Any (easy) way to try to determine where an air leak might be coming from?

anthonypool89

Gold Supporter
Aug 26, 2016
957
Berks County, PA
Been a problem, to varying degrees, for quite a few years - air bubbles coming out of the return lines. Particularly noticeable since opening the pool this year. Very weird stuff going on with my pressure though. Filter pressure psi is going DOWN instead of up - that's weird. And so, the pressure coming out of the return lines is really pretty significant right now - almost like when there are no grids in the tank. It's not blowing DE into the pool, it's all air bubbles. As I said, this is not a new situation and sometimes (with higher pressure on the gauge) there is no discernible air coming through at all as the amount of flow coming through the returns lessens - like especially right before the DE needs to be cleaned out and psi is way up. If I turn the diverter valve all the way to drain side instead of skim - the amount of air bubbles increases. So....a leak somewhere in the pressure-side plumbing? I don't usually see much air in the pump strainer, since otherwise that would moreso indicate suction side leakage. Any suggestions? It's no real big deal except that it puts so much excess foam into the pool.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
14,733
Pleasanton, CA
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
Do you have solar running during these anomalies? If there is no air in the pump basket, the only place air can enter a plumbing system on the return side with the pump running is the solar VRV. Sometimes it can also happen in the filter while it is off but that air will decrease in time with the pump running.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
14,733
Pleasanton, CA
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
VRV = vacuum release valve.

But if you don't have solar, then it is not a source.

So if the air bubbles out of the returns continue for more than say 10 minutes, then the issue must be on the suction side of the pump. If PSI is varying, then one possibility could be that the water level is too low and the skimmer is periodically sucking in air. You may just be looking at the pump basket at the wrong time. Also, decreasing filter pressure is an indication of water and air mixture which also indicates a suction side air leak. Most of the time an air leak is from the pump basket lid and/or drain plugs. The second most common source is due to water level and/or a stuck weir door. After that it gets a bit tricky to find so I would focus on those two possibilities first.

 

anthonypool89

Gold Supporter
Aug 26, 2016
957
Berks County, PA
Most of the time an air leak is from the pump basket lid and/or drain plugs.
Been thinking it's time for new gaskets - not that I'm seeing any direct evidence of cracks or worn places in the pump strainer gasket, but still, very likely might never notice an area that could be causing a slight leak. I have a new one so might as well put it on. Same for the small o-ring at the air valve on top of the filter tank. Certainly doesn't take much to create some air bubbles.
 

DeanP66

Well-known member
Mar 26, 2014
1,230
San Jose, CA
Try spraying some soapy water from a sprayer around the areas where the gaskets are. If there's a leak, you'll definitely notice the bubbles from the water getting sucked in to the valve or union or even any fittings.
 
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