need plumbing diagram for spa overflowing into pool

repairman · Nov 2, 2016

Hi,
I need a plumbing diagram of how to set up a spa (that is higher than the pool) that overflows into the pool like a waterfall. Right now my spa and pool are separate systems but I'm re plumbing everything and moving the spa next to the pool. My spa is great now because it has its own pool pump and heater (but still a Hayward C500 spa filter) with air jet blowers and is really powerful. I don't think I will lose spa power by consolidating and just using the one pool pump and filter (Hayward 4800 DE) and plumbing it right but if you know something I don't please let me know. The main thing is the plumbing diagram of a spa that waterfalls into the pool, but also I want to keep powerful jets and heat in the spa.
Thank you,
Jim (repairman)

JoelFitz · Nov 2, 2016

Easy answer, install a check valve on the main spa return line and leave the line partially open to naturally flow to the spa when the pool is circulating and the check valve stops the siphoning when the pool shuts off.

Several options available but most are dependent on what type of control you're using, whether or not actuators are being used etc...

EDIT: Also usually spa only pumps are larger than pool only pumps so make sure you don't use a lesser pump expecting the same results.

repairman · Nov 2, 2016

Thanks JoelFitz,
I didn't plan on using actuators, just turning valves manually when I wanted to use the spa, 4 or 5x/wk. I wonder if it would be worth it? Do you know the added cost? Thanks for the info on the pumps. I am planning on buying a 2 stage pump and running the pool all the time on the low setting.

JoelFitz · Nov 2, 2016

I don't think it's worth it if you don't have an automatic controller. There're some here that have figured out how to wire them up using an external control but to me that's too much trouble. You'll be okay with a check valve and partially opened diverter valve.

If you want to get fancy, also not knowing the size of the spa return pvc, you can tee a line between the spa return and the pool return and install the check valve there which would allow you to keep the spa return line valve shut all the time instead of partially open. Useful in situations where the spa return is 2.5" or bigger which would make the check valve be restrictive or overly expensive. The "common" line would need only be 1.5 to 2" and would accept almost any check valve.

Google "spa return configuration" there're some good pictures/diagrams there for reference