How to Identify and Correct Air Leaks

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If you are seeing a significant number of bubbles coming out of your return lines into the pool, you probably have an air leak in your filtration system. Possible sources of this problem are low pool water levels, leaks around the strainer lid, leaks in the unions or leaks in the pump seals. For optimum pool pump operation, the source of the leak must be identified and corrected.

Video

Step by Step

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Step 1

Your swimming pool filtration system has two sections: the suction side (from the pool to the pump) and the discharge side (from the pump to the pool). Check the strainer pot of your pump. If you see a significant number of air bubbles moving through the strainer pot, you know that the air leak is somewhere on the suction side of the system plumbing before or at the pump.

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Step 2

The ideal water level should be at least halfway up the skimmer intake. If the water level drops below that level, the skimmer can start to gulp air with the ebb and flow of circulating water.

This simple problem has a simple fix: add water. Drop in a hose, and get that water level up. Keep an eye on it in the future to prevent a reoccurrence. A simple add-on feature is water levelers, that make sure your water is always at optimal levels.

Step 3

Before we begin the actual inspection of the plumbing elements. Switch off the master breaker to your pool pump.

Release water pressure in the system using the air relief valve on your filter. The air relief is generally only found on Cartridge and De filters. Sand filters do not have this feature, so expect some splashing when accessing plumbing elements like the pump strainer lid, and unions.

Step 4

Pool Pump Strainer Lid O-ring; The pump strainer lid is sealed by a single gasket; which once it loses pliability can provide a direct route to foul your prime. Normal signs of wear are cracking in the rubber, warping or stretching, and the obvious, missing bits

Check the rubber gasket for cracks pinching the gasket into a smaller loop. Cracks will look like striations across the length of the gasket.

Warped or stretched gaskets are evident when the o-ring sits in the groove o-ring, spilling over. The warping of an o-ring can lead to it being pinched creating a gap through which air can enter the plumbing.

If necessary, replace with new gasket, after cleaning the o-ring’s groove of gunk and leftover lube. Apply a new coat of lube, as well.

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Step 5

Your pump housing’s drain plugs are often overlooked when diagnosing an air leak, but these little gasket-sealed ports cause havoc if the seal is broken. Use any of the air leak techniques mentioned above or do an eye inspection for a pinched or defective gasket.

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Step 6

If your pump strainer gasket wasn’t the issue, move forward to the pump union. Most pumps have a union on their intake, this allows for easy maintenance and removal. These unions have a single gasket that seals the cuff and screw on adapter. Most commonly these o-rings become pinched. Go through the checks of the o-ring mentioned in the previous step

Step 7

PVC plumbing glued joints like tees, elbows, and valve ports are another common culprit. The epoxy sealing these joints can become brittle and washout overtime. This can create a progressively worse and worse air leak leading to complete pump priming failure.

The smoke, soapy water, or shaving cream method is the standard way of finding these leaks. Repair can be as simple as adding a caulk patch. Or if you want to ensure a permanent fix, re-piping and gluing will be necessary.

Step 8

If your air leak problem only occurs when you attach your vacuum hose, then the issue maybe pinhole-sized leaks in one or multiple hose sections. To find and replace these hose section:
  1. Disconnect all hose sections
  2. Use tape or plugs to seal the end of each section
  3. Submerge the hose section, while looking for any stray air bubbles coming from the body of the hose
  4. Complete this for each hose section, replace the sections with holes
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Step 9

If you still have a significant number of air bubbles coming out of your return lines into your swimming pool, you may have a bigger problem like leaks in your underground lines. Call a pool maintenance professional to help you isolate your problem.

Comments

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(321 to 360 of 604)

InyoPools Product Specialist  Posted: 6/13/2016 

Nick - See our guide on "How To Prevent DE Filter Powder Returning to Pool" for possible causes and solutions of DE going into the pool.
 Reply

InyoPools Product Specialist  Posted: 6/13/2016 

mpives58 - You still may be getting air sucked into your system on the suction side of your pump. A couple of thoughts. Did the tradesmen work near any of the underground suction pipes (assuming you have an in-ground pool)? Could they have loosened one of the joints? Thought two. Do you still have bubbles, if your run without the cleaner vacuum plate installed - e.g. without using the cleaner? If not, you may have a leak in one of the cleaner hoses or the plate. Is the plate completely under water? To test for a leaking hose, try holding all the hoses under water when the cleaner is operating.
 Reply

