How to Determine and Correct Air Leaks

This guide covers how you should identify and correct air leaks. 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.

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 pum

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.

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.

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.

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.

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.

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.

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

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.

If you have any other questions about pool and spa products please do let us know - we are here to help! 

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