How Do Sprinkler Valves Work? Rain Bird Irrigation

[@sarahpawlak1859]

Wow. Who knew I'd be left amazed watching a video about a sprinkler valve. Thanks.

[@archerpiperii2690]

Whoever put this together....thank you!!

[@crunchycrispybacon]

Whomever invented that valve…Thank you!

[@thisherewalnut8139]

Who so ever comments after this comment.... Thank you!

[@ronwolfarth9832]

You're welcome.

[@angelvasquez5066]

Wym?? Rain bird made it

[@Mark1Mach2]

Such good explanation. It's easy how a complicated system works with a small visual diagram. Thank you.

[@jeremymitchell5998]

BOT COMMENT SYSTEMS ARE GARBAGE

[@tjgallo]

Extremely impressive and informational. Thank you for sharing this!!

[@jeremymitchell5998]

Yeah okay their system is garbage and instructions might as well be written in Japanese if they got the instructions you need like spring start up they didn't give me one thing on instructions on how to start I seen five different videos of people turning it on five different ways and none are working my system is 1 yr old GARBAGE

[@RainBirdCorporation]

Hi Jeremy, if you have any questios, we'd be happy to try and answer them!

[@ToddOja]

Love my Rainbird system. Did it all myself.

[@impostor51]

Rainbird is my go to brand for control panel installs or valve replacements

[@billjuss5331]

THANK YOU RAIN BIRD, EXCELLENT KZbin VIDEO!!! Easy to Understand!!!

[@utubmbr]

Great video and explanation. Simple to understand. Thank you!!

[@Zaru7t10]

Currently working on a golf course with lots of rainbird stuff so this is extremly helpful as I am fairly new with all this.

[@mikeharmon8733]

Sorry, but without training or a lot of experience you will be quickly overwhelmed. You are on the right track though, with educating yourself.

[@noeeon9910]

Really? A Golf Course? Your playing in the big leagues and your new to this? Who are you rubbing elbows with?

[@Zaru7t10]

@@noeeon9910 What's big league? Golf course or working with rainbird stuff? Irrigation is fairly simple imo. Now the comment is 3 years old and in retrospect it worked out well. I did my job well. No longer working with golf but thats for a whole different reason! :)

[@noeeon9910]

@@Zaru7t10 Golf Courses is big leagues... Not working with rainbird. And yes irrigation is fairly simple.... In theory. I'm sure you " fixed" the issue. But doubt you did it right.

[@Zaru7t10]

@@noeeon9910 My boss at the time had worked on golfcourses some 20 years and he never complained about my work with our irrigation system. But yes, if you compare that course I worked on with the big league courses in US and whatnot, I wouldnt stand a chance ofc.

[@TheResidentSkeptic]

This is a great explanation of valve operation, however one thing was omitted: the spring above the diaphragm. If the valve is closed simply by the water pressure above the diaphragm, then why is there a spring there? And why does the valve fail to close if the spring is removed? That spring seems important...

[@valquiriasilva8721]

rain bird lá to the beach eu to do a lot of homework homework and then homework and homework to do and so we will be doing

[@RedHaloManiac95]

Yep the spring is what allows it to overcome the inlet pressure

[@kg4lod]

@@RedHaloManiac95 Not quite. The inlet pressure and the bonnet chamber pressure will equalize so there is no pressure to overcome, the problem is that the bonnet will simply float somewhere between open and closed. To ensure it closes, you need a small additional force to make it "sink" back to the bottom and seal closed. Essentially, the spring guarantees that the inlet + spring pressure is always greater than the backflow outlet pressure -- ensuring that the valve closes and stays closed.

[@RedHaloManiac95]

@@kg4lod wow you said exactly what I did except with 10x the words! You literally said “the spring is what allows it to overcome the inlet pressure” yes if there was no spring it could not overcome anything it needs more pressure than the inlet to close hence “overcome inlet pressure” Jesus Christ

[@benjaminreinhardt259]

Good explanation and clever valve design. I have no need for this type of valve or an irrigation system, but still enjoyed the video.

