Infinity edge pool return to basin question

[Goahead]

Hi everyone,

Almost ready to water proof tank, after gathering material for almost 10 years

Now, i am starting to think more deeply in how everything is going to work, and back siphon to basin came to light.

I dont want to rely on a check valve only...better trust physics.
I could had a hartford and vacuum valve in the return to pool, but i cant! I still have the lower return to basin to block. Yep, since in the suction side of the pump, i will have the catch basin and the bottom drain of pool.

Please look at picture (sorry for my paint skills), will the hartford work and avoid water to back siphon to catch basin?




Isnt the pump going to lose prime everytime it stops running?..or just loses prime when check valve fails and vacuum valve engages?

Please advise

Kind regards
G.

 

[bdavis466]

Your idea seems needlessly complicated. The check valves are very reliable if oriented correctly.

If you want more protection than that then what about an automated valve that is only opened when the pump is operating?

 

[Goahead]

Hi Brian,

Thank you for your reply.

Yes i understand that check valves are reliable, but they will fail to...and if i have debris being sucked, it will fail sooner.
So i need a plan B in case it fails.

Electro valve as you suggested, seems to be a good option, that's something that crossed my mind to, i just dont see anyone mention the use of it, in infinity edge pools or spas..at least in all documents that i read over internet. Dont know if they fail faster then mechanical/physics tech or they are just used in irrigation circuits.
Most electro valves are 12VAC or 24VAC
From this example:
https://www.holmanindustries.com.au/products/50mm-solenoid-valve-pro-series-150-vk7102/#squelch-taas-tab-content-0-1 in specs, i dont know if PSI loss is important.

What do you think?

kind regards
G.

 

[JamesW]

I would suggest that you use 2 Jandy check valves. As long as they are after the pump basket, the debris should be minimal. You could even use 3 check valves if you feel that that would be helpful.

If you can create a screen for the intakes without blocking the flow of water, that would help.

 

[Goahead]

Hi James,

I would suggest that you use 2 Jandy check valves. As long as they are after the pump basket, the debris should be minimal. You could even use 3 check valves if you feel that that would be helpful.

If you can create a screen for the intakes without blocking the flow of water, that would help.

The pipe from catch basin will probably never suck debris, since it is above the basin floor. Water from basin will be "free" of trash because the path from weir wall and basin will filter the biggest debris (a path of rocks)...but the other inlet coming from bottom of pool, will never pass any type of filter..so it will suck anything that lays in bottom of pool. My fear is when pump shuts down, it will back flow for a second (direction bottom of pool to catch basin), and that may send garbage back to check valve.

Brian,

Electro valves also relies in diaphragm and internal pressure difference to be able to open and close. The way i see it, the bottom inlet (bottom of pool) as more water pressure then the outlet water (return to pool)...so it may not work as expected.
See this irrigation valve, that is similar to any solenoid valve:
https://www.youtube.com/watch?v=5rokXHhxRSw

So if i have more pressure in inlet then outlet...it will never close

More suggestions for redundancy protection in back siphon?

regards
G.

 

[JamesW]

The check valves should shut immediately as soon as the water flow stops. You're not going to get any backflow.

I would do 2 Jandy check valves at the outlet of the pump and you will be fine.

What pump are you planning to use?

What is the target flow rate?

 

[bdavis466]

I wasn't talking about a sprinkler type valve rather a Jandy two port valve with a 24v actuator on it - the same as what your automation control will use.



James suggestion using multiple check valves is pretty much bullet proof and no electronics involved. Most check valve failures that I've seen are a result of improper installation and orientation.

 

[Goahead]

The check valves should shut immediately as soon as the water flow stops. You're not going to get any backflow.

I would do 2 Jandy check valves at the outlet of the pump and you will be fine.

What pump are you planning to use?

What is the target flow rate?

Hi James,

Cannot put check valve in outlet of pump, since i still have the pool drain, that will be connected to inlet of pump (red connection in my uploaded picture.)..that will back siphon.
So check valves redunduncy must be inserted in pink pipe (picture above)


I currently have a used pump 11m3/h (+/-50GPM). Pool tank is just 6600gallons but weir wall is 9meters long.
If weir wall is straight leveled, less then 1,5mm, the pump may work fine..if not..i will buy a better one.

Brain,

Thank you for picture...i didnt know they sell valve atuators seperatly from valves.

Yep 2 valves may be ok...just a bit concern about loosing suction flow do to the springs in check valves. It will increase pressure, making me loosing GPM to.

Anyway..i think i will do it like picture below:

Would that work?

Kind regards
G.

 

[JamesW]

You can put a check valve on the suction going to the basin. A Jandy valve is the best choice. They have several sizes. Most likely, you will need a 2" X 2.5" or a 2.5" X 3".

Note: You can't put a vacuum breaker on the suction side because it's suction.

 

[bdavis466]

The cool guys take the Springs out of the check valves so you don't lose anything and the natural backflow of water makes the valves slam shut. the Springs are really only needed if the valve is oriented in a position where gravity doesn't make it close naturally...

 

[Goahead]

Just a quick picture of pluming...all done by me...
Hope theres no leaks.
You can notice the check valve above the normal valve. That is to avoid pool water retunr to the compensation tank on the left of picture.


Kind regards
G.