How to Identify and Correct Air Leaks

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If you see many 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
  • leaks in the pump seals
The leak source must be identified and corrected for the most efficient pool pump operation.

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 many 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 gulp air with the ebb and flow of circulating water.This simple problem has a simple fix:
  1. Add water.
  2. Drop in a hose and get that water level up.
  3. Keep an eye on it in the future to prevent a reoccurrence.
A simple add-on feature is water levelers, ensuring your water is always optimal.

Step 3

Before we begin inspecting 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. An air relief is generally only found on Cartridge and DE filters. Sand filters do not have this feature, so expect some to splash when accessing plumbing elements like the pump strainer lid and unions.

Step 4

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

Check the rubber gasket for cracks, pinching it 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 the 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, allowing 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

Another common culprit is PVC plumbing glued joints like tees, elbows, and valve ports. The epoxy sealing these joints can become brittle and wash out over time, allowing air leaks that prevent the removal of all the air from the pump, leading to priming failure. This can create a progressively worse and worse air leak. The suction hose plays a crucial role in the priming process, and leaks in connections can prevent the vacuum necessary for drawing liquid up the suction hose to the pump, further complicating priming efforts.

The smoke, soapy water, or shaving cream method is the standard way of finding these leaks, and 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 may be pinhole-sized leaks in one or multiple hose sections. To find and replace these hose sections:
  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
Complete this for each hose section; replace the sections with holes.After checking the hose sections, consider performing a 'bucket test' to determine if your pool is losing water due to leaks or simply through evaporation. This simple method involves filling a bucket with pool water, marking the water levels inside the bucket and in the pool, and then comparing the two after a few days. If the pool water level drops more than the water inside the bucket, it's likely you're losing water due to a leak rather than evaporation. This test is great at helping identify whether you have a pool leak or if it is natural evaporation.

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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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(561 to 600 of 604)

 Posted: 5/26/2012 

Does anyone know a whirpool forms by the skimmer of your pool?
 Reply

InyoPools Product Specialist  Posted: 5/24/2012 

andyash - If you haven't replaced your sand in the last 5 years, I would do that. Also check to make sure that your impeller is not clogged with debris.
 Reply

 Posted: 5/23/2012 

I have opened my pool recently and my pump is recurclating water back into the pool but it appears weaker than the previous year. I have checked the pipes/backet and sand filter however there does not appear to be a blockage...HELP!!!
 Reply

InyoPools Product Specialist  Posted: 5/22/2012 

drew4602 - Unfortunately, you are at the point where you may have to have a pool professional come in and check you underground pipe. They should have the equipment to isolate your problem
 Reply

 Posted: 5/22/2012 

I have a ton of air coming into the pump to the point where it completly loses prime in a day or so. I replaced every gasket, o-ring ,seal, checked the unions and it's still happening. i believe there is a leak in the suction pipe underground. The problem is how to isolate it and find out where. There are two drains inside the pool, one in the deep end and one in the shallow end. There are also to skimmers, and it's all piped into one flex pipe coming out of the ground with no valves to speak of. PLEASE HELP!!
 Reply

InyoPools Product Specialist  Posted: 5/21/2012 

Will - You may have to hire a pool professional to check your underground pipes for you
 Reply

InyoPools Product Specialist  Posted: 5/20/2012 

Tina – If your pump housing has a large crack in it, it will suck in air through that crack. You should stop using that pump and replace it. It is not safe.
 Reply

 Posted: 5/19/2012 

I do have a lot of air bubbles coming into the pool. The housing has a large crack in it. Could that be the cause?
 Reply

 Posted: 5/18/2012 

Hello - It appears I have some sort of leak. I have the pentair whisperflow pool pump and every morning when I wake up, the water level in the basket is basically gone and when I start the filter, it takes a while for the system to draw the water back up from the pool ( inground pool and pump is about 2 feet above pool level). Any suggestions on how I can identify where the leak is? I do not see any water around the pool pump area
Thanks
Will

 Reply

InyoPools Product Specialist  Posted: 5/11/2012 

Dave,
I don't know how you are using the floc clarifier but here are some guidelines: The floc needs to be added slowly the pool. The filter needs to set to recirculate on a sand or de filter. After circulating for approx. 5 hours, the customer can turn the pump and filter off for 24-48 hours to let everything settle. Once that time has passed, they will need to vacuum everything that settles to waste. If the pool is really cloudy they may need to repeat the process.

