Cold water leaking from spa return when in spa mode

[AggiEngineer]

This is my first post but I’ve been lurking for a couple of months. TFP is such an amazing resource!

I ran my spa for the first time and while everything seemed to be operating as it should, I noticed a small amount of cold water (56 degrees) coming up through the spa return in the floor. That doesn’t seem normal but is it? I’m guessing my automatic 3 way valves aren’t entirely closing? If that’s the case, how does one fix that? Thank you.

 

[AggiEngineer]

Well crud. Just found post that sounds like same issue. Sorry y’all

Cold water in spa

Hello, we have had our pool for a couple of months, so learning a lot. When we heat our spa (it's the same level of the pool), it heats nicely, but we feel cold water coming from a single floor jet. This jet is connected to the other pool jets, so when in pool mode they are all flowing and when...

www.troublefreepool.com

 

[ajw22]

Welcome to TFP.

Post pics of your equipment pad, valves, and spa if you need more help.

 

[AggiEngineer]

Thank you ajw22. I will take some pics in the daytime. Reading that other post above, I definitely have similar symptoms. I am able to eliminate the cold water entering the spa floor return by completely turning off the spa return valve (aka fountain) OR turning off the pool return and tanning ledge return valves. I believe this proves that I'm experiencing that siphon effect described in the other thread. I don't really understand how this is possible though. If the pool level and spa level were at equal heights, there should be no way to create a siphon effect from the higher level pool returns to the lower spa return because the two bodies of water are at the same height. That being said, I did not pay close attention to the height differences between 2 bodies of water while this was happening. It is possible my pool height was ever so slightly higher.....more investigation is needed!