Low flow from returns, alot of air


In The Industry
Jul 3, 2013
This is a customer's pool. There is very little flow from their returns, but there is a ton of air from them. They have a Hayward Super Pump 1. Water is very turbulent in the pump basket. When I use a water hose to apply water at the front of the pump where the suction pipe attaches, the turbulence goes away. Can this air leak be enough to cause so much loss of flow through the returns? I have used a hose bladder in the pump basket to shoot water to both skimmers separately. There doesn't seem to be any blockages there.

If the air leak at the union at the front of the pump is indeed the only culprit, as you can see in the attached picture, there is nowhere to easily cut and attach new pipe and union. I could cut at the front of the valves where the pipes come out of the ground but I'm trying to avoid that. Would I be able to use a fernco 2" x 1.5" coupling over the existing "T" to a piece of 1.5" pipe?

What about silicone around the union at the front of the pump? Is there anything I could use to seal around the union while leaving the plumbing in place for now?



Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
Bedford, TX

The most likely problem is the square pump lid O-Ring... Have you installed a new one? Is the lid tight?

As a temp fix I would try the silicone around the pump input pipe.. Right where it screws into the pump.

When it does get fixed, I recommend using pump unions and you won't have these problems... :mrgreen:


Jim R.


Silver Supporter
In The Industry
Aug 15, 2017
Spring Valley, NY
I would say try to seal the pump housing drain plug near the floor. That may be the culprit as it gets removed every winterizing and the put back for the swim season. It has a "O" ring there and they don't always seat right once it gets pinched. Many PBS use silicone from the get go on those.


In The Industry
Apr 1, 2018
Bangor Maine
I would almost bet the mpt at the suction end is the issue. What have you tried to locate the air leak?

A fernco fitting is tacky and temporary. Cut out the problem and replumb.