 Posted: 6/12/2016 

Great site guys! I have a Pentair diverter to allow my inground pool to filer via the skimmer or the drain or both. When it is filtering via the drain, skimmer or both there are no issues. Only when I attempt to vacuum via the skimmer air is introduced into the pump and I loose suction. Any suggestions?
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 Posted: 6/11/2016 

Hen my filter turns off de is backing up into pool by main drain
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 Posted: 6/10/2016 

I have had problem with air bubbles seen at pool pump basket for a little while. It seems to coincide with tradesmen work recently done where localised excavation and fencing was done. I had a pool man come and check the system and he changed pump suction O Rings and e pump basket O Ring seals. He said the problem was better but I still see a big drop in water level in pump basket when cleaner is fitted and air in the top of basket. Recently another pool man came and checked and said the automatic valve in line with cleaner hose and skimmer box vacuum plate was sticking shut causing too much suction at cleaner head. Once this was unstuck the cleaner works better but there is still air at the pump basket but not as much. I spoke to the pool man and asked him if I have an air leak anywhere and he said the pump may be cavitating but I don't understand what this means. I have spent money trying to fix a problem but am getting confused by the outcomes so far. What can I do?
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InyoPools Product Specialist  Posted: 6/6/2016 

jeff - Check your new gasket and lid first. I always go back to my last repair to resolve a problem. Then here's a link to our guide on "How to Correct Low Water Pressure in Your Pool System". It may help resolve your problem. Check for a clogged impeller first. That is a common problem with low water pressure.
 Reply

 Posted: 6/4/2016 

replaced lid and gasket on hayward superpump after an hour or so air bubble shoes up and skimmer suction drastically decreases as does return output
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InyoPools Product Specialist  Posted: 6/2/2016 

Frustrated in KS - Is this an in-ground or an above ground pool. If in-ground, did you buy an above ground pool pump instead of an in-ground pump? An AG pump has to be installed below the pool to have gravity dump water into the pump. It cannot suck water up above the pool to prime the pump.
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 Posted: 6/2/2016 

Had to replace the pump since the old one decided it wasn't going to work when we started opening the pool. Put everything back together and now can't get it to prime. Tried all the troubleshooting techniques mentioned and can't find a leak. Could it be the pump?
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InyoPools Product Specialist  Posted: 6/1/2016 

Brian - It is normal in most pool systems for some of the water to drain back into the pool when the pump is shut off. It normally takes 1-2 minutes for the pump to prime when it is restarted.
 Reply

InyoPools Product Specialist  Posted: 5/31/2016 

Denise – You may have low water flow due to a clogged pump impeller. See our guide on "How To Clean Out a Pool Pump Impeller".
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InyoPools Product Specialist  Posted: 5/31/2016 

tired of failure - You are right. Air would not be coming in from the broken filter gauge. It would be squirting water. Check for the obvious suction side air leaks listed in this guide.
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 Posted: 5/31/2016 

I noticed that when my pump is off that air gets into my motor basket and the motor loses its prime. Does this mean there is a leak somewhere?
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 Posted: 5/31/2016 

When I start my pool pump after its been off for a while I notice that the water level in the pool motor is low and no longer primed. does this mean I have a leak somewhere?
Thanks!

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 Posted: 5/30/2016 

Please tell me what I should do. Inground pool with 3 jets, and air is coming out of only 1 jet. The basket near the filter shows no air bubbles at all. When the pump is turned off, I completely lose prime. Same happens after backwashing. To get the system to fill up, I have to dump a bucket of water into the basket near the filter and then clamp down the top. What do you recommend? Thank you so much
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 Posted: 5/30/2016 

My pump box is pulling in a lot of air. I noticed the sand filter gage is broken. Can this cause air to be pulled in to the pump box or would it have to be on the other side of the pump?
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InyoPools Product Specialist  Posted: 5/30/2016 

Randy – Sounds like you have most of the bases covered. I’d return back to the original inground suction leak to see if the repair has broken loose.
 Reply

InyoPools Product Specialist  Posted: 5/30/2016 

Low water at skimmer – I think you are seeing the air bubble that had collected in the system when the water was low. They should be reduced significantly after the pump has run about 5 minutes.
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 Posted: 5/25/2016 

