Spa drains to pool while in spa mode or when off in pool mode

[Psguy2021]

A bit of background, this is an old pool with an above ground spa that waterfalls. I’ve changed almost all the equipment except for the heater (so, new filter, pentair valves, pentair panel, auto fill, check valve). No matter what I do, I lose a few inches an hour from the spa to the pool in spa mode or while off (and the valves turned to pool mode). The spa stops losing water when it reaches above the valves.

One thing I’ve noticed the last two days is that the spa doesn’t always lose the same amount to the pool.

My pool guy is out of ideas so I’m hoping you all might have something he hasn’t tried. It’s driving me crazy, any ideas?

 

[Jimrahbe]

P,

Normally, when spillover spas drains back into the pool, it is because the check valve on the return line is bad..

Your pics don't show a check valve, but it should be in the line that goes to the Spa jets (returns).

It could be there, but the angle of the pics might be hiding it.

Thanks,

Jim R.

 

[Psguy2021]

Thanks, showing another angle as there’s supposed to be a new check valve.

 

[Jimrahbe]

P,

Unless the heater only runs the spa, that check valve is not the one I am talking about...

You have a Return valve where your automation either selects Pool or Spa.. The Spa pipe, which normally goes to the spa jets (returns) should have a check valve..

I can't see under the valves in that pic..

Thanks,

Jim R.

 

[Psguy2021]

You were right, I didn’t have a check valve in the spa. Added one yesterday and the spa is working like it should. Thanks!