Bama, I don't understand check valves enough to understand your reasoning. But, what I get from your post is the check valves will not work properly when the LQ water level is close to the water level of the pool. However, the picture of Barnyard's setup on page 5 shows the top of the LQ at about the same level as the bottom of the skimmer - presumably several inches below the water level in the pool. Do I misunderstand your post?
Liquidator installed below pool level
- Thread starter brywisco
- Start date
Just a brief explanation. There is a spring inside the check valve that holds it closed. Once seated the spring pressure and the stiction of the seat requires a set amount of pressure in the forward direction to open the check valve and start the fluid to flowing. On the check valves we're using that pressure is about .3psi or .78 feet of head. So if you screwed a length of pipe on the inlet side of the check valve, held it valve down and filled it a foot deep water, the water would flow out until the column got low enough that the spring pressure overcame it and shut off the flow. However if you placed 6" of water on top of it the spring tension and seat stiction would keep the water from flowing out.
That was longer than I'd hoped for! If I'm rambling please somebody slap me. :blah:
That was longer than I'd hoped for! If I'm rambling please somebody slap me. :blah:
At this point I don't want to cut up any plumbing but I appreciate the suggestionTxmat said:
I'm thinking the opposite, move the check valve closer to the tank. You and I both have our valves down low, near the pump. The tank water level is much higher than the valve. I'm speculating that it is the weight water in the tubing from the tank that is holding the lower elevation valve open.....then water from the suction side leaks back upwards. Now if you move the suction connection point to a higher elevation and place the valve close, then that may help. Bring the valve up as high as possiblebarnyard said:
That is correct, the spring should eliminate the need for orientation, but these are pretty weak springsbarnyard said:
Agreed. BUT Since I have low flow due to proxoimity, I keep my flow valve wide open...do you? Would this make a difference in static head in the tubing? If not then the only difference between us would be the springs....back to the defective lot theory.Bama Rambler said:
12" elevation difference between LQ water level and tubing into suction port. Head against the back side of valve varies since I keep moving valve, max would be 12"Bama Rambler said:
Water level in the pool is 16" higher than water level in the LQ.
:? Could this 4" be a factor? My setup is nearly identical to yours (pool is ongrade, LQ is slightly above on slab) except it is a 52" depth. If I am following your reasoning, this should make mine LESS likely to leak, no?
I think I'm starting to understand where Bama is coming from. I have to restrict my thinking to static forces only. Flow has nothing to do with it. What we are trying to balance is the forces on each side of the check valve, which is under pressure on BOTH sides when the pump is stopped.
O = the pressure against the OUT side of the valve is from the difference between the POOL water level and the valve elevation PLUS the spring
I = the pressure against the IN side of the valve is from the difference between the LQ water level and the valve elevation
When I > O, we have normal flow
When O > I, we have no flow and the valve stays closed
So what happens when I = O? Potentially Seeping backflow
To adjust this balance, increase O or decrease I:
1) Increase O by stronger spring
2) Increase O by moving valve lower relative to pool water level
3) Decrease I by moving valve higher relative to LQ water level
Note...#2 and #3 oppose each other
O = the pressure against the OUT side of the valve is from the difference between the POOL water level and the valve elevation PLUS the spring
I = the pressure against the IN side of the valve is from the difference between the LQ water level and the valve elevation
When I > O, we have normal flow
When O > I, we have no flow and the valve stays closed
So what happens when I = O? Potentially Seeping backflow
To adjust this balance, increase O or decrease I:
1) Increase O by stronger spring
2) Increase O by moving valve lower relative to pool water level
3) Decrease I by moving valve higher relative to LQ water level
Note...#2 and #3 oppose each other
OK...replying to my own post from a couple days ago. I'm now at 48 hours with no overflows with the above configuration. Not sure if it is a solution or a coincidence. The valves ARE at a higher elevation than before, one with the arrow pointed up and the other horizontal[attachment=0:3vqxhjz4]018.JPG[/attachment:3vqxhjz4].Miranda said:
Attachments
In your last pic I can absolutely believe that it hasn't overflowed. It will take a long time of it not overflowing for any of us to believe it's not going to.
I'm delighted that you guys are all working so hard to find a solution or solutions. Early on in the year I asked a question about using the Liquidator, in my flooded pumping station. My pumping station is almost as low as the bottom drain on my 10' deep end, with the filter only set about 30" above the rest of the pumping station. So water has tremendous pressure going into the valves before pump, is then pumped up a couple of feet, and then horizontally 10', or so, to the filter, filter (pressure side) is pumped up, across about 10', then drops back down to the valves going to returns to pool, which is a good rise up vertically (more pressure from that side when system off). Sooooooooooooooo, I'm going to let you guys get all the kinks out before I even attempt to install one in my system. If I spent as much time as could possibly be needed to trouble shoot DH would lock me in a room and never let me see the pool. :grrrr:
I really really admire your determination and you guys know that some of us will be very appreciative of your work on this ..... well actually, this girlie really, really appreciates your work LOADS right now.
:-D
Thanks, gg=alice
I really really admire your determination and you guys know that some of us will be very appreciative of your work on this ..... well actually, this girlie really, really appreciates your work LOADS right now.
:-D Thanks, gg=alice
Did you mean "CAN'T believe it hasn't overflowed yet?" Does it make any sense to you how this would fix it?Bama Rambler said:
No overflows yet going on 3 days. I'm afraid to touch anything....but when I do my next test will be to take one of the valves out. Barnyard, can you try something similar and see if it works for you?
Up for my 2:00 am inspection, still no overflow after 64 hours. I'm going to call this a preliminary success, since it is the first setup that has made it 24 hours without an overflow.
