Liquidator installed below pool level

[Miranda]

poolgirl and Bama,
How close is your equipment to the pool? Barnyard and I both have our equipment very close to the pool. In my case, this was the cause of poor flow problems in the original 1/4" installation (close proximity = too efficient = not enough head to create much vacuum on the suction side of the pump = low flow through liquidator tubing) so I wonder if this is somehow a factor in the check valve problems.

 

[Bama Rambler]

My pump and filter are about 15' from the closest pool wall.
The check valve is a 3/8" FNPT black from USplastic.
I just replaced the flow valve and tubing with super speedfit fittings (the same as Bruce & Sal sell) so I could get better control over the flow.
So far they're working great. It's much easier to adjust the new valve than the old one was.

One word of caution: If you order the speedfit fittings from USplastic be sure to get Polypropylene and not Acetal! Acetal isn't recommended for chlorinated water, even pool water is listed as not compatible.

 

[Guest]

Miranda,

The one thing that both you and Barnyard have in common is both of your returns from the LQ to the suction side are attached in a way that debris builds up and could be the culprit. Barnyard is moving his return to the original location, just prior to the inlet side of his pump instead of on the bottom of the basket. We are in the waiting mode...

 

[poolgirl22]

I've got about 10-12 feet from the inlet and skimmer to my equipment. My main drain line has about 30 feet of pipe between the drain and the pump. I've noticed I get much better pressure from the inlet when I'm on main only vs. skimmer only. As it is they're both wide open most of the time.

 

[barnyard]

Miranda,

The one thing that both you and Barnyard have in common is both of your returns from the LQ to the suction side are attached in a way that debris builds up and could be the culprit. Barnyard is moving his return to the original location, just prior to the inlet side of his pump instead of on the bottom of the basket. We are in the waiting mode...

I did move it last night. I lost a lot of flow on the LQ though. I also noticed something last night when I did it. My flowmeter had WS in it. I didn't notice it on Sunday night when I noticed the LQ overflowing. I had just cleaned and re-installed the LQ last Friday, and went through 2 check valves since then. I'm not sure how fast WS forms, but I am starting to suspect that might be a problem for me at least. But, good grief, it forms VERY fast if that is what it is. So, I acid washed the flowmeter and got my Ph down to below 7.5 and am going to run it when I am home with the old (maybe broken) check valve in it until I think I have gotten rid of the WS (if I can get rid of it). IF it is WS causing my valve failures, I only have 1 good one left, so I am trying to do everything I can before I sacrafice it.
Sal, I also want to stop by Home Depot or Lowe's to look into the other check valve we discussed. Maybe today I will have time. I'm starting to like that idea a little bit more everytime I think about it.
Miranda, that is an interesting observation about the closeness of the equipment to the pool. It does appear that mine is located much closer than Poolgirls or Bama's. Now, I just need to figure out why that would make a difference. :?:

 

[Miranda]

Miranda,

The one thing that both you and Barnyard have in common is both of your returns from the LQ to the suction side are attached in a way that debris builds up and could be the culprit. Barnyard is moving his return to the original location, just prior to the inlet side of his pump instead of on the bottom of the basket. We are in the waiting mode...

I'm not sure what you are referring to, if you could please explain further....I don't have any debris buildup. Everything is brand new (plumbing, liquidator parts) and I didn't have debris buildup with the old setup either.

 

[Guest]

Miranda,

The one thing that both you and Barnyard have in common is both of your returns from the LQ to the suction side are attached in a way that debris builds up and could be the culprit. Barnyard is moving his return to the original location, just prior to the inlet side of his pump instead of on the bottom of the basket. We are in the waiting mode...

I'm not sure what you are referring to, if you could please explain further....I don't have any debris buildup. Everything is brand new (plumbing, liquidator parts) and I didn't have debris buildup with the old setup either.

If you look at where your hose returns from the LQ to your "T", that is where sand and debris will settle and possibly causing that to check back to your valves and contaminating it.

