Air in Pool Pump or Bubbles in the Pool

air in pool, bubbles in poolAt the beginning of every pool season, a regular question we hear at the In The Swim Call Center is “Why are air bubbles blowing in my pool?” or another popular problem – “My pump won’t catch prime!” The answer is easy for both; there is air in the pool pump.

In front of the pump, specifically – is where the air is getting in. Before the pump impeller is what is called the “suction side”, and a void will leak air when the pump is on. After the impeller, on the out going side of the pump, is called the “pressure side”. Any leak on the pressure side will leak water when the pump is on, while a leak on the suction side will suck air into the system.

Check to see if you have air in the pool filter. You would do this by opening the air bleeder valve on your filter. This will allow all air in the pool filter to blow out. You will know when all of the air is out because the valve will be lightly spritzing water all over you! Simply tighten it back up to close the air bleeder.

Here are a couple of easy remedies to try before calling in some high cost pool contractors to locate air in the pool pump.

water-1Water Level: Is the water level too low in the pool, allowing air to get in the skimmer? If so, please add more water to your pool. This can damage your pool equipment if proper water levels are not maintained. You want to make sure the water covers at least half way up the skimmer opening. The skimmer weir should be in place, and should not be stuck in an up position, or blocked with pool toys.

water-2Strainer Pot Lid: Turn off the pump and take the lid off and inspect it. Was it screwed on properly in the first place? Is the o-ring seated in its ridge on the pump lid properly? Is the o-ring clean and lubricated? If not take the o-ring off and clean it off with a dry rag. Place it back on the lid, seated in its ridge, and then apply pool o-ring lube.

water-3Unions & Valves: Check any unions or valves that you have hooked up before the pump. To inspect a union fitting you will need to turn the pump off. Remove the nut and inspect the o-ring. If you can see it when you remove the nut, it has moved out of place. Clean it; re-seat it in its groove and lube it. Be careful when tightening the nut, that you don’t move it out of its place. For valves before the pump, inspect they are tightly screwed in using Teflon tape around any threaded valves to ensure no air is getting in that way.

Loosewater-4 Incoming Pipe: Coming into the pump, this threaded fitting can shrink with heat and lose tightness. Pool putty can be a temporary repair, around the area where it screws into the pump, or the threaded fitting can be re-sealed, or replaced if the threads look melted and shrunken. To replace this fitting, you’ll need to cut the pipe if you don’t have a union installed. Use Teflon tape and silicone for a good seal, and tighten it securely.

water-5Drain Plugs: The drain plugs on some pool pumps have o-rings. These pumps can leak air from the front drain plug, if missing the o-ring. In fact, any pump can leak air through the drain plug if they are loose, or if Teflon tape is not used on the threads.

tips for pools using baquacilIf these five tests didn’t show you where the pump is drawing in air, here’s a little tip you can try. If you can get your pump running at “full head”, really pumping water, the test is to shut off the pump while looking closely at the area in front of the pump. Look for a very short spritz of water to shoot out at the exact moment that the pump shuts off. Sometimes it’s only a drip, but enough to help you locate the source of the air leak on your pool pump.

bubbles-in-pumpIf that still hasn’t helped you find out where the pump is drawing in air, you may have “deeper” issues, possibly underground. But, almost always you’ll find that air in the pool pump is a much simpler problem to fix.

You can always call our tech support line, at 800-288-7946, we can walk with you through these steps to help you diagnose the problem of air bubbles in the pool, or air in the pool pump.

Sheryl Sollis
InTheSwim Staff Blogger


Air in Pool Pump or Bubbles in the Pool — 7 Comments

  1. What if the bubbles comes out only when you turn the valve partially to suck air from the main drain and from the skimmer but it does not happen when you close the skimmer valve

    • Ah good question, if you close one line completely and the air stops, you may deduce that air is coming from that line, or that valve. Jandy type valves can draw air in around the handle stem, two small orings are used, under the cover, and it also has a larger cover oring that can fail. Sometimes just the lid is loose, or tightening the knob will stop the air. If you have union valves (Hayward), there is an oring around the valve body, and internal seals on some models, and also handle stem orings. You can pressurize a line using a drain king on a garden hose, to see where a leak occurs, or use shaving cream to see where it sucks in. The most common air leak on systems is not the valves, but the threaded fitting that screws into the pump, second most common is loose pump lid, or unlubed or damaged pump lid oring. But when it leaks air only on a certain valve setting, you may be onto something – but usually, closing one incoming line makes the pump suck harder, or work harder and cavitate, which leads to more air being pulled in, thru the tiny voids.

    • Hi Tonya, the air will just come out of the return closest to the pump usually, it’s too lazy to travel all the way to the others, which are all part of the same pipe.

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  3. Hey, regarding Tip #5… can the drain plug actually draw in air and NOT be leaking water at the same time. I have no signs of water drips; wouldn’t that be the tell-tale sign? Thanks.

    • Yes – the drain plug can draw air in, and not be leaking, at the same time. If the drain plug drips water when the pump is off, it is sucking in air when the pump is on. But if your drain plugs are not dripping when the pump is off, your air leak is likely not there.

      Most pump air leaks occur on the threaded fitting that screws into the pump. The threads can shrink with high heat, allowing air to be drawn in. Pool Putty can be used as a temporary, but long lasting repair, but the correct repair is to cut-out and replace the PVC fitting, (usually a male threaded adapter, 1.5″ or 2″), using thread sealant when installing.

      For pump drain plugs, apply Teflon tape around the threads, first removing any old tapes or sealant. Many drain plugs also use a small o-ring, which can be necessary to replace every 5-10 years.

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