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The last 7 posts

Wednesday, May 18th 2011, 1:58pm

by wsommariva

Op here. I have 3/4" running from meter to PVB and then to the 3/4" valves and then to 3/4" PE that runs to all heads. I have 5.5 gpm and working pressure in the low 40s. Toro did the original design and I made some adjustments. System works very well.

Wednesday, May 18th 2011, 9:08am

by HooKooDooKu

RE: RE: PVB winter

Just tape the openings in the piupe after removing the PVB. Question, though... 3/4" is rarely used and only allows 8-10 gpm through. Curious why this was chosen as size pipe.
Uhhh, you do realize that backflow preventers are rated for the same flows as equivalent water meters. That means a one-inch PVB is rated for 50 gpm, not that anyone would plan for that flow.


I'm assuming he's refering to the pipe size, not the size of the backflow preventer. Of course 8-10 gpm in a 3/4" pipe is going to put you more towards 7fps rather than the 5fps limit suggested now-a-days. So for 3/4" pipe, the design flow should be more around 6-7 gpm.

Then again, the OP didn't say anything about the pipes for the rest of the system, just what is at the PVB. I know that my water supply is via a 3/4" meter, but the pipe just past it is 1" PVC.

Tuesday, May 17th 2011, 6:55pm

by Wet_Boots

RE: PVB winter

Just tape the openings in the piupe after removing the PVB. Question, though... 3/4" is rarely used and only allows 8-10 gpm through. Curious why this was chosen as size pipe.
Uhhh, you do realize that backflow preventers are rated for the same flows as equivalent water meters. That means a one-inch PVB is rated for 50 gpm, not that anyone would plan for that flow.

Tuesday, May 17th 2011, 5:36pm

by lawn sprinklers

PVB winter

Just tape the openings in the piupe after removing the PVB. Question, though... 3/4" is rarely used and only allows 8-10 gpm through. Curious why this was chosen as size pipe.

Monday, May 16th 2011, 6:33am

by wsommariva

OK I can make them. Good idea thank you

Sunday, May 15th 2011, 8:42pm

by HooKooDooKu

If you want to close where the PVB was installed... since you are going to install it with unions, you could always get another matching set of unions connected to "dead-end" pipes. Unscrew the PVB and screw on the "dead-ends" and your system remains closed to outside "critters".

Sunday, May 15th 2011, 7:53am

by wsommariva

Best way to install PVB

Hi everyone. I have two small leaks at the npt fittings to my pvb, so I will reinstall it. I'll use unions so that I can tighten the fittings after installation.

Is there a better method? Also the union will enable me to take the pvb inside in the winter. How do I cover up the 3/4" holes in the pvc - just tape it?

Thanks