[@dalesmth1]

I used to work on the industrial version of these. Largest one I worked on was 36 inches.

[@FredHerrman]

That’s cool. I thought that it was a motor that turned the valve on and off. Now I have to look up solenoid.

[@The09creeper]

Fred Herrman a solenoid has a magnet inside it moving a metal rod

[@nspinicelli]

Good god! So advanced for such a rugged piece of equipment! QUESTION: if I pressurized one zone with compressed air through where a pop-up would go, would the air pressure be able to escape back through a closed solenoid? I'm having a problem during winterization where my air pressure is escaping through an an automatic drain, located 4 feet underground.

[@mariobeans]

yes you can blow air through a pop up head. then open up your other zones one at a time either manually or through your clock.

[@noeeon9910]

Curious, why is there an automatic drain 4 feet underground? Anyway to answer your question, no air will not escape through a closed solenoid.

[@albertanasoul]

Great video, thanks for posting it. I have installed one underneath my camper van to drain the grey water tank. It gets below zero where I live in the winter time, so I have completely wrapped the tank, hose and solenoid with insulation. Is there anything wrong with keeping the solenoid completely wrapped in insulation and does the manual knob move when the valve is electrically opened/closed? I forgot to check before I did the installation...

[@RainBirdCorporation]

Hi, The solenoid handle does not make any movement when receives voltage. It is only a tool to know what the current position of the solenoid is. Every time that system is winterized. The best option is to leave the valves opened. That is how the system gets pressurized manually and takes the remaining water out.

[@nabysrojas]

Great video, thank you. I would like to know how to adjust the PILOT FLOW FILTER. I know it is done by turning the screw, I mean how tight should I do it

[@mariobeans]

you dont adjust it. I think you're referring to the bleeder screw right above. unscrew it a bit and it opens up the diaphragm. Basically just a way to turn your valves on manually. You can do the same with the solenoid.

[@addleyscanada]

Bleeder screws main function is to help flush debris, it also turns on the valve by chance

[@GeorgeGeorge-xj2bc]

The water flow from the hole when electromagnet lifts is acting as a lever to lifts the diaphragm because there is a small hole in the diaphragm that fills the chamber but in higher water flow lifts the diaphragm.When the water flow stops from the electromagnet hole the water pressure then pressures back the diaphragm to close.Similar to the electric relay action.

[@swf4iubrh4s]

Thanks for putting together the animation. A.H.W.

[@DefundTheFringes]

Good soundtrack.

[@fred4687]

Thank you, good explanation ...... now I need to identify and excavate my misbehaving valve to see why it doesn't want to close fully 😀

[@coltwinchester6124]

Most likely debris in the valve.

[@fred4687]

@@coltwinchester6124 That was my guess as well when I went hunting for it. After a good clean though it still misbehaved, I suspected a worn diaphragm and replaced the top. All good since. That was months ago and as that retic line was a bit overgrown, and I hadn't drawn a detailed enough diagram for it, I started digging for the pipe and joins etc - goes under the driveway and branches to a couple of additional areas. I've still got to finish off that task, then put some rocks back. Something else always comes along that is a higher priority when you're a weekend DIY-er 🙂

[@coltwinchester6124]

@@fred4687 40 year experience here. You are on the right track, 🤔

[@richardcroxton760]

Good little video, well done.

[@zaloalvarez6947]

So you need a valve to have enough pressure to the sprinkler system?

[@jackhays2645]

If one has a 3/4" inlet will it be a "full flow" 3/4" going out?...OR does this valve cause one to lose water volume as opposed to a full flow ball valve?

[@noeeon9910]

what your asking: Is there is loss of flow because of the mechanical interworkings of an elec valve vs a manual ball valve? the answer is yes. There is a small loss of flow due to friction loss, this happens through out the whole system. there are charts for these calculations. Determine your GPM or ( Flow ) and find the friction loss for a 3/4" valve..

