water flowing backwards after shut off

[anomale]

Hi, not sure if this is the correct place to post but here is the problem....

We have a pool / Spa combo and I suck the water from the spa and return it to the pool to skim the water more efficiently. everything has been great for the past 15 years but recently when I turn off the pump and come back an hour or so later I find that the DE has drained from the filter back into the SPA. I havent tried using the pool skimmers and turning off the pump to see if its flowing back there because its a lot easier to vacuum it back from the spa :lol: .

any ideas what could be causing this?

from what I can tell there are no leaks anywhere in the system (i dont see wet areas)

 

[JasonLion]

That usually happens because an air leak on the suction side of the plumbing is allowing air to accumulate in the filter. When you turn the pump off the air pressure forces the water backwards through the system. It is less likely, but also possible that a pressure side leak is allowing the system to drain down when it is off.

 

[chiefwej]

In had DE coming back through the floor drain into my pool on shut down. It was caused by a failed check valve.

 

[anomale]

thanks where would the check valve be located?

 

[duraleigh]

You may not have one. Post a pic of your equipment.....it can be located virtually anywhere along the above ground piping.

 

[chiefwej]

My check valve was located between the pump and the filter. I cut it out and put in a new one......problem solved.