Suction-Side Air Leak? A Plea For Help!

[HikeAbout]

Hello TFP! My husband and I just bought a new house with a 20-year-old in-ground concrete pool. It has two skimmers, two jets, and no main drain. The pump and filter are both below grade (in our basement). The pump is a Hayward Super Pump and it connects to a sand filter. We're pool beginners but we think we've got a pretty decent grasp now on how the system is supposed to work.

When we had a guy from the local pool company come out to teach us how to open the pool, he ran into some issues he didn't know how to fix. The pump basket won't stay more than half-way full of water (even when we fill it entirely to begin with). Also, the pressure is not constant, it's more like a heartbeat.

Here's what we're seeing at the pump:

Outside, one of the return jets (closest to the pump) is shooting out water and bubbles, again cyclically like a heartbeat. The other return jet (furthest from the pump) is shooting out only a very small amount of water. The skimmer closest to the pump is sucking pretty well, but the skimmer furthest from the pump is barely doing anything that we can tell. We haven't noticed that the water level of the pool has decreased at all in the last week.

We tried filling the pump basket entirely with water, but when the pump was turned on it went right back to what you see in the video. We checked that the weirs are moving freely. We replaced the pump basket gasket. We also tried backwashing the filter multiple times. We tried putting it into recirculation mode and bypassing the filter. Still no change. We tried plugging the skimmers, one at a time, to increase suction at the opposite skimmer. When we did this, the problematic skimmer increased suction somewhat but still didn't seem like it was at full power. We tried looking for air leaks around the suction-side of the pump (using shaving cream around all joints/fittings/seals) and didn't see any indication of a leak there.

If anyone can help us fix this.... we might name our firstborn child after you.

 

[1poolman1]

If the equipment is below the pool and the pump won't fill, there is a blockage in the suction line. Is there a valve in front of the pump that may be slightly closed?

 

[sktn77a]

Are you getting air sucked into either of the skimmers? That's often the cause of the pulsing pressure/bubbles.

 

[HikeAbout]

If the equipment is below the pool and the pump won't fill, there is a blockage in the suction line. Is there a valve in front of the pump that may be slightly closed?

There is a valve on the suction line and we have ensured that it moves freely and is in the open position. We are assuming there is some problem (either a crack in the plumbing or blockage) between the two skimmers since there is such a different in suction between the two but we aren't sure how to begin troubleshooting this.

Are you getting air sucked into either of the skimmers? That's often the cause of the pulsing pressure/bubbles.

No, both skimmers are getting only water, no air.

 

[jeffchap]

Did you check around the lid of the pre-filter basket. This should have been the first thing a pool tech would have checked, but who knows. 9 times out of 10, this is the source of a suction side leak.

Make sure the o-ring doesn't have any nicks or creases in it and is seated properly when you put the lid back on. Get some pool lube and apply liberally. Don't use Vaseline or any other petroleum based lube, as those will cause rubber gaskets to degrade over time.

 

[HikeAbout]

Hi @jeffchap, the technician replaced the filter basket o-ring as one of his first troubleshooting steps and the leak was not coming from there. We also comfirmed this by putting shaving cream along that seal (as well as others) during pump operation and saw no sign of leakage.