[@elizabeth84266]

So how do I turn my sprinklers on when the control box is broken/can’t get power?!?! Whenever I turn the bulb thing… water seeps out but it doesn’t push through my irrigation line like my other irrigation box will let me do…. Any ideas?!?! I’m desperate….

[@joysun364]

Great Video! Thank you!

[@heroknaderi]

This video is very interesting 😮😀😀😁

[@Level-333]

Can lowering flow control help stop water hammering

[@direx285]

I have a new one i mounted vertically that doesn't seem to work as it always allows water to flow. Does it need mounting horizontally?

[@noeeon9910]

No, you valve is bypassing. Change your valve.

[@everythinghomerepair1747]

Great explanation!

[@GeorgeGeorge-xj2bc]

My question is,can these type of valves be used as a general electrovalves or intended only for garden use?I plan to make a electronic level sensor for a water tank and need an electrovalve,so can i use an irrigation valve?The water tank is upstairs on a loft inside the house.

[@addleyscanada]

Few things you'll need to keep in mind. You need sufficient pressure upstream for the valve to function correctly, then you need something that will trigger the solenoid at 24vAC.

[@GeorgeGeorge-xj2bc]

@@addleyscanada Finally i use a washing machine valve since the amount water that flow is small and also has better sealant and very little weight of few grams and fitted directly to the tube.The irrigation valve of 1 inch when filled with water weights about 1 kgr.

[@garywiens8625]

@@addleyscanada actually you don't even need 24vAC to actuate it. I have used as low as 8vDC to actuate it before.

[@sunitbansal]

Hi, So, does that mean there can not be a backflow from the outlet to inlet when the solenoid closes. I have the inline values in my front and back yard, and I do not know if need a backflow preventer or not. Please let me know urgently

[@mariobeans]

you still need a backflow if you're on culinary.

[@sunitbansal]

@@mariobeans Thanks. I replaced all my inline valves with anti-siphon valves. But now, when the sprinklers turn off a see a gush of water comes out. Is that OK

[@Player-mi9hf]

Will this valve help reduce water pressure for a drip irrigation system? The water pressure in the greenhouse I’m working is very high and the drippers blow up.

[@RainBirdCorporation]

For drip irrigation systems, you'll need a low flow valve or control zone kit. Here are some options: store.rainbird.com/nsearch/?q=low+flow+valve

[@SmartIrrigation1]

Good Job, very informative.

[@MS-ib8xu]

Thank you! Very helpful!

[@jimcaulk6225]

I have two valves that stay open, powered or not, is that bad solenoids?

[@ruenjou]

Very informative

[@marvisirrigation4796]

Will the valve work without any water pressure? What is the minimum amount of pressure to make the valve work?

[@noeeon9910]

I hope you dont own an irrigation company.

[@marvisirrigation4796]

@@noeeon9910 I do and have been in the industry of close to 20 years. I posed the question to settle and argument with a new "Irrigation Contractor" who was advising people to simply let the controller run through a cycle to prevent freezing in the system. Very misguided advice in my opinion. If you would care to weigh in on the subject I would be interested in your opinion.

[@noeeon9910]

@@marvisirrigation4796 misguided advise? You are a pleasant fellow. Theres too many variables for me to give you advise on that matter including backflow device, region, and design in order to winterize properly. With that said however that new irrigation contractor is very misinformed.

[@RitaMarquesPinto-i7j]

I have a problem as my valve seat does not seem to stop the water flowing when the tap is on. The sprinklers will just turn on automatically, what can I do? In my other systems I can turn the valve seat on manually to turn the sprinklers on but this one does not seem to do the same.

[@venkatgudipoovu3132]

My Rainbird valve doesn’t turn on manually turning the solenoid, the sprinklers don’t pop up, just low flow. What should I do? Thanks in advance

[@noeeon9910]

Replace it, diaphrams probably stuck half closed. Or just completely deteriorated.

