Back pressure in pool. Where does suction side begin?

Bellrock99

New member
May 23, 2021
3
Newport News Virginia
40,000 gal ingroundpool, 1.5 hp hayward superpump. The equipment is about 24” above the pool. When I Darn off the pump ther is a massive backflow of water- blows off the skimmer lids- water seems out of teh strainer lid, etc. I understands this is due to air getting into the system somewhere on the suction side. I can hear the water in the sand filter gurgling, so I know there is air in in once things pressurize. On startup, I bleed all of the air out of the tank but it quickly refills. There are definitley air bubbles in the strainer. - I will troubleshoot that today.

Under the thought that there may be more than one source of air intrusion, posts it has been suggested that air could be leaking in through the spider gasket in the multiport valve. I thought, by definition, once the water flowed past the impeller, it was now the pressure side.? Regardless of terminology, if the air is ending up in the filter, is the spider gasket a likely culprit ( after I get all of the air bubbles out of the strainer). In the attahced, I assume the red piping is suction side and the blue and green are pressure side, but anything in the blue area between pump and filter could contribute to air in the filter?

Lastly to troubleshoot the truly suction side, I have seen it suggested to run a hose over the strainer pluig, basket, inlet pipes, etc. to see where the bubbles stop. However, my pool equipment is inside the body of the house and water pooling on the floor can seep into the adjacent carpeted bedroom. Other than soap suds around the joints whcih I have had very little sucess with... Is ther a way to get water on these areas without flooding the floor?

Thanks!
 

Attachments

  • B20EA381-672D-4A5F-BBA8-896E83E04DB8.jpeg
    B20EA381-672D-4A5F-BBA8-896E83E04DB8.jpeg
    75.7 KB · Views: 12
  • E85833EB-2ABB-4B8F-B0EF-957126D9CC7B.jpeg
    E85833EB-2ABB-4B8F-B0EF-957126D9CC7B.jpeg
    324.4 KB · Views: 7
  • 66280E2D-8E2E-4C25-BB35-BCDC3C27D002.jpeg
    66280E2D-8E2E-4C25-BB35-BCDC3C27D002.jpeg
    283.1 KB · Views: 7
  • E5516C72-CF2D-4FDF-8C97-C8D06D1B23EC.jpeg
    E5516C72-CF2D-4FDF-8C97-C8D06D1B23EC.jpeg
    256 KB · Views: 7

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
43,662
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Welcome to the forum!
First step is to clean and lubricate with pool lube (Pool Lube - Further Reading) the gasket on the pump basket lid. Also check the drain plug orings on the pump. After that, be sure the water level is high enough in the pool and the that the skimmer weir door is not stuck or sticking closed.
I would not worry about the pressure side (after the pump) as that can only let air in when the pump is off. And that is a very rare occurrence.
I suggest you read ABC's of Pool Water Chemistry.
 
  • Like
Reactions: Bellrock99

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
14,001
Houston, Texas
Hi, welcome to TFP! Everything past the impeller is on the pressure side. When the pump is running air would be forced out on the pressure side, along with any water that could be forced through the opening. It may suck air into the system briefly when the pump is turned off and the water in the system is seeking level. If this was the case you would see water loss from the multiport while the pump is running. Most air introduced into the system comes from the suction side. Follow Marty's recommendations and see if they help. We do have other troubleshooting ideas to try if this doesn't fix the problem.
 
  • Like
Reactions: Bellrock99

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
33,033
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
I understands this is due to air getting into the system somewhere on the suction side.
Welcome to TFP! :wave: Actually, air can get pulled "IN" from anywhere depending on if the pump is on or off, so you'll want to carefully inspect everything at the equipment pad. The suction side (pump intake back to the pool) can suck air "in" which is typically evident in air in the pump strainer pot, low prime, or air bubbles at the return jets. A leak on the pressure side after the pump outlet can result in water seeping out. But not all air leaks can show no evidence of water. Sometimes you might hear a hissing sound or see a quick spurt of water when you flight the pump off, so watch and listen for those. Check the basic areas like clear lid O-ring for silicone lube, fittings for leaks, filter pressure gauge, etc. But it does sound as if air is getting pulled in from somewhere. Since you can't just pour water over everything in that shed, try things like smoke, saran wrap, etc to see if you notice a difference.
 
  • Like
Reactions: Bellrock99

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
33,033
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
whats a good smoke source?
Last time I tried that I think I picked up some incense sticks locally. Smoke is just a little tricky if there is any wind. Some have tried shaving cream as well, but I find that a bit messy and hard to see a suction leak unless it's significant.
 
Thread Status
Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.