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  #1  
Old 08-13-2008, 09:35 AM
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csmlawn csmlawn is offline
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Low Head Drainage and Check Valves

When you have a hill type grade and the lowest head on the zone doesn't go down all the way when it shuts off and drains until there is no water left in the pipe, does that mean there is no check valve in the head?

FYI... All other heads in the zone go down and no water comes out.

Thanks.
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Old 08-13-2008, 10:03 AM
Kiril Kiril is offline
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What is the elevation change?

If you want to know if the head has a check, then pull the head and "check".
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Old 08-13-2008, 10:07 AM
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Waterit Waterit is offline
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Quote:
Originally Posted by csmlawn View Post
When you have a hill type grade and the lowest head on the zone doesn't go down all the way when it shuts off and drains until there is no water left in the pipe, does that mean there is no check valve in the head?

FYI... All other heads in the zone go down and no water comes out.

Thanks.
A successful diagnosis. You are a sprinkler man!
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  #4  
Old 08-13-2008, 01:08 PM
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csmlawn csmlawn is offline
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LOL!!! I don't even know what one looks like... anyone have any pics? I've pulled two heads to examine, but the cap screw was on so tight on both I couldn't check them. According to WM, the T3 rotor comes with a check valve... However, my low heads piss like racing horses. The elevation change is about 6 feet (if that).
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  #5  
Old 08-13-2008, 01:12 PM
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BrandonV BrandonV is online now
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depends on the amount of head. I know that the pro sprays we use will only hold back 10' of head you might need to install an online check valve.
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Old 08-13-2008, 02:13 PM
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Mike Leary Mike Leary is offline
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Quote:
Originally Posted by tomscreek View Post
depends on the amount of head. I know that the pro sprays we use will only hold back 10' of head you might need to install an online check valve.
Beep beep..warning: the inline check valves eat pressure for breakfast.
The more head you need to adjust for, the higher the psi loss.
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Old 08-15-2008, 02:29 PM
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csmlawn csmlawn is offline
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Quote:
Originally Posted by Mike Leary View Post
Beep beep..warning: the inline check valves eat pressure for breakfast.
The more head you need to adjust for, the higher the psi loss.
Hi Mike,

Can you explain more on this?
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Old 08-15-2008, 02:51 PM
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Mike Leary Mike Leary is offline
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Quote:
Originally Posted by csmlawn View Post
Hi Mike,
Can you explain more on this?
The Hunter low-drain check valve is adjustable from 4' to 32'. As the height
increases, the friction loss does also. It is factory set for 12' with a friction
loss of 7 psi. With 32' of height, the loss is 15 psi, so you can see the need
to be very careful adjusting it just enough to prevent low drainage. The amount
of loss is also tied to your gpm, and the loss can screw you.
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Old 08-15-2008, 03:02 PM
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Mike Leary Mike Leary is offline
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Here's cut sheet.

www.hunterindustries.com/resources/pdfs/instructions/domestic/23561w.pdf
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  #10  
Old 08-15-2008, 03:22 PM
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irritation irritation is offline
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Where's your friction loss data?
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