Water seeping from water feature sheer descents

[welmis]

We have a water feature with two sheer descents controlled by an actuator. Even after the sheers run for as little as 3 minutes and then stop, water continues sipping from one of the sheers for many days (6 to be exact), even if I keep the feature off for all that time. Interestingly enough, the other sheer does not do it. After 6 days (if I do not run the feature) water stops but then it starts doing the same thing again as soon as I turn the feature on and then off. My contractor is telling me this is “pressure equalization” and nothing can be done about it. I do not buy this for the following reasons:
1. Why does it happen to only one sheer and not both of them?
2. Taking 6 days for water to get out of the pipe seems way too long for me.
3. Our lot is flat, so there is really no condition for gravity to play such a dramatic role.

Any thoughts/recommendations on how to troubleshoot/fix this?

 

[PoolGate]

Do they all come from the same pipe? Depending on how your pipe is graded going to the sheers, it could be angled in such a way that water remains and trickles out. This would effect primarily the first sheer. It is also possible that the valve going to the sheers is not set to close all the way and/or it is leaking a bit. Can you post a pic of it when it is off?

 

[ajw22]

Welcome to TFP.

Sounds like the diverter is not sealing closed 100%.

What model diverter and actuator?

 

[welmis]

Thanks @PoolGate and @ajw22. I am attaching the pictures as requested. You can see the exact actuator model there as well. Please let me know what can be done to fix this.

 

[welmis]

To add to my previous post, there is one pump (no dedicated pump for sheers). After the diverter with the actuator (on the posted pictures) there is a fork with separate pipe going to each sheer. There is an individual valve on each of the two pipes, but they are always open.

 

[mknauss]

Run the shears. Turn them off and close both of the individual valves. Does that stop the drainage?

 

[welmis]

@mknauss, thank you for your response. The test you recommended (turn the individual valves off) was recently conducted. While the sheer that has no issues never seeped water, it took 5 days for water to stop coming out from the other one.

 

[PoolGate]

It sounds like a vacuum is being created when the water to the sheers turns off and the remaining water in the pipes (downstream of the valve) is taking a long time to seep out of the pipes. I agree with your builder, I don't think you can do much about it. You could test this theory by running the sheers, turning the sheers off, turning the pump off, removing the pump lid, then turning on the sheers again (without the pump). If the theory "holds water" then you should see water drain out of the sheer.

 

[welmis]

@PoolGate, thank you very much for your assessment. We do not have a separate pump for the sheers (it is just one pump for both the pool and sheers), but we will try what you suggest. This being said, could you please clarify the following, based on your theory?
1. Why is vacuum created in the first place? Is it something related to how plumbing was done? Could this have been avoided?
2. Why is vacuum created only in one pipe (for one sheer) and not the other?

Really appreciate any thoughts and advise.

 

[PoolGate]

@PoolGate, thank you very much for your assessment. We do not have a separate pump for the sheers (it is just one pump for both the pool and sheers), but we will try what you suggest. This being said, could you please clarify the following, based on your theory?
1. Why is vacuum created in the first place? Is it something related to how plumbing was done? Could this have been avoided?
2. Why is vacuum created only in one pipe (for one sheer) and not the other?

Really appreciate any thoughts and advise.

Think of a straw with water in it that you hold your finger over the end. Same concept.

Is the sheer that this happens with the first sheer in a series of sheers? If so, it happens for this one because the pressure isn't enough to get to the next sheer. It is just dripping.

If someone suspected this could happen, I suppose they could arrange the pipe so that it isn't possible for water to drip out. For instance, have the pipe start low and then come up before connecting to the sheers.

I think it would be harder to create the vacuum on purpose if you wanted it. You wouldn't, but due to a series of how that pipe runs, the vacuum forms.

 

[welmis]

@PoolGate,
Your Question: Is the sheer that this happens with the first sheer in a series of sheers?

Answer: As you can see on the attached pictures, each sheer has its own individual pipe that goes from the equipment panel. The split happens right there.

So based on your theory, if the plumbing is modified in such a way that right after the diverter they do a V-shape split turned upside down (i.e. the pipe after the diverter goes down and then gets split into two pipes, each going to its sheer (as opposed to water going to the first sheer pipe and then the second one), may this issue be remediated?

Thanks a lot.

 

[PoolGate]

@PoolGate,
Your Question: Is the sheer that this happens with the first sheer in a series of sheers?

Answer: As you can see on the attached pictures, each sheer has its own individual pipe that goes from the equipment panel. The split happens right there.

So based on your theory, if the plumbing is modified in such a way that right after the diverter they do a V-shape split turned upside down (i.e. the pipe after the diverter goes down and then gets split into two pipes, each going to its sheer (as opposed to water going to the first sheer pipe and then the second one), may this issue be remediated?

Thanks a lot.

I think right before the pipe hits the sheer it needs to have that bend in it. Think of the straw example again. If you turned that straw upside down so the opening is facing up, vacuum or not, it isn't going to dribble.

Did you do the pump off, top opened test? That should relieve any vacuum and prove, or disprove, the theory.