water draining from spa to pool

[repairman]

When I use my pentair valve activators (Easytouch), with the pump off, as the valves turn I lose water into the pool. My spa and filter are both above pool level. I oversized the plumbing with 3" piping from spa to valve and 2 1/2" for the rest so there is lots of water flow if a valve is open. The activators turn slow enough that I lose enough water to have to pump it back in every week or sooner. What's the solution. If I make a loop and bring my line from my spa higher than the top of the filter (it's higher than the spa) will that do it? or does it just need to be higher than the spa?
I have check valves coming out of my filter and heater so if water is drying from the filter I think it would only drain back into the pump.
Does the intelliflo pump allow water to flow backwards through it when off? If it doesn't, then I don't have to worry about the filter draining. If it does then a check valve from the pump to the filter would stop that, but it wouldn't be necessary with a loop taller than the filter, right?
Jim

 

[1poolman1]

Doesn't matter how high (within reason) you run the plumbing, if the system is air-tight water can siphon backward. A check valve between the pump and filter should work.

 

[repairman]

What if the water is draining directly from the spa to the pool (not the filter) through the 3 way input valve to the pump? This is only when the valves are turning, which they do slowly if automated.

 

[1poolman1]

What if the water is draining directly from the spa to the pool (not the filter) through the 3 way input valve to the pump? This is only when the valves are turning, which they do slowly if automated.

If you open a port in the suction valve to both the pool and spa as it rotates, yes, you can get water to flow to the pool from the spa. A .5# spring check valve in the pool suction line should prevent that. I understood your first post to say it was flowing from the return line back through the system to the spa.

Under what may be considered "normal" conditions (there's really no such thing as each pool is a custom pool), any water lost to a valve rotation would be replaced the next time the system activates. Its never good practice to isolate the spa from the pool completely during normal filtration unless it has its own filter system.

With the system in "pool" (default) position, all the water should be pulled from the pool, run through the filter, heater, etc. and just enough diverted to the spa to keep it "fresh." That means your spa should overflow each day as the filter runs. That would make up for any loss of water back to the pool from a valve rotating.

 

[repairman]

Thanks. Yes, you're right, every pool is a custom pool, and lot's of credit to you to know enough to understand and fix all these different systems!
Sorry if I didn't make clear that water is only flowing out of the spa when the valves turn, not into it. I think it is running directly from the spa to the pool through the suction valve as it slowing turns between the spa and pool settings. (Spa is higher than pool) And for this you say that installing a .5# check valve on the pool side suction should give enough resistance to stop that? Makes sense. How much # is a normal check valve for 2 1/2" piping and is .5# less than that?
I understand the set-up you describe with overflow running in pool mode would eliminate the problem, but I haven't modified my spa shell to overflow into the pool yet. So until I do, the check valve should eliminate the spa drainage. Please confirm this one more time before I do it.
One more question. When I installed my plumbing, the Pentair rep on the phone told me I needed to install a check valve between the heater and chlorinator, which I did, but I also have a check valve between my three-way return valve and the spa which seems redundant. Can I get rid of the check valve out of the heater? The pool is not a concern because it is below the pad, and, there's a check valve between the filter and heater so water cannot flow backward from the heater.
Thank you,
Jim
Here's a picture. Never mind the bypass loops I put on pool suction and spa return. That was to run the spa and overflow at the same time, which I haven't tried yet.. You can see the check valve coming out of the heater on the right, then the chlorinator, and going left and down out of the 3-way you can barely make out a black check valve going underground to the spa.