Decrease pool flowrate

[FightingGobbler]

While cleaning pool this weekend, I noticed decreased flowrate.

I have a spillover spa. Normally, there is spillover even at lowest pump RPM setting (1000). Currently, at 1000 RPM, I have no spillover nor is there water at pool return jets.

At 1000, the pump is running, but its clear no or very little water is flowing through the pump basket and SWG appropriately cuts off. Again, all of this changed compared to normal.

When I turn it up to 1500, I get water going over spillover, water at return jets, and SWG turns back on.

Checked the troubleshooting page on this site. Regarding operating pressure, when filter is clean and pump is running at 2750, my pressure is 15 PSI. Today pressure was 15.5. Cleaned the filter and pump basket, pressure back to 1500, but still no flow at 1000 RPM.

I didn't see or feel anything at pump inlet and tried to shoot water back up suction line with hose. No improvement, though I'll admit I'm not terribly handy, and I'm not exactly sure of what I'm supposed to feel.

2 other observations...I do have air in pump basket at low RPM but resolves at high RPM. I checked O-ring, seems ok.

Also have solar heating system. Even when solar is off, I hear water flowing through the solar plumbing. Could there be a check-valve problem?

Any suggestions?

 

[Dirk]

Hmm, could be a malfunction of the solar valve (or mis-adjustment). When solar is off, there should be no flow through the panels. But if solar is used, and then the pump is turned off, the solar panels will drain for a while back through the pipes, and so you would hear that. But if it's flowing through the solar system when pump is on and solar is supposed to be off, then that's not right. And that could rob some of your flow from the spillover.

You might also only think you are hearing water through those pipes, and it's actually just the sound coming from the other pipes. Your solar plumbing should have a check valve, and those generally have a clear window, so that if water is actually flowing through the solar panels, you can see it.

Or you might have a clog somewhere. You need to be careful about trying to unclog that yourself if you're not sure about the technique. You could make the clog worse, or damage an underground pipe, which would be really bad. Might be time to call in a pro for that, maybe one that could also check your solar valve. And one that carries liability insurance, so that if he messes up your plumbing, he can make it right. Don't be shy about asking about his insurance before he goes to work. If he balks about it, he's not the right guy for the job.

 

[FightingGobbler]

Today, the solar was off. Had the pump running at 2750 RPM, dropped it to 750 and I could hear and feel water rushing down the solar pipes that come from the roof. Similarly, later in evening, I had the pump running at 1500 RPM. Again, when I turned pump off, I could feel and hear water rushing down solar pipes from roof.

There is a Jandy check valve between filter and actuator going to the roof. No other check valves that I can see. I attached a picture of the solar pipes.

Could there be a leak in the solar actuator? Pump can then push water to the roof but at low pump RPM there's not enough pressure head to circulate through the panels and get enough water back through SWG and to pool. Qualitatively, the flow rate seems normal when solar is running with RPM at 2000...though I don't have flow meter.

Also, I appreciate you validating my reluctance to fish around to aggressively to declog. Fortunately, I do have a pool guy (with liability insurance) I trust here in town.

 

[Dirk]

Could there be a leak in the solar actuator? Pump can then push water to the roof but at low pump RPM there's not enough pressure head to circulate through the panels and get enough water back through SWG and to pool. Qualitatively, the flow rate seems normal when solar is running with RPM at 2000...though I don't have flow meter.

Let's call it the solar valve. The actuator is the component that moves the valve. A leak? Well, it's actually supposed to leak, if you have the right valve, which would be a solar drain-down valve. With solar on, the water goes up the left side, down the right. When solar is off, but pump is still on, the water should remain in the solar panels, but not flow through them. Then, when the pump goes off, the water is supposed to drain down both sides, left and right. The right side has an obvious path, and the left side drains through the drain-down gizmo (the "leak") in the solar valve. That's how it's supposed to work.

But you're missing a check valve. There should be one in between the PVC ball valve and the tee, on the right side. That check valve allows water to come down off the roof, when the panels are either heating or draining. But it prevents water from flowing backwards, up the right side and through the panels, when solar is off but pump is on (just as you suspected). If the solar valve has a drain down, and I think it does, along with the missing check valve, that would allow water to run backwards through the panels, and that's what you hear draining back down when the pump is turned off, or turned down low enough. Here's a diagram that shows the missing check. You have the one on the blue pipe, you're missing the one on the red pipe:



It's an easy fix. It doesn't really matter if it's above or below that PVC ball valve. Buy one on Amazon, cut the pipe and glue it in, making sure to observe the direction of flow (look for the little arrows).

 

[Jimrahbe]

Gobbler,

If this were my pool, the first thing I would do is set both solar ball valves to off and confirm the your flow and spillover are back to normal..

This would confirm that the something in the solar system is the cause of your main problem.

You only have one check valve and it is designed to let water flow up and not down in your set up.. This means it can't be bad, as it can't "leak" in the open position..

