Register free!


Reply
 
Thread Tools   Display Modes
  #1  
Old 09-09-2010, 11:47 PM
No Rush's Avatar
No Rush No Rush is offline
LawnSite Member
 
Join Date: Sep 2006
Location: South Texas
Posts: 202
Hyd. Pressure at PVB

Some back ground info - I am designing an irrigation system for a park (8.62 acres); the current PVB is about 400 ft from the 1.5" meter and the line from the meter to the PVB is 2" sch. 40. The meter is coming off of a 6" city main line.

I put two different pressure gauges on test **** one of the PVB and get 68 psi. I even tried putting a gauge on test **** two and got a close reading.

I call the city water dept for verification of water pressure and they tell me the most pressure to that area is 55 psi.

Am I missing something here?
__________________
Texas Licensed Irrigator
Texas Licensed Backflow Tester

When a person with money meets a person with experience, the person with experience will get some money and the person with money will get some experience. -Harvery MacKay
Reply With Quote
  #2  
Old 09-09-2010, 11:49 PM
DanaMac's Avatar
DanaMac DanaMac is online now
LawnSite Fanatic
 
Join Date: Mar 2002
Location: Somewhere in the state of CO
Posts: 13,096
Did you check the stagnant pressure?
Reply With Quote
  #3  
Old 09-09-2010, 11:52 PM
No Rush's Avatar
No Rush No Rush is offline
LawnSite Member
 
Join Date: Sep 2006
Location: South Texas
Posts: 202
68 psi was the static pressure at the PVB.
__________________
Texas Licensed Irrigator
Texas Licensed Backflow Tester

When a person with money meets a person with experience, the person with experience will get some money and the person with money will get some experience. -Harvery MacKay
Reply With Quote
  #4  
Old 09-09-2010, 11:57 PM
DanaMac's Avatar
DanaMac DanaMac is online now
LawnSite Fanatic
 
Join Date: Mar 2002
Location: Somewhere in the state of CO
Posts: 13,096
Quote:
Originally Posted by No Rush View Post
68 psi was the static pressure at the PVB.
Stagnant, not static. Inside joke for the old timers. Nevermind.
Reply With Quote
  #5  
Old 09-10-2010, 12:00 AM
mitchgo's Avatar
mitchgo mitchgo is offline
LawnSite Silver Member
 
Join Date: Dec 2008
Location: Redmond, WA
Posts: 2,671
Elevation change....
Reply With Quote
  #6  
Old 09-10-2010, 12:00 AM
No Rush's Avatar
No Rush No Rush is offline
LawnSite Member
 
Join Date: Sep 2006
Location: South Texas
Posts: 202
ok - ok...I'll be there one day
__________________
Texas Licensed Irrigator
Texas Licensed Backflow Tester

When a person with money meets a person with experience, the person with experience will get some money and the person with money will get some experience. -Harvery MacKay
Reply With Quote
  #7  
Old 09-10-2010, 12:10 AM
No Rush's Avatar
No Rush No Rush is offline
LawnSite Member
 
Join Date: Sep 2006
Location: South Texas
Posts: 202
Quote:
Originally Posted by mitchgo View Post
Elevation change....
If there is any elevation change it's not more that 1'
__________________
Texas Licensed Irrigator
Texas Licensed Backflow Tester

When a person with money meets a person with experience, the person with experience will get some money and the person with money will get some experience. -Harvery MacKay
Reply With Quote
  #8  
Old 09-10-2010, 01:44 AM
mitchgo's Avatar
mitchgo mitchgo is offline
LawnSite Silver Member
 
Join Date: Dec 2008
Location: Redmond, WA
Posts: 2,671
That's a flat 400' run

I wouldn't worry about it. Water districts can be wrong. I mean they don't even have a way to read psi at the meter ( you would think a meter could have a built in psi gauge ) Beside 68 is much better then 55

How about the main road leading the park, any elevation change?
Reply With Quote
  #9  
Old 09-10-2010, 05:56 AM
FIMCO-MEISTER's Avatar
FIMCO-MEISTER FIMCO-MEISTER is offline
LawnSite Fanatic
 
Join Date: May 2007
Location: Red State America
Posts: 18,701
Check your gauge for sure. Maybe try a second gauge. (never mind. I reread and you used two gauges) Not sure what the time of day was but try a reading during peak water usage. I know John's Dad puts a cya in on design pressure in his plans. The final pressure reading is up to the installer and adjustments need to be made accordingly. Course you may be doing the install as well. I guess if you are confident in your readings you could split the difference with the 55 and go from there. Definitely worth investigating a little more.
Reply With Quote
  #10  
Old 09-10-2010, 07:19 AM
No Rush's Avatar
No Rush No Rush is offline
LawnSite Member
 
Join Date: Sep 2006
Location: South Texas
Posts: 202
Quote:
Originally Posted by FIMCO-MEISTER View Post
Check your gauge for sure. Maybe try a second gauge. (never mind. I reread and you used two gauges) Not sure what the time of day was but try a reading during peak water usage. I know John's Dad puts a cya in on design pressure in his plans. The final pressure reading is up to the installer and adjustments need to be made accordingly. Course you may be doing the install as well. I guess if you are confident in your readings you could split the difference with the 55 and go from there. Definitely worth investigating a little more.
I have designed the system using the numbers the city told me (55psi) but, I am pushing them for verification of the water pressure in that area. So far no one from the city has been out there. I am just trying to CMA.
__________________
Texas Licensed Irrigator
Texas Licensed Backflow Tester

When a person with money meets a person with experience, the person with experience will get some money and the person with money will get some experience. -Harvery MacKay
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump






Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ©1998 - 2012, LawnSite.comô - Moose River Media
All times are GMT -4. The time now is 06:07 AM.

Page generated in 0.08859 seconds with 8 queries