Bubbling noise from multi port valve

Cngilley

Member
Jul 30, 2020
5
East Tennessee
I have a brand new pool. Pool equipment is 2-3ft above the pool. When I turn off pump there’s a slight bubbling noise that appears to be coming from multi port valve at sand filter. If you put your ear to the pipes you can hear water slowly bubbling and sounds like it’s draining back to pool. It takes several hours but all the water drains back to the pool and pump loses its prime. I’ve checked all the usual stuff: pump lid and O ring, used soapy water on all suction joints and unions, pump drain plugs. Pool installer said he couldn’t find anything and to just run pump 24hrs. Any ideas? Bad O rings in brand new multi port valve?
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,827
SW Indiana
Welcome to TFP!

Generally when the equipment is elevated, a check valve is added to the pump inlet line to prevent backflow.
 

Cngilley

Member
Jul 30, 2020
5
East Tennessee
Welcome to TFP!

Generally when the equipment is elevated, a check valve is added to the pump inlet line to prevent backflow.
No check valves were installed.....Noob question, i understand the water past the check valve won't be able to flow back to pool but won't water before the check valve still flow back?
 

Bama Rambler

Mod Squad
TFP Expert
Bronze Supporter
LifeTime Supporter
Jun 22, 2009
24,064
SouthWest Alabama
That bubbling you hear means that there's a leak somewhere in the system. It could be inside the multiport valve. If there are no leaks the system will remain full of water. Even if it has a tendency to flow one way or the other the syphon created by the movement will draw water into the system so it remains full.

Sometimes air leaks can be a bear to find, but if I were you, I'd start looking for one.
 

Cngilley

Member
Jul 30, 2020
5
East Tennessee
That bubbling you hear means that there's a leak somewhere in the system. It could be inside the multiport valve. If there are no leaks the system will remain full of water. Even if it has a tendency to flow one way or the other the syphon created by the movement will draw water into the system so it remains full.

Sometimes air leaks can be a bear to find, but if I were you, I'd start looking for one.
Thanks, i think its an air leak as well and have tried water hose, soapy water, and shaving cream everywhere and can't find anything. Pool installer was zero help. Noise seems to be coming from valve so not sure if I should take it apart and check it or exactly what i should do.
 

Bama Rambler

Mod Squad
TFP Expert
Bronze Supporter
LifeTime Supporter
Jun 22, 2009
24,064
SouthWest Alabama
The valve is where you're hearing the bubbling because it's most likely the high point in the plumbing, but that may not be where the leak is. It's easy enough to take the top off the multiport and look at the gasket and partitions, so if you wanted to do that it wouldn't hurt anything.

Can you see the waste outlet flow, or is it hard plumbed?
If there's no inline sight glass and it's hard plumbed I'd probably take it loose and run the pump to see if there's anything leaking out of it.
 

Cngilley

Member
Jul 30, 2020
5
East Tennessee
The valve is where you're hearing the bubbling because it's most likely the high point in the plumbing, but that may not be where the leak is. It's easy enough to take the top off the multiport and look at the gasket and partitions, so if you wanted to do that it wouldn't hurt anything.

Can you see the waste outlet flow, or is it hard plumbed?
If there's no inline sight glass and it's hard plumbed I'd probably take it loose and run the pump to see if there's anything leaking out of it.

there is a small sight glass on the waste line. on initial install it had a water leak there but they fixed that before completing the pool. i do not see anything going on with it while the pump is in normal operation
 

Bama Rambler

Mod Squad
TFP Expert
Bronze Supporter
LifeTime Supporter
Jun 22, 2009
24,064
SouthWest Alabama
I'm not sure you can see a small leak out the waste port through that tiny sight glass. It's likely just a trickle and would be running along the very bottom of the pipe.
 

sktn77a

Gold Supporter
May 16, 2010
1,755
Chapel Hill, NC
Brand new pool? Tell them to replace the multiport valve (most likely culprit). If that doesn't cure the problem, there's a leak in the plumbing - they need to find it and fix it. Brand new pool - you shouldn't have to do any of this yourself!