Next test (starting now): Same setup as above, but I have removed one of the two check valves in series.
Next test (starting now): Same setup as above, but I have removed one of the two check valves in series.
Miranda said:
I have been out of commission the last couple of days with work and anniversary (gotta keep the wife happy so she will continue to let me work on this thing
)I should be able to do the acid wash this morning and start getting it all hooked back up. If I am reading everything right, I need to get a check valve as high as possible right? either at the LQ level or above? I am up for giving it a shot. I have been adding chlorine manually, so this time I am going to run the LQ with just water to eliminate any WS issue and see where that gets me. Once I feel better about it, I will add the chlorine.
Nice work Miranda, you have certainly put a lot of effort into this thing.
Sal, let us know when you have had the chance to test the other check valve. I am curious of the results of that.
Bama, It seems you don't think Miranda's setup will work. Why? You certainly have knowledge in this area, so it would be helpful to hear your thoughts on this latest development.
Maybe I stated it a little obtusely.
I do believe Miranda's setup will work without issues. With the check valve above the level of the LQ the head has effectively been changed and it shouldn't overflow. That lends to my theory that the head created by the LQ level is the cuprit. I hate it took this long to figure it out and untill a little more "no overflow" time has passed I'll still be crossing my fingers that it was the issue.
I do believe Miranda's setup will work without issues. With the check valve above the level of the LQ the head has effectively been changed and it shouldn't overflow. That lends to my theory that the head created by the LQ level is the cuprit. I hate it took this long to figure it out and untill a little more "no overflow" time has passed I'll still be crossing my fingers that it was the issue.
Bama Rambler said:
Great. That is what I will try then. Do you think that if the check valve was even with the outflow valve that the head would be sufficiently reduced? Of course, I am getting tired of reconfiguring, so I might as well try and get it above the LQ as far as possible I guess. Of course, I still need to figure out this WS thing.
Here's to hoping it works!!!!
C'mon, all women have a "pool boy" fantasy. Buy her a nice float with a drink holder. Keep her drink filled while she floats and remind her that she looks more beautiful than the day you met.....barnyard said:I have been out of commission the last couple of days with work and anniversary (gotta keep the wife happy so she will continue to let me work on this thing
I have removed the second valve and it is still holding (9 hours now). So now my one check valve is about even with the water level in the LQ. The bottom of the flow meter is 2" above the liquidator lid. Looking at your picture and trying to make it similar, I would first move the flow meter up higher on the pipe until the bottom is just an inch or two above the liquidator lid. Then I would hang the check valve directly below it at about liquidator water level, then attach the rest of the tubing as needed. My flow control valve is on the other side of the flow meter, but that shouldn't matter. Most importantly, do NOT remove the ziptie tails...then shout "Roll Tide" and "Go Gators" and let her rip.barnyard said:
A couple lingering questions. DO we have the same check valve? (Mine is black with white threaded nipples attached, in the pics, Bama and BY's look more like the gray, one piece OEM type) Bama, your check valve appears to be down pretty low, with this new theory, why isn't yours overflowing?
Miranda: I am watching this to see where you end up (I love the comment about leaving the zip tie tails too :lol: ). We have these installed on vanishing edge pools with much greater elevation change, and water pressure, with no issues. Yours, and barnyards, situation is just plain weird and confusing. I hope through all of this a solution comes to light.
barnyard: I suffer from WS as well, and have to take my system apart to clean it more often than I would like. My water is well balanced, so I do not think that is the culprit. The WS seems somewhat like crystallized salt, and somewhat like calcium (my CH level is 220); maybe a cross between the two, if that makes any sense. I cracked my flow meter (don't know why I really need it, so I just took it out. I check my levels so often that I can just adjust as needed, like I do anyway!) and was drawing air, so I have now reconfigured the whole setup, and I put a "filter" in line to catch the WS. I just did that last night, so I will have to see how it works. I do know that the WS impeded the movement of the float ball, and slowed the flow in my check valves also. At first I thought that maybe the WS was from the WalMart bleach, so I switched to the 12.5% pool supply stuff, hoping to see a change; nothing!
Keep us all posted! I'd love to see a solution to all of this!
barnyard: I suffer from WS as well, and have to take my system apart to clean it more often than I would like. My water is well balanced, so I do not think that is the culprit. The WS seems somewhat like crystallized salt, and somewhat like calcium (my CH level is 220); maybe a cross between the two, if that makes any sense. I cracked my flow meter (don't know why I really need it, so I just took it out. I check my levels so often that I can just adjust as needed, like I do anyway!) and was drawing air, so I have now reconfigured the whole setup, and I put a "filter" in line to catch the WS. I just did that last night, so I will have to see how it works. I do know that the WS impeded the movement of the float ball, and slowed the flow in my check valves also. At first I thought that maybe the WS was from the WalMart bleach, so I switched to the 12.5% pool supply stuff, hoping to see a change; nothing!
Keep us all posted! I'd love to see a solution to all of this!
My check valve is the black one that will unscrew at the buldge. It's barely visible in the pic because it's below and behind the flow control (gray) valve. If you look real close you can see it right in front of the pump basket lid.
Mine doesn't overflow because the water level in the LQ is well below the water level in the pool, creating plenty of back pressure against the check valve to keep the valve checked. Well, that and the fact that I never trimmed my zip tie tails. :-D
Mine doesn't overflow because the water level in the LQ is well below the water level in the pool, creating plenty of back pressure against the check valve to keep the valve checked. Well, that and the fact that I never trimmed my zip tie tails. :-D