# Need help adding a port for compressor blow out



## static305 (Jun 8, 2020)

I would like to add a valve to my irrigation so i can blow out the system for winter. I read blowing out through the back flow was not a good idea. Not sure how to go about doing this, i would like to install it after the back flow just before the valve box. Would adding a tee with a fitting work? or should i use a compression tee or a slip tee? I have about 2 foot in between the backflow valve and the control valves. Thats where i would add the tee fitting at and put a valve box (Back flow is in the ground). Thoughts and ideas welcomed.

Thanks!


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## TSGarp007 (May 22, 2018)

I can't speak with any experience here, but since there have been no responses... I would think any fitting properly rated for the pressure would be fine. You may be fully aware, but just in case, I'm pointing out that you'll want a valve to isolate the back-flow prevention device from the compressed air. Then the tee fitting would be placed between the isolation valve and the rest of your irrigation system.


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## jht3 (Jul 27, 2018)

Your backflow probably already has ball valves to isolate it? So you can remove it in the winter.

If so, then cut in a T after it. My port has 3/4" male pipe threads, and a 3/4"-1" reducer. And a cap off course.


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## static305 (Jun 8, 2020)

jht3 said:


> Your backflow probably already has ball valves to isolate it? So you can remove it in the winter.
> 
> If so, then cut in a T after it. My port has 3/4" male pipe threads, and a 3/4"-1" reducer. And a cap off course.


This is the Backflow i have. https://www.watts.com/products/plumbing-flow-control-solutions/backflow-preventers/double-check-valve-assemblies/850-small 
So if i put a tee after the back flow and before the valves that would be fine? Something like this https://www.lowes.com/pd/LASCO-1-in-x-1-in-x-1-in-x-1-2-in-dia-Tee-PVC-Fitting/3369486 
Do you think a compression tee would work?
https://www.homedepot.com/pep/Homewerks-Worldwide-3-4-in-PVC-Compression-Tee-with-FIP-Branch-511-48-34-34-34H/206698250?cm_mmc=Shopping-B-F_D26P-G-D26P-26_1_PIPE_AND_FITTINGS-NA-NA-Feed-LIA-NA-NA-PIPE_AND_FITTINGS_General-71700000052572890-58700005047670158-92700047360240749&g_store=3602&gclid=EAIaIQobChMImK3JyaHr6wIVlOeGCh3ikAwnEAQYBSABEgK4wPD_BwE&gclsrc=aw.ds&locale=en-US&mtc=Shopping-B-F_D26P-G-D26P-26_1_PIPE_AND_FITTINGS-NA-NA-Feed-LIA-NA-NA-PIPE_AND_FITTINGS_General&source=shoppingads
Are you suggesting i remove the back flow for winter? New to this, So sorry if im not making since.

Thanks!


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## TSGarp007 (May 22, 2018)

The manufacture has procedures for freeze protection on the site you linked. I have something similar to that device but don't have to worry much about the freezing. That last ball valve should isolate your backflow, so you'll be able to put the tee fitting anywhere after that. I'm not sure why you would plan on ever removing the tee fitting, so I would just use the slip version.


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## static305 (Jun 8, 2020)

TSGarp007 said:


> The manufacture has procedures for freeze protection on the site you linked. I have something similar to that device but don't have to worry much about the freezing. That last ball valve should isolate your backflow, so you'll be able to put the tee fitting anywhere after that. I'm not sure why you would plan on ever removing the tee fitting, so I would just use the slip version.


No plans to remove the back flow, was just asking from other persons response. The compression tee was just a thought for ease of installation. But i will go with a slip tee and make a permanent install. Thanks for all the help and reassurance before i tackle this project this weekend!


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## jht3 (Jul 27, 2018)

Some municipalities required annual testing if backflow preventers, which requires removal. Mine doesn't and my backflow is in the basement so it won't freeze.

I would about compression fittings. Glued up pvc won't fail.


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## static305 (Jun 8, 2020)

Last question. I have 7 zones all spray heads except one that is a drip irrigation for my shrubs. How do i blow out the drip irrigation line?


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## TSGarp007 (May 22, 2018)

I would make sure the air pressure is below all the limits for your drip system (tubing, fittings, etc.). If you have a pressure reducing device, it is probably based on water going through it, so I don't think you can rely on that to reduce any air pressure in the line.


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## jht3 (Jul 27, 2018)

Good question, I don't know? I don't have any drip zones but I want to add some. My only thought is to turn down the pressure at your compressor


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## hsvtoolfool (Jul 23, 2018)

I installed a regular hose bib on each side of my backflow preventer. I also put a hose bib near my manifold. They are hidden in ground boxes. They allow me to both flush and drain the mainline from curb to manifold. They also allow me to connect a garden hose for full curb pressure and flow. It's a cheap man's presssure washer.

To blow out the pipes, I made an adapter from parts sourced at Lowe's/Home Depot/Harbor Freight. I don't recall where I got them, but it was all off-the-shelf stuff. The main part is a 3/4" brass FHT (Female Hose Taper) adapter that scews onto the hose bib, followed by a 1/2" NPT to 3/8" NPT male reducer, then finally a 3/8" male air coupler. Or something like that. I cobbled it together in the store.


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