First off I want to say thank you for this wonderful site. So I recently had a leak detection company come out and fix an inground suction leak. The pool is working great for a few weeks but then I noticed a lot of air bubbles in the return line and in the pump basket. I replace the pump lid over ring and the plug O-rings and I do not have any unions or diverter valves before the pump. If I prime the pump and turn it off it stays primed and never loses water. But when the pump turns on even on the lowest speed it starts drawing air bubbles. Any help would be greatly appreciated thank you.
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Anonymous  Posted: 5/25/2016 

the water got a little too low into my skimmer, now i have airbubbles coming out of the return. i have filled the water back up to the optimimum level how do i fix the airbubbles now?
I read nothing on this anywhere....do I turn off the pump? it should be a simple solution

 Reply

InyoPools Product Specialist  Posted: 5/24/2016 

confused - It sounds like you may have a blockage in the system. Some of the most common: a clogged impeller in the pump, a toy that has passed through the skimmer when you were cleaning out the basket and is stuck in the first elbow underground, a "clean" cartridge filter clogged with oils and chemicals, and a sand filter with clogged/broken laterals or standpipe. See our how to guides to correct these problems.
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 Posted: 5/23/2016 

I have very low pressure coming out of my jet. i replaced the pump but same thing. There are no air bubbles coming out of the jet? no leaks as far as I can see.
could there be a critter in one of the lines?.....i need help here!!

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InyoPools Product Specialist  Posted: 5/18/2016 

Fulk - Sounds like you may have several problems. If you are losing prime when the vacuum is running, you may have an air leak in the vacuum hose. Try holding all of the hose under water. If that stops your pump losing prime, you probably have a broken connection in one of the hose connections. Then pull the motor out of the pump to check for debris inside the pump. Also, replace the motor's capacitor. That may solve your startup issue. We have how-to guides on all these procedures. Just type in "how to" and the information you are looking for, into our search field.
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 Posted: 5/17/2016 

We have bubbles coming from the return jets and you can see air/bubbles thru the lid of the hair trap when the water is circulating. The pressure on the filter gauge flucuates from 0 -10. If we plug in the va uum hose we lose all pressure and prime, both. We have changed the O rings on both lids, checked the other O rings ( 2 small ones still need replaced)and unions, tried your technique for cleaning the impeller, got nothing but can not pinpoint the issue. The pump is old (we just bought the house) and hums when you turn it on so we have to twist the shaft to help it start and while it runs the vacuum seems to fade from strong to weak or like it pulses..We have not checked the shaft seal, difuser or taken out the impeller to check..any suggestions? The previous owners did switch from a sand filter yo a cartridge one and disconnected or capped the main drain so that isnt an option.....Help!
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InyoPools Product Specialist  Posted: 5/16/2016 

Cecilia - I can not tell what's going on here. I would need more information. Please call our service reps at 877-372-6038 for additional help. If you'd like to talk to someone in Spanish, ask for Hector.
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 Posted: 5/11/2016 

HELP! I have the automatic vacuum cleaner in my pool. Every time when the filter is on (5 hours per day), the vacuum will be cleaning the bottom of the pool automatically. For the past week or so, every time, when the filter turns on, I noticed the basket linked to the vacuum cleaner is popping up above the water. (It should be under water). And I can hear there is air leak. The basket usually fills up with water, but when the filter is on, the basket becomes empty. Since my pool automatically adjusts water level, water has been leaking as long as the filter is on. Would you be able to help and let me know what exact I should do? Is there a leak on the vacuum itself? Do I must have the vacuum in order to have the pool function properly? I have pool guy coming every week, I was thinking if the leak is from the vacuum or anything attached to it, I may just remove the vacuum altogether. Suggestions? Thanks a lot!
 Reply

InyoPools Product Specialist  Posted: 5/11/2016 

Hank - You may well have a leak in the pipes coming back from the main drain. During the winter, the ground can shift around the pipes and if the joints are not solid, one of them may separate. You will probably have to have a professional come in to look at your underground pipes.
 Reply

 Posted: 5/11/2016 

I am getting a lot of air in my system, but no air when I turn off the main drain and just circulate from the skimmer.
Is this the serious leak in the underground main line problem? Is this caused by incorrect winterizing? I live in MA.
Thanks

 Reply

InyoPools Product Specialist  Posted: 5/10/2016 

Very low pressure - If the water is just dripping slowly out of the discharge end of the pump, that probably is not your problem. Try removing your filter cartridge and running it without a filter. If that dramatically improves your flow, you need a new cartridge. Cartridges that are clogged with oil and chemicals may look clean but aren't. If you have a sand filter, try running in "recirculate" mode to bypass the filter. If that helps, replace the sand. If your filter is good, you may have a suction leak somewhere in the front end of the pump. May be causing backpressure in the filter.
 Reply

