Air bubbles do not cease when the solar is on

[Magnew]

I joined this forum just to ask this question on this topic. My first post!

I just replaced my ancient 1.5 hp pump with a half horse pump (Pentair Challenger High Flow). Everything runs to exactly the specs that were predicted, i.e. flow rates, amperage draw! I'm quite please except for one thing. With the old mega pump, when the solar system first kicked on, it would purge air through the lines for about a minute, and then it would be clear and run with water only coming through the pipes.

Now, with the smaller pump and reduced flow, the air bubbles do not cease when the solar is on. While the initial "blow out" of air subsides, there is still a small stream of bubbles and an occasional burp of air. My theory is that the vacuum break is not seeing enough pressure to keep it sealed? It is mounted on the top pipe.

My "repair theory" is to remove the vacuum break on the header pipe, and replace it on the lower pipe?

Would this solve my problem satisfactorily? Are there any other considerations or solutions that I should think about? (Other than adding back a larger pump, lol!)

Thanks for your help,
Mike

 

[mas985]

Re: Solar Panels and Vacuum Breakers

Welcome to the forum!

What you are suggesting might fix the problem but it is worth trying to find the cause and see if there is a simpler solution.

Most pumps should have enough head to keep the vacuum release close including yours but it will depend on the setup. So first a couple of questions:

1 - Confirm Pump Model# - CHII-NI-1/2FE

2 - Approximate height of the vacuum release valve relative to the filter gauge.

3 - Clean filter pressure when solar is running and when it is not.

4 - Is there a check valve after the filter and before the solar panels? If so, what kind is it (e.g. flapper, axial spring load)

5 - Suction/return plumbing description. Number of pipe runs from/to the equipment to/from the pool, distance between equipment and pool, pipe diameter, number of skimmers/main drains, number of return eyeballs.

 

[Magnew]

Re: Solar Panels and Vacuum Breakers

Awesome! Thanks Mark!

1. Pump model number is CFII-NI- 1/2F

2. Vacuum release is approximately 15' higher than pressure gauge at filter

3. Clean filter pressure solar on is 13, solar off is 10. (Suction gauge is set to 10 inches solar off, drops to about 8 solar on.)

4. There is a 1/2 lb spring check valve after the filter, and also on the solar return line.

5. All plumbing is 1.5 inch, distance to pool is about 25 feet, 1 skimmer and drain line each join thru Jandy valve before pump, one vacuum line joins this manifold via a Jandy valve; return is thru two lines thru another Jandy valve...one line is via 4 eyeballs in pool, and one via eyeball in spa (waterfall feature).

The pool is 9100 gallons.

Thanks so much for the help!
Mike

PS: Another idea I had which may help efficiency but may not help this problem is to pipe everything on the suction side from the jandy valves to the pump in 2 inch. Theory being that the suction side has basically three one and a half inch lines feeding the pump via Jandy valves. If a picture would help let me know!

 

[bobby1017]

.

Now, with the smaller pump and reduced flow, the air bubbles do not cease when the solar is on. While the initial "blow out" of air subsides, there is still a small stream of bubbles and an occasional burp of air. My theory is that the vacuum break is not seeing enough pressure to keep it sealed? It is mounted on the top pipe.

Mike

I think your right, I was told that if the flow was insuficient the "vacuum break" could allow air to be drawn in. With a variable speed pump the solution was to increase the rpms, not sure if you have a single speed.

 

[Magnew]

[attachment=0:vpcfk3i5]New pump (Small).JPG[/attachment:vpcfk3i5]And here is a photo of my pad...

 

[mas985]

Re: Solar Panels and Vacuum Breakers

Given your setup, it should work just fine except that the solar PSI rise is lower that what I would expect. Is the solar valve sending ALL of the water to the panels or is some of it being bypassed around the panels? If so, you may need to adjust the cam in the solar valve to send more of the flow to the panels.

BTW, what is configuration of the panels? Number of panels, size of each panel, etc.

I just noticed one more thing, some of the suction ports are shut off or nearly shut off, what happens when you turn them all on?

 

[Magnew]

Correction: clean filter PSI solar on is 15, off is 10

I am not certain if the solar valve is sending all of the water to the panels. I'm not aware of how to test for that, except to disassemble the valve and look at the cam?

The solar panels are 4 x 12 I believe, and I have seven of them.

Interesting, when I turn all the suction ports wide open, with solar on, I have more bubbles. When I turn off one of the return lines (to the spa), there is only a slight reduction in bubbles (I thought the back pressure increase would affect the vacuum valve on the solar, but maybe not).

Thank you, everyone, for all the help and suggestions. I will keep at it until something works!

Mike

 

[mas985]

I am not certain if the solar valve is sending all of the water to the panels. I'm not aware of how to test for that, except to disassemble the valve and look at the cam?

Watch the valve handle when solar is on vs off. With solar on, the handle should be pointed upwards. If it is tilted slightly, there is some water that is getting bypassed.

Interesting, when I turn all the suction ports wide open, with solar on, I have more bubbles. When I turn off one of the return lines (to the spa), there is only a slight reduction in bubbles (I thought the back pressure increase would affect the vacuum valve on the solar, but maybe not).

Does the filter pressure increase when they are all open?