 

[Miranda]

Miranda, that is an interesting observation about the closeness of the equipment to the pool. It does appear that mine is located much closer than Poolgirls or Bama's. Now, I just need to figure out why that would make a difference. :?:

You and I have very little suction on the Liquidator suction line. The reason for this is that the close proximity of the skimmer. Water flows very freely through the short, unrestricted section of pipe from the skimmer and the pump easily gets all the water it needs so very little suction is created in the line. Pull the tubing with the pump running and put your finger over the end. You will notice there is very little suction. This is why we have liquidator flow problems, and the reason flow improves when we add a restriction by choking the line down with a valve. When we deprive the pump of easy water, suction is created, increasing flow through the liquidator tubing.

Bama and poolgirl have 10+ feet of pipe between their skimmers and pumps. The head loss/frictional forces of the piping restricts the flow to the pump in the same way that our choke valves do, so there is suction in the skimmer line because the pump wants for more water than is being provided. When they put their fingers over the end of the tubing, there is much better suction.

How does this relate to the check valves? I'm thinking about pressure/suction fluctuations. Bama and Poolgirl have stronger suction in the first place to help keep the valve closed, preventing backflow. The extra 10' of pipe and water stabilize the system and act to buffer any sudden shifts or changes in pressure against the valve. For you and me, there isn't much suction to stabilize the system, the pipe runs are short and a bubble or temperature change can move through that short pipe and eliminate any suction, perhaps even create pressure and allow backflow. Not a great scientific theory, but its all I can come up currently.

 

[Miranda]

Miranda,

The one thing that both you and Barnyard have in common is both of your returns from the LQ to the suction side are attached in a way that debris builds up and could be the culprit. Barnyard is moving his return to the original location, just prior to the inlet side of his pump instead of on the bottom of the basket. We are in the waiting mode...

I'm not sure what you are referring to, if you could please explain further....I don't have any debris buildup. Everything is brand new (plumbing, liquidator parts) and I didn't have debris buildup with the old setup either.

If you look at where your hose returns from the LQ to your "T", that is where sand and debris will settle and possibly causing that to check back to your valves and contaminating it.

I would agree with you, except for the fact that this problem occurred immediately upon installation of two different brand new valves, and the valves still look perfectly pristine inside. I have never seen a speck of debris inside the valves or in the tubing.

The overflow problem is solved by a stronger spring (for both of us). This tells me that somehow, the system is producing a condition that causes the check valve to overcome the forces holding it closed, and allow backflow. If it was debris, the stronger spring would not fix it, debris would still contaminate the valve.

My previous installation followed your recommendation (hole drilled in the top of pipe) and it overflowed then too.

 

[Guest]

If you look at where your hose returns from the LQ to your "T", that is where sand and debris will settle and possibly causing that to check back to your valves and contaminating it.[/quote]
I would agree with you, except for the fact that this problem occurred immediately upon installation of two different brand new valves, and the valves still look perfectly pristine inside. I have never seen a speck of debris inside the valves or in the tubing.

The overflow problem is solved by a stronger spring (for both of us). This tells me that somehow, the system is producing a condition that causes the check valve to open and allow backflow. If it was debris, the stronger spring would not fix it, debris would still contaminate the valve.[/quote]

The check valves are rated at 140 PSI (Both gray and Push in type). We have installed these on LQ's where solar heating is present (Over 30 feet higher then LQ) and have had no issues. As I told Barnyard, you could go to home depot and purchase a 1/2" PVC check valve and try, these are rated over 200 psi I believe.

 

[Bama Rambler]

I am unbelieveably puzzled by this. I've been dealing with controlling flow all my professional career and have seen some weird things happen. I would try sticking two check valves in line with each other at this point just to see what would happen.

The PVC check valve might work but some of them have pretty high cracking pressures, so keep that in mind.

 

[barnyard]

I am unbelieveably puzzled by this. I've been dealing with controlling flow all my professional career and have seen some weird things happen.

I don't feel so bad now. I haven't been dealing with controlling flow. I am an electrical guy ....... Electricity makes more sense to me! Heck, right about now, nuclear physics make more sense to me than this does.

 

[Miranda]

I am unbelieveably puzzled by this. I've been dealing with controlling flow all my professional career and have seen some weird things happen. I would try sticking two check valves in line with each other at this point just to see what would happen.