[@5280-life]

check the water pressure also.

[@hhezzah]

What if the valve fails to shut off due to the diaphragm getting a hole or anything else . Is there a way to turn off the water manually?

[@noeeon9910]

No.. if the valve doesnt shut off you will have to go back to the source and shut it off there.

[@ronwolfarth6446]

This video depicts the operation of a reverse flow valve (as noted in the narrative). If a reverse flow valve gets a hole in the diaphragm, the valve will close. That higher flow of water through the diaphragm will overwhelm the solenoid dump port allowing water pressure to build on the top side of the diaphragm. That pushes the diaphragm closed. So, if a valve won't open, one possible cause is a hole in the diaphragm.

[@joeystephens1600]

Im trying to diagnose why one of my circuits wont turn on, it just has a light trickle when turned on. I opened the bonnet to find the pilot flow filter broken and laying in the bottom of the valve body. it seems like that is a very likely cause of my problem. Ill be picking up a rebuild kit tomorrow to see if this fixes it. Ironically this failure happened at the exact same time I tried testing a new sprinkler head on the same circuit for the first time (it worked fine earlier in the day with the old sprinkler head installed), causing me to think there was an issue with the new sprinkler. We will see though. if not, I'm calling a professional haha

[@mrmastertj89]

Having same issue. Did you figure out what the problem was?

[@joeystephens3208]

@@mrmastertj89 yes, I replaced the diaphragm with a kit from home Depot and it fixed everything. Working perfectly now

[@robertt4313]

I need to know why I have more water and pressure if I manually turn on my valve vs when my controller electronically turns it on?

[@robertt4313]

Cmon no body?

[@Lesscoelectronics]

now I know!

[@wayneguy6043]

What does the valve seat screw do

[@rajusondh]

genius design..!!

[@Derail07]

You will never see a day laborer install the system that clean

[@thegfxmech5475]

This animation allowed me to finally figure out what that little screw was for. I had a station that had power going to it but the sprinklers wouldn't activate. After turning the screw counter clockwise, some water spewed out of it and the sprinklers for that station started working again. If I tighten the small screw once the sprinklers get going, about 30 seconds later they'll shut off. Is this normal? What gives?

[@noeeon9910]

This one rainbird does answer.... way to go rainbird!

[@thegfxmech5475]

Yup it was the solenoid that was bad

[@adslf874yti3q7u4hf83]

I know this is 4 years later, but that screw "bleeds" the water from the top of the diaphragm thus lowering its water pressure and allowing the valve to open. However the solenoid is still closed, so as soon as you tighten the screw again the pressure begins to build in the top of the diaphragm and shuts the valve. I had exactly the same question as you, so it's not uncommon. These things don't exactly come with instruction manuals.

[@larryenglish8900]

do these work for any position of the valve?

[@jimmys.8062]

I know the valves are supposed to work inlet to outlet with the arrow direction.. but what happens IF it is installed backwards? ie does it still work correctly? (And i'm pretty sure i did it backwards. Because if i turn it 'ON' the station shuts off, and the station started running immediately after replacement.)

[@elguapo6731]

Jimmy Scott same ? Any update ?

[@noeeon9910]

I've installed probably a few... yeah I'd say 3 in my lifetime backwards and when I went to kick them on.... nothing happened. After closer inspection I realized I was moving so fast I put it on backwards

[@Max14163]

So it's like a transistor, where a little current controls a much bigger current!

[@RichardKinch]

Yes, that's an important principle, like a bipolar junction transistor. It takes a lot of mechanical power to open a big valve. A tiny flow from a small solenoid valve, that doesn't take much power to operate, leverages the power of the water supply to actuate the big passage.

