy to program it.  Typically you hook up a laptop to the pump controller to program in the logic, then once it is programmed it runs by itself.  The laptop just gives you an interface that is easier to work with.  I really can’t give you much more details beyond that, this type of pump control is beyond my expertise, I just have seen pump system experts use them to do amazing things.