# Irrigation system Design



## Johngnbtr (Sep 27, 2018)

Hi All,

I have irrigation system that is working with Melnor 4 zone water timer without valve box. System works great so far but I would like have Rainbird controller installed to my garage instead of hose timer. Below is my new system design. Can you please tell me if that would work fine ?

Thank you so much in advance for all your comments 

Thanks,

John


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## SW315 (Sep 10, 2018)

Couple things, 1/2" line will be too small. Is this an in-ground system, if so you will need a backflow preventer installed before your valves.


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## Johngnbtr (Sep 27, 2018)

SW315 said:


> Couple things, 1/2" line will be too small. Is this an in-ground system, if so you will need a backflow preventer installed before your valves.


Hi ,

Thank you for your comment. It will be 1" schedule 40 pvc underground . I have main water line coming to my basement and outdoor faucet is connected to main line in basement with 1/2" copper pipe. If you look at the design I have 1/2" x 1' PVC elbow to increase 1/2 " PVC pipe to 1" pvc pipe going to the valve box. For Backflow I was thinking using double check valve. Do you think I should install backflow preventer ? If I should , do you have any suggestion for brand and model?
and also should I install it inside the basement or outside before the valve box?
Thanks


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## SW315 (Sep 10, 2018)

The 1\2" that you are tapping in to will not be enough even with your 1" laterals. Yes a backflow is needed. There are many different types to choose from. You may have to do some calling around to find out what is used in your area. A PVB (Pressure Vacuum Breaker) type is very common for residential systems. https://www.irrigationtutorials.com/ is a great site with a ton of information on irrigation systems.

Hope that helps.


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## Johngnbtr (Sep 27, 2018)

Do you think it will be ok, if I tap into mainline (3/4" copper pipe) with 3/4" pvc pipe in the basement? Then use 3/4" x 1" pvc elbow to increase to 1" pvc to go valve box?


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## g-man (Jun 15, 2017)

I have a couple of comments. First I'm not in favor of PVC in the basement. A crack and you will have a mess. If you have to, then at least have the T and ball valve in copper or PEX. I don't think it will be up to code to use pvc, but you need to check with your city/county.

Most city will require a backflow and will have a minimum requirements. The double check is not typical to be an approved method. It normally need to be testable and test once a year.

I strongly suggest going irrigationtutorials.com and reading the whole tutorial. The owner has done a great job with the content.


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## Johngnbtr (Sep 27, 2018)

Thank you for your help

This is what I have found on website of the city.

All residential lawn irrigation systems are required to have either a pressure vacuum breaker (PVB) or a reduced pressure zone (RPZ) backflow preventer. All hose bibbs are required to have an atmospheric vacuum breaker.

Do you have suggestion for good brand ?


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## SW315 (Sep 10, 2018)

For a PVB the Febco 765 is a good choice. It needs to be installed 12" above your highest outlet. If you are installing in your basement, you will need a RPZ type. They are more expensive and you also need to install a drain for the relief valve.


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## Johngnbtr (Sep 27, 2018)

SW315 said:


> For a PVB the Febco 765 is a good choice. It needs to be installed 12" above your highest outlet. If you are installing in your basement, you will need a RPZ type. They are more expensive and you also need to install a drain for the relief valve.


Thank you for your reply. I think I will tap into mainline in the basement before or after the shutoff . It will be all copper pipe coming outside . I will connect sharkbite copper to pvc coupling outside and take it to valve box . before the coupling i will install PVB . Would that work ?


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## g-man (Jun 15, 2017)

Tap the main with a T after the house main shutoff, then a ball valve, then go outside with the copper. Install the PVB, after the output of the PVB, either switch to PVC or keep it at copper until the valve box. Because I'm OCD, I would also install a master valve before the valve manifold. Master valve is only a few dollars more, but will save you a ton of money if one of the valves fails open (rare, but possible).

Match your main line cooper size or go one size bigger, dont go smaller.


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## Johngnbtr (Sep 27, 2018)

g-man said:


> Tap the main with a T after the house main shutoff, then a ball valve, then go outside with the copper. Install the PVB, after the output of the PVB, either switch to PVC or keep it at copper until the valve box. Because I'm OCD, I would also install a master valve before the valve manifold. Master valve is only a few dollars more, but will save you a ton of money if one of the valves fails open (rare, but possible).
> 
> Match your main line cooper size or go one size bigger, dont go smaller.


Thank you so much for your help and suggestions G-Man and SW315 . I will follow your directions and start working on it .


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## Johngnbtr (Sep 27, 2018)

g-man said:


> Tap the main with a T after the house main shutoff, then a ball valve, then go outside with the copper. Install the PVB, after the output of the PVB, either switch to PVC or keep it at copper until the valve box. Because I'm OCD, I would also install a master valve before the valve manifold. Master valve is only a few dollars more, but will save you a ton of money if one of the valves fails open (rare, but possible).
> 
> Match your main line cooper size or go one size bigger, dont go smaller.


Hi G-Man,

I draw picture according to your instructions as below:


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## SW315 (Sep 10, 2018)

That looks good.


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## Johngnbtr (Sep 27, 2018)

SW315 said:


> That looks good.


Thank you . Thank you so much for your help.


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## g-man (Jun 15, 2017)

This looks good. The only things I do different (I'm OCD), I use the thicker copper (Type M or K or some letter) and schedule 80 up to the master valve. It is an overkill, but since it is an exposed pipe, I want all the protection I could get. That bracket holding the pipe to the siding is also a good idea.


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## Johngnbtr (Sep 27, 2018)

g-man said:


> This looks good. The only things I do different (I'm OCD), I use the thicker copper (Type M or K or some letter) and schedule 80 up to the master valve. It is an overkill, but since it is an exposed pipe, I want all the protection I could get. That bracket holding the pipe to the siding is also a good idea.


I think you are right about putting schedule 80 up to the master valve and also thicker copper that would definitely help to keep it protected during winter. Thank you so much for your advice . How should I design the valve box. When I looked at Rainbird irrigation installation video, they do put 3 inches between valves. I see some people they put drain to the end of the manifold .How Should I do design ?


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## Johngnbtr (Sep 27, 2018)

g-man said:


> This looks good. The only things I do different (I'm OCD), I use the thicker copper (Type M or K or some letter) and schedule 80 up to the master valve. It is an overkill, but since it is an exposed pipe, I want all the protection I could get. That bracket holding the pipe to the siding is also a good idea.


Hi G-Man,

I wanted measure water pressure coming from the hose yesterday. I put water pressure gauge and it reads 100 psi.
It seems too high . Should I install pressure regulator to the mainline in the basement?

Do you have any suggestion for a brand and model for 3/4" copper pipe? I saw a sharkbite pressure regulator with gauge. Do you think they are any good?


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## g-man (Jun 15, 2017)

100 psi from city water? That's high. You should regulate the whole house down. Your appliances will benefit.

I would call your utility company to confirm the pressures and make sure they don't have something wrong on their end.

I don't have experience with the sharkbite pressure regulator.


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