[@mohanr1947]

Impressive

[@effortsibanda1130]

Can these valves be turned on manually if there is system failure on the program or if it has gone damaged

[@florra]

Yes

[@treygrant5030]

Yes turn the solenoid

[@timavery99]

Turn solenoid counter clockwise (loosening) about 1/4turn. Or some valves have a small plastic manual control next to solenoid that raises plunger when flipped.

[@mariobeans]

I prefer unscrewing the bleeder screw

[@Adnaneee]

Nice

[@RemoRomano]

Should the solenoid be in OFF position normally? When I turn the solenoid in ON position (manually) my Orbit station cannot stop the water from flowing even if programmed to be off. But if I close the solenoid (manually) water doesn't run even if the programmer is telling it to. I'm thinking it could be a fault in the Orbit station. Any help would be appreciated. Thanks.

[@mhal5811]

I have the same issue. Did you figure it out?

[@supre_memighty2283]

Check the 2 wire going to solenoid . Orbit station terminal if you get 24 volt when you turn it On . If you get output . Then check the end of that wire that connect to Solenoid if connected the one with waterproof wire connector.

[@sheckyfeinstein]

Thanks.

[@shred46]

That was great!

[@kanguro354]

Hey l have 6 stations but number 1 don’t shut off stays on all time you know what is the problem??? Maybe selenoid valve ????

[@jdwang3930]

I had this problem with on of my stations. To prove it is not a problem with the solenoid, I took a solenoid from another station and used in the troubled station. It did not make a difference. At that moment, I was pretty certain the problem is with the port, which allows water from the inlet to get into the top of the diaphragm, blocked by debris. Since the water from the inlet port does not flow to the top of the diaphragm and thus no water pressure is there to hold the diaphragm down to prevent water from the flowing from the inlet port to the outlet port . The filter of this port can't be cleaned out easily and the diaphragm is 15 years old; thus I simply replaced it. It is about $5 in Lowes and Home Depot.

[@buscador2007]

I have found some problems with the bonnet, sometimes they crack where the selenoid dump port is, causing the valve to stay open all the time, I have seen that problem with Hunter and Rain Bird valves, a hair thin crack barely noticeable.

[@marvisirrigation4796]

Most likely debris in the inflow.

[@shakeandbaked1]

buscador2007 that can happen to any plastic irrigation valve. Some older fiber filled valves from rainbird in the peb series are notorious for this also people can cause it by over tightening the male adapter. In my experience a lot of home gamers like to tighten things to the nut.

[@larryl8676]

What is the name of a black screw above a Pilot Flow Filter? What is it for?

[@officerkrupke4966]

If the valve isnt working, the first thing to try is to flush out any debris that may be interfering with its operation. You do this by opening the Bleed screw about one turn. Sprinkler zone will turn on as you do this, so be aware.

[@averageguy1261]

I don't get it, but I believe you.

[@falloncushion304]

Dumb question but the does the solenoid have to be tightened

[@mariobeans]

only hand tightened.

[@varunchandrappa5123]

Is there any video or document I can refer to know how to connect solenoid to rainbird controller (LXME)

[@noeeon9910]

Solenoid to raibird controller? I can help but I need more details.

[@5280-life]

Just for simplicity, run pair of wires to the solenoid. One wire from the solenoid to the common on controller, the other wire to the zone on the controller. That's it.

[@halimoussama862]

what if the valve keep receiving water for a long period, there is some risk for it to explode ?

[@noeeon9910]

Not if it is installed within the manufacturer's pressure ratings.

[@harryl7946]

I watched twice and still do not understand 😢 exactly how the water pressure in the top over powers the flow from the supply line.

[@agilis1]

Water within the irrigation system naturally flows into the valve. This water is guided into the solenoid and the bonnet chamber, where this water presses down on the diaphragm preventing water flow. A plunger, controlled by the solenoid, sits in a relaxed position which seals the dump port. When power is applied to the solenoid, the plunger moves upwards. The water from the bonnet chamber and around the solenoid to flow into the outlet of the valve via the inlet. The water exiting the inlet is at a much higher pressure which overpowers the low pressure water pressing down on the diaphragm causing the diaphragm to move upwards allowing the valve to open.