If you turn both ball valves off and the problem goes away, then it pretty much has to be a bad solar valve. Not the actuator, but the valve itself.

Thanks,

Jim R.

 

[Richard320]

Poor flow can also come from a clogged pump impeller. Are there any pine trees around? Pine needles can slip right through the baskets.

 

[Dirk]

Gobbler,

If this were my pool, the first thing I would do is set both solar ball valves to off and confirm the your flow and spillover are back to normal..

This would confirm that the something in the solar system is the cause of your main problem.

You only have one check valve and it is designed to let water flow up and not down in your set up.. This means it can't be bad, as it can't "leak" in the open position..

If you turn both ball valves off and the problem goes away, then it pretty much has to be a bad solar valve. Not the actuator, but the valve itself.

Thanks,

Jim R.

WARNING, WARNING WILL ROBINSON! If he does that without understanding how the solar valve and its programming are working, he's going to dead-end his main pump. With both those valves closed, if the solar valve engages, the pressure from the pump will have no where to go.

If this were my pool (and this is how mine is plumbed), those two ball valves should first be removed (they're not doing anything of value, and just creating this potential danger), and the one on the right be replaced with a check valve (ideally a FlowVis if he wants to be able to optimize his solar panel heat efficiency). Then simply turning the solar valve to its "solar off" position will achieve the flow you're suggesting for the test. He needs to straighten out his solar plumbing anyway, and doing so first will be safest, and be a more valid test for the flow issue. It may even solve the flow issue, which is another reason to do the fix first.

 

[Dirk]

If you turn both ball valves off and the problem goes away, then it pretty much has to be a bad solar valve.

That might confirm that his incorrectly plumbed solar system is the cause, but it doesn't necessarily mean the valve is bad. Right now he's got water flowing up the wrong pipe, and until he fixes that, he can't properly troubleshoot his flow issue. You're right in that he can simulate the fix with the ball valves, but that's a risky approach, as per my post above.

 

[Jimrahbe]

Dirk,

Everyone has their own way to troubleshoot.. In this particular situation, I would want to make sure that the solar is the actual cause of the problem..

I am not quite the red lettering doom and gloom guy you are. If you shut off the solar ball valves all the water "should" go back to the pool.. If it does not, you have identified a problem that needs to be fixed.. As far as deadheading the pump, I'm not suggesting that he run things that way for other than a quick test.. I am not suggesting that he turn it on and go to lunch..

I see zero risk..

Thanks,

Jim R.

 

[Dirk]

He's got two issues, and one might be causing the other. Your troubleshooting MO will not reveal problem 1, and will in fact disguise it. The solar plumbing is plumbed incorrectly. That doesn't need to be diagnosed. It needs to be fixed, regardless of the flow issue. I was suggesting that since it does need to be fixed, he do that first. There is no option to skip that fix, whether he figures out the flow issue first or not at all, whether the solar is the culprit for the flow issue or not.

And, with all due respect, I'm not understanding why you're claiming zero risk. If his controller calls for solar heat while he has those two ball valves closed, he will deadhead his pump. And unless the OP knows exactly how to make sure that doesn't happen, then the risk exists, for however brief a time. You would know better than me what happens to plumbing or a pump or a filter should that occur, even briefly. If you're saying nothing bad will happen if the pump deadheads, then I would defer to your expertise: that the risk is zero.

If he fixes the plumbing as I suggest, he might fix the flow problem just by doing that. But he will definitely eliminate the risk. If the flow problem exists after the fix, then he can safely troubleshoot the system for the flow issue.

I've been wrong before, I'm happy to admit. And I chose the RED TEXT so that he wouldn't miss my theory, because I'm very confident about it. Of course, the OP can decide for himself which way to go, as he now has all the info, and two ways to solve this...

FG, to be clear, Jim is a TFP Expert and I am not. He has way more experience with pool plumbing than I do.

 

[FightingGobbler]

First off, thank you for the concise explanation and ensuing discussion. My pool learning never stops!

After reading this about 6 times, I think I've got it. One clarification regarding:

Then, when the pump goes off, the water is supposed to drain down both sides, left and right. The right side has an obvious path, and the left side drains through the drain-down gizmo (the "leak") in the solar valve.

So this means that when pump turns off, water from roof will flow down the right side to the pool as expected. Water will also flow retrograde down the left-side (the "up-pipe") and will be allowed to pass through the solar valve ("drain-down") into the right side PVC pipes and to the pool but will be prevented from going back to the filter by the check valve.

This solar was professionally installed about 4 years ago and we've had a few problems over that time. As such, I'm not surprised they didn't install both check valves. I'll start looking into getting the second valve installed, possibly by myself. *gasp*

Regarding the solar valve...in my picture above, the valve is currently "solar-off" and blocking flow up the left side to the solar and instead diverting flow back to the pool (and apparently up the right pipe given absence of check valve). Could the 3-way valve's "diversionary ability" be damaged...thus allowing some flow up the left side as well despite being in the "solar-off" position? Perhaps a failing gasket, etc. That could explain the sudden change. Understand that regardless of whether the solar valve is the culprit or not, I need to fix the plumbing issue.