Test in progress...Have installed the two US Plastics check valves in series, about 8" apart. Max flow is reduced a little, but still a decent 4.5. I also opened both valves and reinstalled original springs and put a thin film of plumbers silicone grease on the rubber seal. I left the zip tie tails on for good luck. I will report back after 24 hours.

 

[poolgirl22]

(psst...I haven't trimmed my zip tie tails on mine either...if bama can leave them there...so can I...)

 

[Txmat]

Barnyard & Miranda, I have been following your travels with interest as I would like to add the liquidator to my ABG pool setup provided it is not a hit or miss proposition as to whether it overflows or not. In reading the thread it seems you both have narrowed it down to a check valve problem. One fact that I am not clear on is the source of your check valves. Are they from the Manufacturer, Sal & Bruce, or some other source? The same question for those following this thread who have ABG setups and are not experiencing the check valve problem? There was earlier speculation that both of you had check valves from a bad batch. Has that been ruled out?

Larry

 

[Miranda]

Barnyard & Miranda, I have been following your travels with interest as I would like to add the liquidator to my ABG pool setup provided it is not a hit or miss proposition as to whether it overflows or not. In reading the thread it seems you both have narrowed it down to a check valve problem. One fact that I am not clear on is the source of your check valves. Are they from the Manufacturer, Sal & Bruce, or some other source? The same question for those following this thread who have ABG setups and are not experiencing the check valve problem? There was earlier speculation that both of you had check valves from a bad batch. Has that been ruled out?

Larry

Barnyard and I both had the overflow problem with the US Plastics valves recommended by Rabbit on his 3/8 conversion thread. I recall that many people did the upgrade according to Rabbit's instructions without problem, but I don't know how many have ABG pools. The bad batch theory has not yet been ruled out, but Barnyard has tried other valves, and I had the same problem with the OEM Hasa setup (but that was a long time ago and I no longer have the OEM valves to test and verify cause). The only people who have replied with ABG setups are Bama and poolgirl. Bama has the US Plastics valve and poolgirl has the Sal/Bruce valves (I think).

Barnyard and I have a similar setup and the same problem (checkvalve related overflow) but there are several differences between us. He has high CH, white stuff and his valves are obviously failing (you can blow through them both ways after a while) I have low CH, no white stuff and my valves test fine and seem to work fine, yet allow backflow intermittantly.

 

[Txmat]

Thanks Miranda, Has the stronger spring that I read about solved the back flow problem? I know it was reported that the stronger spring had slowed the flow rate so that it is not a long term solution.

 

[Miranda]

Thanks Miranda, Has the stronger spring that I read about solved the back flow problem? I know it was reported that the stronger spring had slowed the flow rate so that it is not a long term solution.

Yes. The stronger spring solved the overflow problems, but I have since switched back to the original spring because of the low flow.

 

[Guest]

I am also looking for other solutions...

 

[barnyard]

Barnyard & Miranda, I have been following your travels with interest as I would like to add the liquidator to my ABG pool setup provided it is not a hit or miss proposition as to whether it overflows or not. In reading the thread it seems you both have narrowed it down to a check valve problem. One fact that I am not clear on is the source of your check valves. Are they from the Manufacturer, Sal & Bruce, or some other source? The same question for those following this thread who have ABG setups and are not experiencing the check valve problem? There was earlier speculation that both of you had check valves from a bad batch. Has that been ruled out?

Larry

I have tried 3 different valves, with the same result. I wish mine and Miranda's symptoms were the same so we could proceed in a common direction to solve this. My valves actually fail and stay failed. I can clean them and they appear fine, but within a short period (hours not days) they fail again. Yes, I do have some WS, but it doesn't appear to affect the float valves which has me puzzled. It appears that the float valves should be more sensitive to WS than the check valves since they are sitting in it , and at least the out float valve passes just the same amount of water/chlorine/ws as the check valve, with what appears to be a smaller orifice. I'm in the process of trying to rid myself of WS, not sure how that will work out since reading through all the threads on WS there doesn't seem to be a concrete answer to why it forms to begin with. I really wish that others that have the LQ setup with ABG pools and equipment set ups such as me and Miranda would chime in with their experiences. I would think there would be someone out there that has at least tried it.