[@exactspace]

I just watched this high

[@graceding918]

exactspace me too and I have no idea what he’s talking about haha

[@exactspace]

So fun

[@typ8723]

Anne I'm drunjj

[@lllblisslll]

I’m confused now though. When I blow out my lines prior to the winter, I pressurize the system & turn that smaller knob counter clockwise a half turn to get the air to flow through that particular valve/zone which then blows that zone out. Not sure how that works by looking at this animation as that little valve doesn’t seem to be doing anything.

[@PhuryousOne]

The "smaller knob" is a bleeder valve. It opens the valve manually by releasing the pressure at the top of the diaphragm that holds the valve down, similar to the dump chamber underneath the solenoid.

[@lllblisslll]

@@PhuryousOne ahh interesting, thank you!

[@oktayyilmaz5476]

Can 24V AC selenoid vlave work on 24V DC power?

[@RichardKinch]

No, not generally. The solenoid's wire coil has more impedance to AC than DC. If you apply DC, too much current flows, and the coil overheats and fails. Same thing applies to contactors that actuate on 24VAC. The Rain Bird TBOS solenoids operate on 9VDC, and are drop-in replacements for the original 24VAC solenoids, so you could try that if you need to convert a Rain Bird solenoid valve to DC instead of AC. Furthermore, the TBOS design is a latching solenoid, so you only apply a voltage briefly to turn it on or off. This how the Rain Bird valves are converted to run on battery-powered controllers that can't afford to power solenoids continuously or with AC. The 24VAC controls are obsolete, dating back to when controllers comprised only transformers and crude switches.

[@lntrlp4936]

Way better product than Toro offers.

[@MakeItMike]

whats the port for at the top right?

[@mariobeans]

bleeder screw. you use to to open valve manually. you can do the same by loosening the solenoid a tad

[@xtrememotoroads]

what if there is no spring attached with the diaphragm?

[@securus777]

Likely then you're sprinkler will always either on or off. Pretty sure always on.

[@xtrememotoroads]

@@securus777 i have seen many 2 way valves with integrated solenoid have spring attached with the diaphragm and some other type 2 way valves dont need springs. can you explain the advantage of not having springs in the diaphragm. in dorot make 2 way valves there is no spring required in the diaphragm.

[@securus777]

@@xtrememotoroads Nope, sorry. Just a homeowner with a super basic system I'm trying to figure out on my own. :D

[@noeeon9910]

@@xtrememotoroads I can answer that question, I just need to know what other type of 2 way valves without springs you are talking about, like ball valves?

[@RichardKinch]

@@xtrememotoroads In some designs the rubber elasticity of the diaphragm itself provides the spring component, to save cost. But having a metal spring makes the operation more responsive and reliable, and gains the adjustable flow control stem feature. The spring stays the same over a lifetime, but a rubber part gets stiffer and goes "out of tune", so only the metal spring will last.

[@garymayfield3279]

Looks more like a Hunter vale ,than a Rainbird pvg

[@vijay1968jadhav]

how can I buy

[@pacz8114]

(Very informative. One question: what does all that intrusive music have to do with learning how an irrigation valves works?)

[@intrpolfan1]

My sprinklers only turn on manually by turning the screw. Why is this?? Turning the solonoid does nothing.

[@jessasdad]

Your solenoid "piston" could be stuck. Solenoids are super easy to replace.