If he does that without understanding how the solar valve and its programming are working, he's going to dead-end his main pump.

I have fiddled with those ball valves before...but always ensured that I manually turned the solar OFF at the electronic control first and confirmed that valve is bypassing solar. Nevertheless, I really appreciate the warning! I wonder what the weakest link is if I did go to lunch....the pump or one of the joints?

Thank you again for all your suggestions and illumination. I have few action items here. I'll post a conclusion once I reach it.

 

[FightingGobbler]

Poor flow can also come from a clogged pump impeller. Are there any pine trees around? Pine needles can slip right through the baskets.

I read about crud at the impeller potentially causing decreased flow. I couldn't feel anything at the inlet to the pump but I didn't disassemble it. No pine needles around but we did have the pool deck pressure washed 6 weeks ago. Maybe some of that debris (all small debris because pool is screened) got through pump basket but didn't get through impeller to filter. Timing seems off though...I imagine flow differences would have been immediately noticeable.

Fortunately, our trusted pool guy is coming to do some unrelated electrical work and he'll check the pump more carefully.

 

[Dirk]

So this means that when pump turns off, water from roof will flow down the right side to the pool as expected. Water will also flow retrograde down the left-side (the "up-pipe") and will be allowed to pass through the solar valve ("drain-down") into the right side PVC pipes and to the pool but will be prevented from going back to the filter by the check valve.

That is exactly right. And if your panels are arranged similarly to the little diagram I posted, you can see that most of the water up on the roof comes down the left side (the up pipe). All the panels drain down into the lower manifold, and then down the left side. Pretty much only what is in the pipe on the right, all the way to the top of the panels, comes down the right side.

Now this is assuming you actually have a drain down solar three-way valve. If it was professionally installed, that is what you likely have. Though that logic doesn't explain why they left off that check valve.

This solar was professionally installed about 4 years ago and we've had a few problems over that time. As such, I'm not surprised they didn't install both check valves. I'll start looking into getting the second valve installed, possibly by myself. *gasp*

Regarding the solar valve...in my picture above, the valve is currently "solar-off" and blocking flow up the left side to the solar and instead diverting flow back to the pool (and apparently up the right pipe given absence of check valve).

Exactly right. Two for two!

Could the 3-way valve's "diversionary ability" be damaged...thus allowing some flow up the left side as well despite being in the "solar-off" position? Perhaps a failing gasket, etc. That could explain the sudden change.

When you install the missing check, it will have a clear section (just like the one you have now). That will block any water going up the right side, which means there should be no water in the solar system if the solar valve is "solar off." If the three-way solar valve is not functioning correctly, and allowing water up the left side when it's not supposed to, then you'll see water coming down the right side, through the new checks "looking glass." That will answer that question.

Understand that regardless of whether the solar valve is the culprit or not, I need to fix the plumbing issue.

And that's three for three!

 

[Dirk]

There is another possibility, for your list of things to check (for the flow issue). Somewhere in your system you're supposed to have a VRV (vacuum relief valve). You can see it in the diagram. It can be just about anywhere along the solar plumbing. It's supposed to be above 6' from the ground. They are often placed on the roof somewhere. As you can imagine, when the pump is off and the solar is draining, there has to be a way in for the air that displaces the water. That's the function of the VRV. Otherwise the weight of the water would create such a vacuum that it could damage the solar panels, even the PVC pipe (hence: "vacuum relief"). Now a VRV is only supposed to let air in, not water or air out. It's got some sort of one-way valve mechanism, that's probably got o-rings or something pliable. And if it's on the roof, in the sun, it's eventually going to fail. So if it's leaking the wrong way, that would cause a pressure drop in your plumbing and impact flow. Once the VRV let out all the air in the pipes, you'd see water coming out of it, wherever it is. If it's working, it won't allow air or water out, only air in.

 

[Dirk]

I wonder what the weakest link is if I did go to lunch....the pump or one of the joints?

Depends on how well all the gluing was done! I would think an o-ring somewhere could blow (that's what happens with over-pressured scuba tanks: pop-hisssssssssssssss). The filter would be vulnerable too, I imagine. It has a very large o-ring. And because of its size I expect the housing could crack. You wouldn't want to be around, whatever gives.

Some (all?) pumps have safety shutoffs, so maybe the pump would just shut down. I don't actually know...

@mas985, if you deadhead a pool pump, say somewhere between the filter and the heater, what would give first? Would it shut down, burn out, or blow something up? Would it take a few minutes? Or a few seconds?

 

[FightingGobbler]

Just wanted to follow up on this thread...everything checked out with the pump. Nothing at the impeller. Still having the decreased flow issue, so I suspect its something with solar. Hopefully, I can get this checked in the next week.