Anonymous  Posted: 5/9/2016 

I have air bubbles in my discharge side. The port that runs my pool vacuum/sweeper (Polaris) becomes VERY low pressure and won't run my sweeper. If I plug the port with my finger and let pressure build up I get big air pockets and bursts through the port. The pressure will stay god for a little while and then I have to repeat the process because the outward pressure becomes low again. On my discharge side pump there is a white PVC that comes out of the top of my pump at the end, I can see water around the neck where the pump ends and the pipe starts. Could this be the problem?
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 Posted: 5/7/2016 

The pop up head on the top step of our pool is creating a whirlpool and air is being sucked into the system. Any idea what is wrong and how I can stop this? It's very noisy!
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 Posted: 5/1/2016 

I had this problem once and ended having a very small crack in the lid over the filter basket.I replaced the lid and all was well.
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InyoPools Product Specialist  Posted: 4/25/2016 

Luiz - With all that debris you may have a clogged impeller. See our guide on "How To Clean Out a Pool Pump Impeller".
 Reply

 Posted: 4/22/2016 

Hi,
I have a jandy 2 speed pump. It had been running normal until 2 days ago. Pool had turned green, i used the leaf master and then brushed the pool. It got late and instead of running the filter and picking up all debris I decided to shut system off and wait until next day to open and clean the filter and then run it. Since then, I have not been able to get any suction in my pump. I've replaced the oring on the pump lid, checked valves to be open. I used a pressure bladder from the pump back to pool and it takes all the water, but then put buckets in pump and try to prime with no luck. Can it be that all 3 lines (2 from skimmers and main drain) got clogged at the same time? How do I know if the pump is just not sucking?
Thanks,

 Reply

InyoPools Product Specialist  Posted: 4/22/2016 

Perry - Sounds like your possible air leaks are in the suction side pool piping. Check for air leaks around all unions or other connectors between the pool and the pump. Also check the O-rings in the stems of the pool diverter valves. Check the connection at the bottom of the skimmer. This sometimes separates with the shifting of the pool over time.
 Reply

 Posted: 4/20/2016 

I continue to have air getting into the pool after I have replaced all of my gaskets on valves in the suction side of the pool. I have also done a check by shutting off the valves to the main line and the skimmer lines to see if I could isolate the issue that way and the bubbles are still there. When I change from pool to Spa Mode the bubbles go away (there is an automatic valve that shuts off flow from the pool so the water circulates only in the spa). When I return back to the pool mode they come back after a delay of 5 to 10 minutes. I don't understand what can cause the air to enter into the line after a delay. I have a Jandy SHPF pump and Jandy never lube valves. Any ideas would be appreciated.
 Reply

InyoPools Product Specialist  Posted: 4/5/2016 

Avilasx5 - It sounds like your system is generating backpressure. You may have too much DE in your filter or your filter's breather tube may be blocked. See our blog on "How Do I Correct Low Water Pressure" Go to the second part on "Causes of Low Water Flow Due to High System Pressure".



 Reply

 Posted: 4/5/2016 

Pool equip Sta-Rite S8D110 DE filter filters replaced 3yrs ago
Pump-Hayward SP2302VSP just purchased, it replaced a 1.5hp maxiglas2.
Filters have been cleaned. New kreepy krauly replaced a G4.
Vac runs for about 10-15 min moving along fine then slows to a crawl then stops. Pressure when running fine @ 12psi on gauge, then 20 when vac stops. I then backflush filter and while backflushing vac takes off running again. Any help would be greatly appreciated thanks

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InyoPools Product Specialist  Posted: 3/14/2016 

Peterh - If your sand filter has a breather tube going from the top of the tank to the bottom, it may be clogged causing air pressure to back up in the top of the filter. See out guide on "How to Reduce High Pressure in Your Pool System" to correct this possible issue and explore others related high pressure problems.
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 Posted: 3/12/2016 

I have a waterco pump and sand filter every time the pump switches off it blows the water our of the filter, pump and lines back to the skimmer box. It evens blows the skimmer basket out of its position. If I backwash and rinse it is good for one operation cycle then goes back to the same issue. When the pump re-starts it takes a long time to get water into the pump & filter system and it blows heaps of bubbles into the pool. Have checked all external connections without digging up piping so far. Any suggestions would be appreciated
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