 Reply

 Posted: 5/10/2012 

My pool won't get clear, chemicals are perfect tried floc clarifier, everything. It will not clear up what should I do?
 Reply

InyoPools Product Specialist  Posted: 5/8/2012 

patrick,
I have used standard schedule 40 PVC (Lowes) pipe on many of my pool fixes and have had no problems. Make sure it's Sch 40 pipe and not the thinner drain pipe.

 Reply

 Posted: 5/8/2012 

Hi,

It appears that I have an air leak at the suction intake line right before the pump strainer basket. I am planning on sawing the pipes and replacing them. It's about 6 inches long. The intake line has '1 1/2' on the side and the top pipe says '2"' on it, so I was assuming they are standard PVC pipe sizes I could get at Lowe's. However, I went to Lowe's and the guy there said that PVC pipes don't fit in pool pumps because the pool companies deliberately make them like an eighth of inch different so they can charge more for replacement parts. Is this true? Or can I buy normal PVC piping? I have a Pentair Challenger 3/4 HP pump, and the manual says the hole is a standard 2" so I have no idea what to believe. Thanks!

 Reply

InyoPools Product Specialist  Posted: 4/25/2012 

mrmonk - If you had flow in the backwash before your changes, I will assume that your multiport valve is good since you didn't do anything to the valve. If you have no or little flow in your system in any valve mode (filter, rinse, etc) you probably don't have prime and have an air leak on the suction side. Check any gaskets or 0-rings that were involved in the change to confirm that they are set properly. If some are old or look cracked, replace them. Put a small amount of lubricant on them to help the seal.
 Reply

 Posted: 4/24/2012 

i have just put a new moror nad basket on my pool and changed the sand why am i not getting any water in the back wash
 Reply

 Posted: 2/29/2012 

Any advice for getting air in the lines only when the pump and filter are off? i somehow lose prime after the system shuts off, regain prime about 30 seconds into the pump/filter turning on again.
 Reply

InyoPools Product Specialist  Posted: 1/15/2012 

If your problem was with the main drain you were loosing pressure on the suction (input) side of the pump. To monitor this side you might install a flow meter before the pump to see any change in pressure. By alternately shutting off your suction lines (main drain, skimmer, and cleaner suction lines) you could see which line might also have problems. See "flow meters" on our site. Select the right meter for your size PVC pipe.
 Reply

Anonymous  Posted: 1/15/2012 

when the pool is full the main drain looses pressure at thepump and water volume ,air is entering return line . i have the pool drained now and pressure tested the main drain line and is holding pressure so far. what else can i do ?
 Reply

InyoPools Product Specialist  Posted: 10/21/2011 

Ben – When you first run your cleaner, air sometimes gets trapped in the cleaning housing or the hose. You might need to twist the cleaner back and forth when you first place the cleaner under water to get the air out. Also completely submerge the hose with one end up to purge the air out of the hose before connecting it to the suction port.
 Reply

 Posted: 10/20/2011 

I have air-bubbles coming in when i connect my cleaner, but there are no holes in the hose (as i have used a number of different ones) and there are no bubbles when cleaner is not connected. Any ideas??
 Reply

InyoPools Product Specialist  Posted: 9/29/2011 

Harley - Sounds like you've checked all the easy places. You may have a leak in one of your suctions lines underground, and at this point, you may need to have a pool professional look at your pool.
 Reply

 Posted: 9/26/2011 

Inground pool and having cavitation @ pump&motor, air in return to pool pulse with return water and when backwash. Changed sand, checked suction line no leaks, no apparent leaks on pump. Could this be behind impeller or what? checked lid & gasket on pump nothing obiovus looks good.
 Reply

InyoPools Product Specialist  Posted: 9/24/2011 

Frank - The size of your pump should be based on what it takes to turn over all the water in your pool in 8 hours. Assuming that your pump was sized correctly you need to run it 8 hours a day in the summer to filter out impurities and keep it in balance regardless of actual use. In the winter when the temperature in cooler, you can cut back to 6 hours.
 Reply

 Posted: 9/24/2011 

How long shoud I run my pool pump daily if the pool in not being used and it is in balance ?
 Reply