Does the air out of the returns stop completely when solar is off?

Does the pump basket have any air? If so, there could also be an air leak on the suction side as well.

 

[Magnew]

I did not notice a filter pressure increase when all the suction lines were opened (I'll have to recheck).

Yes, the air out of the returns stop completely when the solar is off.

But that was not the case yesterday. I am indeed still chasing down a leak on the suction side, as there is air in the pump basket. However there are now no bubbles from the returns unless the solar is on. I will be replumbing the suction side this afternoon to completely stop that leak.

 

[mas985]

The air leak could be from either union or the pump basket lid. Try using some pool lube to seal those two connections. It might save you some trouble.

Also what about the solar valve position?

 

[Magnew]

I used the lube on both the basket o-ring as well as the union o-ring. I also took every off on the suction side and re-did the plumbing, i.e. lots more teflon tape and dope. Eliminated the air seen in the basket, which was fairly significant before.

The solar valve is straight up at the 90 degree position when the solar is on, so I believe the solar panels are getting all the water in the flow.

However, with all that, I still have bubbles with the solar on.

What is my next step? Replace the vacuum breaker, and put it on the lower pipe instead?

Thanks for everything,
Mike

 

[mas985]

If just the VRV was bad it would leak water out not air in so I don't think that is the problem. Your system should work fine with the VRV at the top of the panels. The height should not be a problem. I also have a 1/2 HP pump and am running solar on a two story roof.

Since you have eliminated all of the air in pump, the only place where it could be entering the system is the VRV. But since the filter pressure is 15 PSI and a 15' rise is only a loss of 6.5 PSI, that means that there is a 8.5 PSI (20' head) loss between the filter and the VRV which would be a lot for your plumbing set up. It could be the check valve between the filter and the solar. Spring check valves tend to have pretty high head loss. Given that you are also interested in efficiency, that might be a good thing to replace anyway. The Jandy or Pentair flapper type of check valves have a lot less head loss.

 

[Magnew]

Thanks, Mark. Sad for me, that check valve is brand new!

 

[Magnew]

I am curious...is the vacuum breaker a valve that is "normally open" or "normally closed"?

 

[mas985]

Without pressure, it is normally open. When there is pressure, the valve closes. If the valve is broken and it doesn't close, water will come out. In some cases such as yours, there is a slight negative pressure at the VRV so air is sucked in. Dropping the VRV down in elevation will probably stop the air from getting sucked in but it really won't address the true problem which is too much head loss in the lines.

BTW, do you have a model # for the check valve that you are using and where did you get it?

 

[Magnew]

It is the FloControl True Union Spring Check Valve 1700 Series w/ 1/2 lb spring, and I bought it at Solar Direct.

 

[mas985]

I am little surprised that they sell that kind of valve although a 1/2 lbs spring is not too bad. Is this the same check valve that is at the return side of the solar?

Another simple way to confirm that it is the VRV, is to plug up 3 of your 4 returns so all of the return water will come out of only one return. When the filter pressure rises and the bubbles dissapear, then the problem is for sure that the pressure at the VRV is too low.

Also, you don't happen to have a vacuum gauge to measure the suction at the pump? I just wanted to confirm the operating point of the pump.

 

[Magnew]

Any suggestions on how to plug three of the return lines?

I had a suction gauge on before, and had everything set for 10 inches without solar on. I took it off
When i was chasing down the suction side leaks. I'll have to reinstall it.

I really appreciate all this!

 

[mas985]

Hold the corner of a wet rag and twist it into a cone shape and stuff it into the hole. It doesn't need to be perfect, it only needs to stay in with the pump running.

Also, about how far above water level is the pad level?

 

[Magnew]

The pad is at or below the water level of the pool.

I've had an interesting afternoon and have many things to report:

1. I reinstalled the pressure gauge, and also redid the solar sensor which I had in the non-basket port on the pump. The suction leak is back, but I moved on to other things and have not fixed it yet, mostly because everything I tried did not work.

2. I dialed everything in the best I could--the cleaner was moving around OK, and the weir door was pulling down some. With this, the suction was 7 inches and the filter psi was 15.

3. I spent a lot of time with maximum pressure to try to pull all the air out of the lines, dealing with the suction side leak. I believe I overheated the pump as it shut down, and was able to be turned back on after a 15 minute cool-down period. Not sure if I should be worried about that. It seems to be running fine now.

4. Looks like the maximum suction I can get is about 12 inches. Not sure if this is meaningful.

5. I went ahead and moved the vacuum breaker from the top header to the lower pipe. With solar on, the bubbles did not cease but they were noticeably smaller/less. This is with the solar panels totally in the shade and cold.

6. I hadn't done the rags yet (in the three outlets), but I did turn off the one eye feeding the spa/waterfall. Even less bubbles!

7. Then I opened all the valves on the suction side (full flow from skimmer/drain/vacuum), and the bubbles completely stopped!

Now I have two issues unresolved: the dang suction leaks, and wondering if my pump is underpowered for what I need it to do!

Thanks,
Mike

PS: I could not read the mfg of the check valve from the solar, other than it was a two inch union spring check valve. This is what was already there--I did not replace it and it is a different valve than the new one post-filter. I've attached a photo of it.