Register free!
Search
 
     

Click for Weather
Reply
 
Thread Tools Display Modes
  #1  
Old 07-30-2008, 07:04 PM
Waterit's Avatar
Waterit Waterit is offline
LawnSite Silver Member
 
Join Date: May 2008
Location: NW Florida
Posts: 2,735
Dumb questions (maybe) but I'd like to know

The setup:

(2) 7-1/2HP submersibles, each producing about 120GPM @ 70PSI +/-, and tied into same 2-1/2" mainline. Each well has 2" pressure relief valve BEFORE 2" PVB.

33 zones spread across (2) ICC's, each ICC has its own Hunter PSR-B and each controls one well.


The questions:
1) There is no protection from one well pumping against the other except for the PVB's, which I don't think are built to withstand that much flow at that much pressure. I want to install a check valve AFTER each PVB to prevent the back-pressuring between pumps. Good idea/bad idea? If good, what size check? Match mainline size, or go bigger?
2. When either pump first turns on, there is a horrendous hammer effect on the piping, specifically the MA coming out of the PVB and the 1st 90 that turns the pipe vertical. It was suggested to install a pressure tank to absorb some of this hammer. Smart/stupid? If smart, what size tank?

::::moves away from keyboard, looks for fireproof suit::::
__________________
BK

Last edited by Waterit; 07-30-2008 at 07:06 PM. Reason: Added and then edited smart-@$$ closing remark
Reply With Quote
  #2  
Old 07-30-2008, 07:37 PM
Wet_Boots's Avatar
Wet_Boots Wet_Boots is offline
LawnSite Fanatic
 
Join Date: Mar 2005
Location: metro NYC
Posts: 40,000
Too bad you can't have the supply under continuous pressure, with tanks and pressure switches (and maybe even CSVs)
Reply With Quote
  #3  
Old 07-30-2008, 07:41 PM
greenmonster304's Avatar
greenmonster304 greenmonster304 is online now
LawnSite Silver Member
 
Join Date: Jul 2007
Location: You Know
Posts: 2,453
it seems to me if you had a check valve on each well and they are plumbed into the same main if there was ever a pressure difference between the two wells the one with weaker pressure would not be able to open. But i might be missing some factor.
Reply With Quote
  #4  
Old 07-30-2008, 07:42 PM
Waterit's Avatar
Waterit Waterit is offline
LawnSite Silver Member
 
Join Date: May 2008
Location: NW Florida
Posts: 2,735
Quote:
Originally Posted by Wet_Boots View Post
Too bad you can't have the supply under continuous pressure, with tanks and pressure switches (and maybe even CSVs)
Could have it that way, but personally I like a straight pump-start with a well. And with the volume of water (and lack of irrigation knowledge amongst the maintenance staff) I'll probably be leaving it a straight pump-start.
__________________
BK
Reply With Quote
  #5  
Old 07-30-2008, 07:48 PM
Wet_Boots's Avatar
Wet_Boots Wet_Boots is offline
LawnSite Fanatic
 
Join Date: Mar 2005
Location: metro NYC
Posts: 40,000
But you do cure the startup hammer with a 24/7 pressurized setup.
Reply With Quote
  #6  
Old 07-30-2008, 07:53 PM
Mike Leary's Avatar
Mike Leary Mike Leary is offline
LawnSite Fanatic
 
Join Date: Mar 2007
Location: Cactus Hug, Arizona
Posts: 20,552
[QUOTE=Waterit;2443205 personally I like a straight pump-start with a well. .[/QUOTE]

Ditto, or on demand.
Reply With Quote
  #7  
Old 07-30-2008, 07:58 PM
bcg bcg is offline
LawnSite Bronze Member
 
Join Date: Mar 2005
Location: Tx
Posts: 1,774
Or, you could just replace the PVB's with RP's. PVB's aren't rated for back-pressure at all so if you're worried about that, then you definitely do need to do something.
Reply With Quote
  #8  
Old 07-30-2008, 08:12 PM
bicmudpuppy's Avatar
bicmudpuppy bicmudpuppy is offline
LawnSite Silver Member
 
Join Date: Apr 2005
Location: Aztec, NM
Posts: 2,792
I'm reading ONE main line. Why is the PVB after EACH pump? One PVB with check valves to protect the pumps from each other would be a better setup, but I'm not there looking at it. A single pump start being shared by two controllers is another nightmare, especially if the controllers are a significant distance apart. If your worried about down stream leaks, switching to a MV and putting the pumps on pressure switches would be easier and safer. Stacking the pressure switches for demand would again be safer for all aspects. If hours on the pump is an issue, then you can trade the sequence of primary and secondary either by installing plugs that could be switched, or by trading the switches annually. The worst part of these type of questions is NOT being there. I would bet that some obvious solutions would be there for many of us if we were on site.

Any chance of some pictures?
__________________
Over educated
Over Qualified
Glorified Ditch Digger
....but still a bargain compared to anything else.
And I NEVER say I told you so out loud.
How many Hats can you wear?
Reply With Quote
  #9  
Old 07-30-2008, 09:39 PM
Mike Leary's Avatar
Mike Leary Mike Leary is offline
LawnSite Fanatic
 
Join Date: Mar 2007
Location: Cactus Hug, Arizona
Posts: 20,552
[QUOTE=bicmudpuppy;2443252 I would bet that some obvious solutions would be there for many of us if we were on site[/QUOTE]

I love my wife, dog, motor home, pump experts... in that order.
Reply With Quote
  #10  
Old 07-30-2008, 10:15 PM
Waterit's Avatar
Waterit Waterit is offline
LawnSite Silver Member
 
Join Date: May 2008
Location: NW Florida
Posts: 2,735
Quote:
Originally Posted by bicmudpuppy View Post
I'm reading ONE main line. Why is the PVB after EACH pump? One PVB with check valves to protect the pumps from each other would be a better setup, but I'm not there looking at it. A single pump start being shared by two controllers is another nightmare, especially if the controllers are a significant distance apart. If your worried about down stream leaks, switching to a MV and putting the pumps on pressure switches would be easier and safer. Stacking the pressure switches for demand would again be safer for all aspects. If hours on the pump is an issue, then you can trade the sequence of primary and secondary either by installing plugs that could be switched, or by trading the switches annually. The worst part of these type of questions is NOT being there. I would bet that some obvious solutions would be there for many of us if we were on site.

Any chance of some pictures?
Two pumps, two controllers, two pump-starts, one mainline, although each pump has its own feed into mainline. Don't know where mainline is tied together (we didn't do original install, just controls package).

PVB's are mounted on top of each pump - remember they are submersible pumps.

I may put in MV's, that would solve with back-pressure problem, but REALLY hate the idea of going to pressure switches, especially on 440VAC 3-phase pumps.

Will take pics tomorrow and post.
__________________
BK
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 08:11 AM.

Page generated in 0.09830 seconds with 8 queries