InyoPools Product Specialist  Posted: 9/11/2011 

Tony, It is not uncommon to have some air visible in your system, like a large bubble at the top of your pump strainer basket. As long as you pump maintains prime and your pool water is flowing you should be OK.
 Reply

 Posted: 9/8/2011 

i have air showing in filter dome but pump shows no air coming into system?
 Reply

InyoPools Product Specialist  Posted: 9/8/2011 

rina - Your pump may not have enough HP to add on the pool cleaner. If you have valves to control the flow of water to the pump, try shutting down the main drain or your skimmer line when you want to use your pool cleaner.
 Reply

 Posted: 9/7/2011 

Why does my pump loose pressure every time I connect the automatic pool cleaner and then it would not have enough pressure for the cleaner to operate
 Reply

InyoPools Product Specialist  Posted: 8/27/2011 

Sounds like you might be having a problem with your start capacitor. Look at our How To Guide on Replacing a Pool Pump Capacitor under "Pumps". If not you may have more serious problems in the windings of your mortor.
 Reply

Anonymous  Posted: 8/26/2011 

My pump dies not come on everyday. Sometimes it turns on for seven days in a row and other times it may turn on for two or three days and then trip the breaker in the electric box. It hums for a few seconds when you reset the breaker and will trip again if you do not turn it on and off several times while trying to get the pump working. Pump was new three years ago. Any suggestions?
 Reply

InyoPools Product Specialist  Posted: 8/7/2011 

Check to make sure that O-ring between the tank body and filter head has no tears and is set properly. Older O-rings tend to stretch and sometime bulge causing an air leak. If you haven't replaced this O-ring recently, condsider replacing it.
 Reply

 Posted: 8/7/2011 

I just cleaned the grids on my DE filter. Since I put it back together,I have to prime it every day to get it to operate. It takes a while, then starts to pump,but there is gurgling noise coming from the filter, like sucking air. Any suggestions?
 Reply

InyoPools Product Specialist  Posted: 7/11/2011 

If you are getting any water to your waterfall, your pump is probably primed. It is more likely that you have a clog somewhere. You will probably have to have a pool professional come out and look at your pool to resolve this problem.
 Reply

 Posted: 7/2/2011 

I'm frustrated..... I've been trying to get a good prime,but to no avail. I just had a new motor put on and since then I cannot get a good prime, I've replaced o-rings on the filter,pump lid.put a new relief valve on the filter.I have hardly any water coming over my waterfall from the spa, so that tells me I'm NOT getting a good prime or there could be a clogg,that's another question, how do you get rid of a clogg? HHEELLPP Me....
 Reply

 Posted: 6/6/2011 

When I turn off the power to my above ground pool the water in the skimmer shoots up like a geyser and turns over the skimmer basket.It also seems to raise up on my motor skimmer top and water sprays out. I have air bubbles coming into the pool when I first start it up also.
 Reply

 Posted: 5/28/2011 

While my pump was operating it was sounding like it was sucking air and air bubbles were comin out into the pool. Water was leaking from the strainer lid. I repalced the o-ring and water was still leaking from the lid. I continued to let the pump run and it finally started operating close to normal and water quit leaking. and now its like the pump is not sucking enough water into the strainer and the psi stays at 10. not sure what the problem is . hope i didnt burn the pump up. can someone please help?
 Reply

 Posted: 4/23/2011 

when i adjust three way to full open on skimmer (suction side), I get fluctuating pressure from 0 to about 5 PSI. In any other position I have no pressure issues. Baskets are clean, I've used a drain king unsuccesfully and tried compressed air (around 20 PSI). I suspect a clog or a leak in the skimmer plumbing line. What's the best way to determine this?
 Reply

 Posted: 4/10/2011 

I have pockets of air coming out of my returns. There are no airbubbles in the strainer. On my sand filter The clear top will have air in it and I will bleed it off then it comes and goes. Please HELP
 Reply

 Posted: 4/8/2011 

When I replace the DE, the filter starts and gains correct pressure, then I add the slurry into the skimmer, all is well. But when I put the cleaning hose of my manual pole cleaner into the skimmer hole to do some cleaning, the filter pressure drops to Zero and wont budge--the suction disappears. Water level is o.k. --when I finally get it to run again--it spits DE into the pool. What gives?
 Reply

Anonymous  Posted: 4/3/2011 

Do pool pumps lose suction as they increase in age? I do not have any air coming in from the suction side.
 Reply