Sucking Air

[jmaff]

I have an inground pool with a Hayward C110 filter and a jandy valve that can adjust between the skimmer and vacuum. everything was fine until two weeks ago when I noticed air bleeding into the system (air was coming out the return vents). I narrowed it down to the vacuum side. When I use the Jandy valve to shut off the vacuum everything works fine. When I crack the valve open a little, I hear gurgling noises and start seeing air inside the screen basket of the filter. This then fills the filter canister with air. I bleed the system but it stills fill with air. When I shut the vacuum off the system returns to normal. I had a person check for leaks but he did not find any and told me this was normal( i tried telling him that I never experienced this before). I have noticed no drop in water level or any water discoloration (signs of a leak). I removed the vacuum hose from the hole in the side of the pool just to make sure there was a no leak with the vacuum components. Any suggestions?

 

[257WbyMag]

I'm still relatively newish here on TFP but I think that I have learned enough to take a stab at this.

If air is being pulled into the system, I would think that it would be unlikely that you would notice any water loss. Water levels falling would indicate a return side leak. Sounds like you have a suction side leak. Does the system lose prime when the pump is off or do you notice air entering the system only when the Jandy valve is routed to your cleaner? If you lose prime with the pump off, it could be your strainer basket lid (common). However, if it only seems to occur with the pump on and then only when you route the Jandy valve to your cleaner line, that could very well indicate that your Jandy valve is at fault (less common). You mentioned that you removed your cleaner from the wall to eliminate that possibility from the equation which is a good move. It's sounding to me like it is probably your Jandy valve but I would like to see what the experts say.

I had the same thing happen with mine last year. I replaced the insides of my Jandy valve and problem solved. It's a relatively easy fix if you have any DIY knowledge.

 

[waste]

Were you vacuuming large debris (especially acorns)? You may have an obstruction in the vac line which is causing cavitation. You can try turning off the pump, switching the valve to full vac, remove the pump lid and use a garden hose, with a rag wrapped around it to force the obstruction back out of the line (it'd be nice to have someone poolside to see if stuff starts coming out).

Just trying to give you another take on what might be going on.

 

[jmaff]

I have positively narrowed the problem to the vacuum part of the filter. I had the pipes pressured check for leaks (there was none). I used the garden hose but dont know if the pressure was enough to do anything significant. The pool is enclosed in a screen house so there is nothing large to worry about being sucked in.
The problem begins as soon as the valve is turn towards the vacuum (I'm talking just a crack open). I like the idea that the water is cavitating but cant believe that something can clog a 1.5" PVC tube after going through the Barracuda G3 vacuum head.

 

[mas985]

I don't think the problem is cavitation. The bubbles caused by cavitation will disappear right after the impeller, the collapse is what causes the damage, so this will not cause air in the return lines. Besides, it takes a near shut off in the suction line to cause caviation and it is quite loud.

The cause is likely a partial blockage in one of the suction lines. This causes high suction at the pump which in turn causes air to be sucked in through either a valve or the pump lid which is then passed on to the filter.

One thing to try is to run the vacuum without the head and hose. If there is no air in the pump basket or filter, the cause is likely in the vacuum hose or head. If there is air in the pump basket or filter, the cause is likely in the line running from the pool to the pump.

 

[jmaff]

I am still sucking air in through the vacuum branch of the filter system. I had the line tested for leaks and obstructions. There is nothing wrong with the line. I have removed the vacuum head and hose and still suck air. I can not run the vacuum as it is since the air eventually fills the filter housing thus preventing filtering and I also shoot a lot of air out the return vents.

 

[spishex]

So the air shows up as soon as you crack open the vacuum line, but there's absolutely, positively nothing wrong with the line?

Have you replaced/lubricated the lid o-ring and re-taped the drain plug in your strainer housing? What kind of pump is it?

 

[jmaff]

I had the gaskets replaced and lubricated. The only thing that is different with the system is that I replaced the pump motor in Nov. I had no problem with this set up until about three weeks ago. Is it possible that something happened with the motor (getting wet...) causing it to short out and pump more water than it can suck?

 

[spishex]

Probably nothing to do with the motor. Your water flow is limited by your impeller, so you'd have seen the most it can do when you replaced it.

If the line was pressure tested then I'd think it's gotta be an obstruction along the lines of what Mark mentioned. When you say it was tested for leaks AND obstructions, what was done to be sure there was no blockage?

Changing the gaskets wouldn't necessarily have fixed a problem at the male adapter or drain plug, but I'd expect both of them to leak at least a little bit during normal operation if they were the problem.

If you have a valve on the return side one thing you might try is partially closing it so the filter pressure increases by a few pounds (not too far), then turn off the pump and see if the back pressure causes a small squirt of water anywhere on the suction side, particularly around the lid, plug, adapter or valve.

 

[akenis]

I've got a very similar problem....SO FRUSTRATING!

When I crack the three way valve toward the suction line for my Baracuda (which is disconnected) I hear a swoosh (air/water mixture) and the basket level goes down, and the pump intermittently looses prime.

I spent several days trying to unplug what I thought was a clogged, but $100 to Roto Rooter, ran a snake clear through.

