Should spa spillover return line be closed when pump is off?

[Nickel]

My spa drains to pool level when the spillover valve is open when the pump is off. Is this normal? Can someone explain why it would drain from a return line? (The regular pool return line also has a spa return that fills the spa but that doesn't drain the spa when the pump is off.)
Thanks!

 

[mas985]

When in spillover mode, the pool suction line is connected to the spa return line (through the pump) so the spa siphons back into the pool when the pump is off since the water level is higher than the pool. To prevent this, the spa return lines should have a check valve.

 

[Nickel]

When in spillover mode, the pool suction line is connected to the spa return line (through the pump) so the spa siphons back into the pool when the pump is off since the water level is higher than the pool. To prevent this, the spa return lines should have a check valve.

That makes sense. I'll add a check valve into the system. (It doesn't have one now. Only a check valve at the pump.)
EDIT: Although I still don't understand why the pool return line that has a diverter to the spa return doesn't drain the pool. Maybe it's because it's physically lower in the system or there's a check valve I've missed?
Thanks!

 

[mas985]

Where is that check valve. If it is right after the pump or right after the filter, it should still prevent backflow so it may not be operating properly. Can you post some pictures?

 

[Jimrahbe]

Nick,

It would be odd not to have a check valve in the spa return line that feeds the spillover.

Please show us some pics of your equipment pad, as some check valves do not really look like check valves that we see today.

Thanks,

Jim R.

 

[mas985]

That makes sense. I'll add a check valve into the system. (It doesn't have one now. Only a check valve at the pump.)
EDIT: Although I still don't understand why the pool return line that has a diverter to the spa return doesn't drain the pool. Maybe it's because it's physically lower in the system or there's a check valve I've missed?
Thanks!

Because the spa is higher than the pool, it will always drain from spa to pool (high to low) if there is no check valve or if you a have valve, it failed.

 

[Nickel]

Where is that check valve. If it is right after the pump or right after the filter, it should still prevent backflow so it may not be operating properly. Can you post some pictures?

Here are some pics of my system. The first two photos are the return lines coming from the filter. The last pic is the check valve between the pump and the d/e filter. (The heater is busted and not plumbed in any more.) Thanks.

EDIT: I've ordered a new flapper to rebuild the check valve, hoping that would fix the issue. But it still puzzles me why the spillover drains but not the spa return.)

 

[mas985]

There is a check valve after the pump and that should prevent backflow through the pump. However, it also looks like you have a bypass check valve for the spillover as well and it is probably that one that has failed. That connects the pool return with the spa return.

 

[Jimrahbe]

I spy a check valve.. Can you see it???

It is white and fat at the bottom and narrower at the top.



Jim R.

 

[Nickel]

I spy a check valve.. Can you see it???

It is white and fat at the bottom and narrower at the top.

Jim R.

Ooh. I didn't realize that was a check valve. Thanks so much! I guess it needs to be replaced.
Thanks for the help! (I was only familiar with the Jandy style of check valve with the clear window on top.)

 

[Nickel]

I spy a check valve.. Can you see it???

It is white and fat at the bottom and narrower at the top.


View attachment 504284
Jim R.

It seems obvious now. I just wasn't familiar with that type until now. Thanks for the education and help!

 

[Nickel]

There is a check valve after the pump and that should prevent backflow through the pump. However, it also looks like you have a bypass check valve for the spillover as well and it is probably that one that has failed. That connects the pool return with the spa return.

Thanks Mark! I'll replace that. Appreciate the help!