Ho' lotta bubbles!

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J

Jeff Lebowski

Well-known member
May 29, 2014
86
Virginia Beach
Here's my dilemma/dilemna -

There is an excessive amount of air leaving the filter in my pool. I am not referring to the four corner jets, but rather the main exhaust flow from the filter. The large diameter hose which drives the pool vac vents a whole mess of air. It never did this in the past.

Thinking that I had a vacuum leak somewhere in the passive solar array on my roof, I checked ALL of the fittings. Yet, the bubbles persist.

They really mess up the buoyancy of the pool vac, so this is my primary complaint.

What's the best way to troubleshoot a vacuum leak like this?
 
I read the tutorial. Many thanks.

I ruled out the obvious. The strainer seal is tight with no issues. There is plenty of water in the pool so the skimmer is not sucking air. I can find zero "spit-back" when cycling the pump on and off.

That being said, there is a fair amount of silicone sealant around the inlet to the pump which leads me to believe that there were problems there in the past. But, there is ZERO air in my strainer basket as seen through the clear cover. Yet, a ton of air is coming out of the outlet into the pool.

Weird. I would think that I would see air in the strainer basket.

Is it possible for air to be drawn into the plumbing which delivers the water from the solar panels (2 stories up) to the pool? Or, is that side pressurized to a level which prevents it? Years ago I had a huge fish tank and we used to drill a small hole into the tube which spit delivered the water back to the tank, downstream of the pump and on the pressure side.

I am stumped.
 
I only found my leak by holding a hose with a nice flow (not a forceful one) over the little filter drain at the bottom, then filter lid, then closest pipe connection, then union...wait, all the air goes away. Theres your leak. Leave the water flowing there for 10-20 seconds and watch the filter for the air to go away. Put water on all the possible points of a leak and youll find it, if its above ground.
 
I'm afraid that I can't answer your question unless the valve(s) are on the roof. Each group of panels has (what I think is vacuum release) a valve at its end. I bought the house and pool used, so my knowledge is limited. I had a new roof installed two years ago and removed and reinstalled the passive solar system at that time. I spoke with the retailer and I do recall him speaking about orientation, etc for reinstall and I know that one end of the plumbing has a valve, which I believe is for vacuum release.

Do you think one has failed? I will call them and inquire if they know. They are not in the pool business, rather the solar business but they may know the answer.

Today I will shut the solar heat OFF in an attempt to isolate the problem. With shutoff valves I can take it completely out of the loop. If I still have bubbles with it OFF, I'll know its elsewhere. And if the bubbles disappear, I'll have my culprit.

Many thanks for all your input!
 
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OK....little research here.

When the solar collectors are off, the bubbles are gone. It takes a minute or two, but they go away completely. When selected back on, the bubbles return.

I spoke with a guy at the vendor and his suggestion was that I could change the location of the vacuum relief valves. I countered with, "well, I've lived with them like this for four years and this is the first they've bubbled".

His suggestion is that perhaps I have too much DE in my filter. He asked if I had recently backwashed (I had) and suggested that perhaps I put too much DE in the filter and that the differntial (psi and flow rate?) between the collectors and the filter was causing the relief valve to "suck".

I DO have DE sitting on the bottom of my pool. Not a ton, but it is what I think is DE. The water is crystal clear and a brush across the bottom with produe a swirl of light "smoke" which I believe is DE.

So, since the pool vac has been inop since its bouyancy went to golly (due to the bubbles), there is a fair amount of crud on the bottom (its been WINDY here and lots of tree crud has found a home in my pool). I am going to vacuum out the crud and break open the filter and take a look. My filter calls for about 7 scoops of DE. Roughly, what does that look like on the filter elements? 1/16"? 1/4"? It will be interesting to see what I have when I pull the top off.

Thanks again for any and all input.
 
If you have never torn down the DE filter, you will be in for a surprise at the mess you are going to find. Take a look at the DE Filter Cleaning Tutorial.

Is your pressure on the filter higher than it used to be? If not, then their argument does not make sense. It could just be that the VRV needs to be replaced or maybe there is a little debris stuck in them.

BTW, do not trust the "scoop" size. You should weigh out your DE. Also realize that after a backwash, you should not add the full amount of DE in, just add 80% or so. More info: Use and Care of DE Filters
 

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Filter was torn down and cleaned last fall at close. I will revisit the tutorial.

Pressure is slightly higher. Is the VRV the pressure gauge on top of the filter??

The pool was filthy this year at open and required several backwashes to keep it running properly. I suspect that I may have clogged it and will try and find out.
 
Today I tore down the Filter and cleaned it. Here's what I found...

The filter panels themselves did not appear to have an excessive amount of DE on them, perhaps 1/8 inch. I have seen a thicker coating on them at the end of the season, but perhaps that is due to particulates filtered out of the pool. ?? There was a LOT of DE clumped on TOP of the upper manifold and on top of the elements. What causes that?

The system blows out LESS air now, but there is still some evident.

Spoke with the solar peeps and got some suggestions to troubleshoot -

1. Run the filter in RECIRC. If the air disappears it's definitely a filter/plumbing leak.

2. SLIGHTLY close the return ball valve from the solar collectors. This MAY change the differential between the filter and the water flowing down from two levels up on the roof. Less differential MIGHT cause the vacuum relief valves to close and shut off the incoming air.

So, I will try these and if no luck, replace the 20-year-old vacuum valves in an attempt to troubleshoot the system.
 
1. I disagree. Running on recirc will allow higher flow rates and pressure at the panel which could be enough to close the VRV.

2. Maybe, but that is just making the system less efficient.

You could always remove the VRV and plug the holes temporarily to see if the bubbles go away. That would confirm or refute that the VRV are the problem.
 
I agree with you on both points because at this point I am just trying to troubleshoot the system and figure out where the fault lies. This is my fourth season with the pool, and I've never had this (air) problem.

I am fairly confident at this point that the problem is exclusively within the solar system. Hopefully its the vacuum valves, since they seem to be the most likely culprit and easiest thing to fix. I was on the roof three weeks ago when I opened the pool and went over every connection to ensure that they were all tight. One leaking hose had split so that was replaced. The valves didn't get a second glance since they are basically an inert suction device. But, my solar system is 20 years old, so anything is possible at this point.

Thanks for your input. I probably get a chance to change them till next week, but I will try and post the results for future TFP users.
 
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