I tried the wet rag technique on the valves and fittings near the pump, didn't notice any sound or bubble change. Guy is coming tomorrow. Guess I'll get the lines pressure tested.

I'll try swapping the insides of my three way valve... I have one on my return side. I'll also try lubricating the basket and drain gaskets, but I don't see how that could be the problem as I can suck all day long from the skimmer.

Any other ideas before the pool guy gets here w/ a $125 minimum?

 

[akenis]

No luck here...

anyone ever see this stuff called fix a leak?

http://www.poolcenter.com/leak_detection.htm bottom of the page.


Is it possible that I have a partial blockage...even though roto rooter went clear through?

Air in the pump or blown into the pool

A pool leak in the suction side plumbing (from skimmers and main drains to equipment), may pull air into the plumbing lines that will show up in the pump or be blown back into the pool through the returns. Air leaks such as this can be just as damaging to your pool even though you may never notice symptoms of water loss. Evidence of air in the system can also be caused by a blockage or obstruction in the suction lines. Either situation will require professional attention to avoid causing mechanical damage to your pool equipment.

If so...where is the air coming from?

 

[jmaff]

akenis, this is what I am experiencing. When the vacuum line is deactivated the filter runs fine(no air), but when I open the valve I hear swooshing and air start coming in. In a short time the filter cartridge housing fills with air and I start pushing air out the return ports. The line was pressure tested for leaks(negative) and manually checked for obstructions (negative.) I have no visable signs of a leak (water level falling)
This just started one day after having no problems at all. I am totally dumbfounded by this.

 

[duraleigh]

Hi, jmaff,

I think this thread is suffering just a little from some terminology issues so let me ask you a few questions and see if we can't get your problem resolved.

You have the ability to select (with a jandy valve) the source of your water coming into the pump.......either from the skimmers or from the "vacuum". Can you select both at once or is it one or the other?

I am unclear about the "vacuum" line. Tell me where it's located within the pool. Is it a dedicated vacuum line? Is that what you use it for?....to vacuum the pool?

I think you've already answered these but please clarify just a little to make sure we're all on the same page. :lol:

 

[akenis]

Well... it could have been worse!

I had already started excavating to find the source of my leak, when a kid showed up from the pool co. He did everything I did over the previous couple of days. He also tried a drain king attached to a bottle of nitrogen. Nothing helped....

He was about to give up, but wanted to take my 3 way apart again. No problem there. Then, he finally looks back through the 3 way toward the union I installed on the vac line (3 in of pipe, an elbow, and another 2 in of pipe). Total blockage!!! Leaves wrapped around R2D2's severed arm.

yep a little kids toy.... 3 days of work, endless frustration, $100 for roto rooter, $85 for the pool guy, and a bunch of holes that needed to be filled in.

Still don't understand where all the air comes from when the source of water is limited? Like I said...it could have been a lot worse! I'm going to order the baracuda inline filter!

 

[mas985]

Still don't understand where all the air comes from when the source of water is limited?

From any part that you can take apart such as the pump lid and the valves. They both rely on seals to keep the air out but when there is a blockage, there is a pretty strong vacuum in the line. Especially in the pump basket where the vacuum is the lowest so this is the spot that most likely will leak air first.

 

[jmaff]

I have 2 pvc pipes that come from the pool to the filter. These pipes attach to a Jandy valve with a 3 way connections. Built into the side of the pool is a hole below water level where the automatic vacuum connects. One of the pipes comes from the skimmer and the other from the hole for the vacuum. The valves lets me have both pipes open, just the vacuum open or just the skimmer open. When I have the valve so just the skimmer is open, the filter operate properly. When I adjust the valve so the vacuum line is open, I start hearing a gurgling sound and air starts going into the pre filter screen housing (there is a clear coverto view). The vacuum operates but air starts filling the filter housing (which contains the filter cartridge). Eventually the filter housing is completly filled and bubbles start to come out the return ports into the pool. Looking into the pre filter housing I see a mixture of 50-50 water/air.

This happens even if the vacuum hose and head are not connected (there is nothing conected to the hole in the side of the pool) I had the pipes pressure tested and checked for obstructions and none were found.

 

[mas985]

Another possiblilty is that there is a leak in the vacuum pipe going from the pool to the 3-way valve. This will allow air to enter the pipe but only when the vacuum line is engaged. It could be anywhere along the line, including underground, although most likely at a fitting joint.

One way to tell if it is a leak or blockage is by the filter pressure at the various valve settings. If the filter pressure is about the same for either the vacuum only (open no hose or head) and the skimmer only, assuming the pipe size is the same, then it is probably a leak. However, if the pressure is a lot lower for the vacuum line alone, then it could still be blockage although I know you checked for that already.

 

[duraleigh]

jmaff,

Thanks. Very clear, now. mas985 has got the problem pretty narrowed down. Let us know what you find. :-D

 

[jmaff]

mas985 you hit the nail on the head. I suspected an air leak but was told there was none. Someone now agrees with me. What is happening is that the vacuum line sucks air in while engaged. When off since the pipe is at or above the water level there is no leaking. But now I recently had a leak develop around the light fixture.

Thank you everyone for your help. There are a lot of knowledgable people here and I appreciate the advise.

 

[mas985]

I'm glad you found the leak. Hopefully it won't be too difficult to fix.