[@5280-life]

replace with new matching solenoid

[@pedromontejoperez8427]

Numero para localizar al proevedor

[@adudenamedjoe13]

This was actually really fucking cool. Here I am. 29 years old, two kids sleeping, wife in bed, and I’m sitting on the toilet, post shit, watching videos about how my sprinkler valve works. I guess this is what adulting really is

[@johnkosheluk1041]

I know how thay work i do sprinklers sys but you forgot to say what the spring does it holds the dighram closed

[@deankay4434]

+john Kosheluk The center spring on top of the rubber diaphragm does several things. First, it helps the valve seal a little quicker when the solenoid is de-energized as water under pressure has to flow back on top, thru the tiny bleed hole, to create a pressure difference. At this point, not only does it help timing as the next zone opens, but secondly also helps in alignment of the rubber valve seat to close. With the Toro brand, the spring is on the solenoids tube which acts as a guide, but still aids in quicker closing of that zone & its water flow. Try it sometime without the spring, then note how much longer it takes the water to shut off. The next zone opens, with a slight delay, but having two zones open, creates a drop in supply pressure. If that occurs, the zone timing will be off and the next valve to open will take longer to unseat the rubber diaphragm. It is like an automatic transmission valve upshift. A valve allowing hydraulic fluid to hold the component for 2nd gear operation, has to release quicker that the valve that allows for 3rd gear to starts holding. Otherwise, you have some holding of two gears at the same time, which is bad. Hope that helps.

[@typ8723]

@@deankay4434 you guy you

[@chrisp.6056]

why do you have to have back up music?? it makes it hard to hear

[@coltwinchester6124]

So many so called Irrigation repair specialists don't know this. So they don't know how to repair a valve, so they just replace them. Thus costing their customers more money.

[@EPTRotorsports]

Valves are pretty cheap

[@modernirrigationsystems7337]

Let me do some publicity with you

[@c31979839]

You want them to pay you?

[@jimlarsen6782]

Its all wrong. The water comes in the bottom hole covered by the diaphragm and goes out the side. This all occurs UNDER the diaphragm. The top is for the tiny dribbles that actuate the valve!

[@Ditmanppi]

So you’re saying Rain Bird doesn’t know how their own sprinkler valves operate? That they designed? This is the legit Rain Bird company KZbin. I kind of trust their word over yours no offense.

[@jimlarsen6782]

Im sayin the illustrator or the explainer is all wet. The main water flow never passes above the diaphragm, and thats a fact.

[@johnrausch1555]

Ñ

[@valquiriasilva8721]

Beluga.

[@jeremymitchell5998]

Rainbird systems are garbage this whole thing is a propaganda

[@TheDylan6908]

Far too much info😮

[@sunitbansal]

Hi, So, does that mean there can not be a backflow from the outlet to inlet when the solenoid closes. I have the inline values in my front and back yard, and I do not know if need a backflow preventer or not. Please let me know urgently

[@rockwellmath]

Normally you do need a back flow preventer, for the times when the city water is shut down. At that time, there might not be enough pressure to keep the diaphragm closed, and water from the outlet side of the valve can flow backwards through the valve and into the city water supply. And theoretically that water can contain contaminants - fertilizer, E coli, etc. You should check with your city building department to see if a backflow preventer is required.

[@sunitbansal]

@@rockwellmath Thanks. How serious is it. My landscaping contractor just installed inline valves in both front and back yard. Also, it is causing a loud thump in the plumbing house when the sprinkler valve closes ( I assume that due to the water pressure hitting the valve and bouncing back). Do you recommend getting a back flow preventer or just replacing the existing system with anti-siphon levels

[@thatguythatdoesstuff7448]

@@sunitbansal For anyone reading this and wondering, you should ALWAYS install a vacuum breaker/backflow preventer. Any modern municipality requires it by code. Also, what you described is called water hammer and I can't imagine that is being caused by a sprinkler valve. They close too slowly to cause water hammer, unless you have crazy high water pressure at your house. You might have a master valve before the actual sprinkler valves. Could be the cause? Either way, homes with copper piping should have water hammer arresters installed, if the home doesn't already have them.

[@5280-life]

You will need separate backflow preventer. These valves (rubber diaphragm and contaminated water) will fail.