# Starting Up Sprinkler System For The Season



## jaygrizzle (Jun 6, 2018)

Looking for the steps to take to get the sprinkler system set up. I had the system winterized by professionals last fall and had the back flow tested a couple weeks ago. I didn't have them activate the system because it was an extra $100 and at that time we were planning on selling our house.

However we ended up deciding on building a new home so now I'll need the system this summer. Here's what the current set up looks like:









What steps should I take? I've worked with the system that last few years so I know what to do once it's ready, but haven't turned it on for the season before. Looks pretty simple but just looking for some confirmation that what I think is the correct sequence.

Thanks


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## jaygrizzle (Jun 6, 2018)

Pictures came in to the post in a funky order. Top and bottom pictures are from the outside. Third picture is from the basement which leads to the outside.


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## g-man (Jun 15, 2017)

Trigger a zone to run for 30min or so.

Did you turn the yellow valve in the basement? If yes then blue and then slowly the green valve.

If not, there should be another valve in the basement. It will be that valve first, then the blue and then slowly the green.

Turn off the zone, turn off the green, then switch to another zone and repeat.


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## jaygrizzle (Jun 6, 2018)

Yes the guy from the sprinkler company turned the yellow valve in the basement parallel to the pipe which from my understanding got the water flowing to the outside unit which was needed to do the back flow test.

I'm assuming I would slowly turn the green valve parallel to the pipe? In what position should I leave the green valve once I've completed running each zone for 30 min?

Thanks for the help g-man!


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## g-man (Jun 15, 2017)

Ok, so that explains the yellow valve.

The idea of the 30min is just to have the valve open. The time is not important. All we are trying to do is not to have a rush of water going thru the empty pipes. By opening the green one slowing you will start to fill them up. Once they are full and you see all of your heads flowing, you can turn off the zone and move to the next.


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## hsvtoolfool (Jul 23, 2018)

@g-man, as I understand how solenoid irrigation valves operate, the startup order really doesn't matter. There's no advantage to turning on a zone, then opening the water cutoffs. The exact same thing happens if you turn on the water first, then turn on each zone second.

Solenoid irrigation valves don't operate without line pressure. In other words, they use the line pressure to open the valve. The electric solenoid only opens a small bypass orfice, which allow air/water pressure to fill the backside of the valve mechanism, which opens via the big spring only when the pressures equalize. It doesn't matter if the equalizing pressure comes from air or water.

So of the solenoid is activated while the pipes have no pressure, nothing happens and the valve remain closed. If the water cutoffs are then opened, air pressure quickly builds behind the valves. Once the pressure reaches the point the valve can operate, the mechanism opens and air exits through the valve into the zone. Eventually, the water "rushes" into the valve, fills the zone pipes, and exits the heads.

Now if the water cutoffs are opened first followed by each zone valve, the exact same thing happens. The only difference is that the required pressure to open valve is present, so the valve opens the instant the solenoid is activated. The air pressure still opens the valve first, water "rushes" into the valve, and eventually the water fills the system.

The question becomes: does the initial water flaw "slam" into the valve and perhaps cause wear or damage? Since solenoid irrigation valves have proven pretty darn reliable for decades, I just don't worry about it.


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## g-man (Jun 15, 2017)

@hsvtoolfool your theory of operation is correct, but I think you are forgetting the pressures. With the valve close, you will have 0psi on one side and ~70psi on the other. When you open the irrigation valve, it will rush in and water hammer with the heads until they open.

If you trigger the irrigation valve to open, yes it won't open, but it will be allowed to open. Once you then slowly open the ball valve, it will crack open at around ~20psi (using hunter spec sheet). This will allow the pipe to fill with less chance of water hammer. Another option, remove the nozzle from each of the runs. This actually also helps to flush the system of debris and recommended by irrigationtutorials.

Can you break the system with either approach? Not really. The pipes/fittings are covered by soil and are unlikely to crack open with burst pressure.

During normal operations, this is not a problem. The pipes reaming with water at around 40psi (based on the heads) and there is no air or compressible fluids).


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## hsvtoolfool (Jul 23, 2018)

I understand @g-man, but I still think it's six of one. It's a fascinating topic though! Perhaps @TommyTester could chime in.

Suppose the mostly empty line is at 70 PSI before the solenoid is activated. When the solenoid is activated and the air pressure opens the valve, the line pressure quickly drops to 20 PSI. I strongly suspect this drop occurs in the 1 to 2 second time-frame, long before the pipes fill and water arrives at the valves. Therefore, the water hits the valve body at 20 PSI, at the same velocity or close enough not to matter if the valve had been open before the main was pressurized. The length of the main pipe and its slope determines how long it takes for the water to fill the main pipe and manifold and get to the open valve. I suppose if the distance is less than five feet, then it's possible for the water to hit the valves between 20 PSI and 70 PSI while the pressure is still dropping. In that case, I agree that opening the valves first would be a good idea.

On a separate but related topic, a Pressure Reducing Valve should be installed between the solenoids and the street. The PRV should be adjusted to drop the system pressure closer to about 50 PSI, which helps tremendously to prevent water hammer. My street pressure is over 100 PSI, so that piece was critical for my system to survive.

I agree 100% about the need to flush the individual heads, but I planned ahead on this count. I have about 30 MP-Rotator heads because my front yard is broken up into small areas. Flushing them all each year would be a major chore. Therefore, I installed an above ground ball-cock on my manifold to flush the system each Spring, blow most of the water out of the main line and manifold in the Fall, and also have a 50 PSI line for a dedicated high-volume watering hose. Finally, I also installed a 120 mesh screen ahead of the valves as Mr Styker recommended for the MP-Rotators. After I've flushed my main lines via the ball-cock and then close it, I then flush the filter for a few minutes to remove trapped debris. So far, I've never found anything in the filter, but it's nice to know it's there.


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## TommyTester (Jul 3, 2018)

@hsvtoolfool ...I don't have any specific experience in this area, unfortunately. :no:


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## g-man (Jun 15, 2017)

Someone beat Tommy on this subject to you tube. I have a one of those anti-surge devices on my main and washer connection. I also use the rachio water hammer feature (opens two valves at once).

https://youtu.be/xoLmVFAFjn4


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## hsvtoolfool (Jul 23, 2018)

I like the video @g-man , your it's just a general overview of water hammer and does not discuss irrigation systems. I hope that it's obvious from my posts that I understand water hammer and the damage it can cause to irrigation systems. When I designed my system, I did all the math from Mr Stryker's old site to keep water velocities at safe levels.

My engineer's gut-feeling is that this is a "MythBusters" scenario. Regardless of the initial conditions, I strongly suspect the pre-water air pressure becomes the same quicker than the water can reach the irrigation valve. You can either open the valve first then build the air pressure to 20 PSI by cracking the water main ball-valve slowly, or you can open the solenoid after the main water valve and the air pressure drops to 20 PSI almost instantly. By the time the water arrives at the irrigation valves, the hammer-effects are about the same regardless which is opened first.

Given his hobbies, I thought TommyTester might find a study of dynamic pressure drop through an irrigation valve interesting. It shouldn't be very expensive or difficult to compare the two cases with a simple test setup.

However, I had a contact at Hunter who once lived here in Rocket City. He's been very helpful in the past with my bizarre nerdy questions about Hunter products. I'll shoot him an email and ask if Hunter has tested this scenario (surely!). It's been years since we spoke, so he may not even work at Hunter any more...

www.hunterindustries.com/spring-start-checklist

The Hunter web page above says "Step 1: Open the system main water valve slowly to allow pipes to fill with water gradually. < blah blah exposition> Step 2: Verify the proper operation of each station valve by manually activating all zones from the controller."

While the Hunter startup check-list supports my argument, step one should actually say "...to allow the pressure to build gradually" because the pipes won't fill with water until the trapped air is let out by opening the valves. Hunter is worried about a sudden pressure build-up inside a closed system. They don't seem to care about water hammer when the valves are opened later. I suspect their valves are designed to withstand much higher forces, for thousands of cycles, than an annual startup.


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## jaygrizzle (Jun 6, 2018)

Thanks for your help @g-man I was able to get everything activated.

However, at the end of last season I noticed some pooling of water near one of the heads. When the guy from the sprinkler company came I showed him the head and it was disconnected. He put on anelbow that attaches to the bottom of the head. He said to dig up the dirt and then I should be able to attach the head back to the line. But when I dug it up I didn't see anyway to connect it. I'm wondering if there is another attachment that isn't an elbow? Or maybe I didn't dig deep enough? Pictures below:


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## g-man (Jun 15, 2017)

You will need to dig more to find the connection.


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