Adding check valve(s) - question on location

Sk8Surfr

Well-known member
May 28, 2016
88
South Florida
A picture of my current plumbing setup is below. For starters - this is a new pool and I WILL be adding a check valve in location #3 near the salt system when I turn the salt feature on.

When the system is shut off - the intake valve position is 100% pool. The return valve position is 90% pool and 10% spa.

Two main questions:
1. When I turn the system off the spa (while its a champange spa it does not drain a lot) it will drop about 2 inches of water to match the level of the pool. I would like to stop that. Would adding a check valve to location 2 solve that? I'm assuming this is where the draining would be happening?

2. When I clean the filter and break the seal the pump empties and I have to add water with a hose to get the prime back. Should I add a check valve in position 1? OR - I could just rotate the manual valve that controls the pool main drain/dual skimmer flow too I guess?

Trying to go the easiest route here. If adding a check valve to position 1 would solve both my questions - I'll just do that?

IMG_7776.jpg
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
18,959
Northern NJ
Why do you think you need a CV before the SWG cell?

A CV in 2 will keep your spa from draining.

A CV in 1 will keep your pump primed.

Why don’t you use the SPILLOVER feature instead of the return valve position being 90% pool and 10% spa. Running your spillover all the time causes aeration which raises your pH.
 

Sk8Surfr

Well-known member
May 28, 2016
88
South Florida
Why do you think you need a CV before the SWG cell?

A CV in 2 will keep your spa from draining.

A CV in 1 will keep your pump primed.

Why don’t you use the SPILLOVER feature instead of the return valve position being 90% pool and 10% spa. Running your spillover all the time causes aeration which raises your pH.
The salt system says install one so no super-chlorinated water runs back into the filter/pump when the system is off.

Not sure I understand you spillover suggestion - if I activate spillover that sends 100% of the water to the spa. I figured when in pool mode it was good to have 'some' water return to the spa? I have a champagne spa so I like the look of it when we're swimming for it to be full/over flowing.


IMG_7592.jpg
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
18,959
Northern NJ
The salt system says install one so no super-chlorinated water runs back into the filter/pump when the system is off.
It is really unnecessary. The SWG stop generating as soon as the pump stops. This is a carryover from trichlor chlorinators where the problem is not the chlorine but the acid in the trichlor that continues to dissolve and crate highly acidic water AFTER the pump is stopped.

Not sure I understand you spillover suggestion - if I activate spillover that sends 100% of the water to the spa. I figured when in pool mode it was good to have 'some' water return to the spa? I have a champagne spa so I like the look of it when we're swimming for it to be full/over flowing.
If you have a stable pH with little need to add acid frequently then your pool/spa setup is not a problem. I am observing that the aeration the spillover creates usually causes the pH to rise more rapidly then necessary. Rather then the spillover running continuously you can program the spillover to run a few times a day for 15 - 30 minutes to refresh the water int he spa area.
 

Sk8Surfr

Well-known member
May 28, 2016
88
South Florida
It is really unnecessary. The SWG stop generating as soon as the pump stops. This is a carryover from trichlor chlorinators where the problem is not the chlorine but the acid in the trichlor that continues to dissolve and crate highly acidic water AFTER the pump is stopped.



If you have a stable pH with little need to add acid frequently then your pool/spa setup is not a problem. I am observing that the aeration the spillover creates usually causes the pH to rise more rapidly then necessary. Rather then the spillover running continuously you can program the spillover to run a few times a day for 15 - 30 minutes to refresh the water int he spa area.
Gotcha - thanks for the insight - I'll skip the check valve before the salt system then!

I guess if I changed the valve orientation to 0% spa - I could probably eliminate a check valve there too! When off the spa return would basically be shut - I'll move the valve and see if that does it.
 

Sk8Surfr

Well-known member
May 28, 2016
88
South Florida
Adding one more question - I AM adding a pool heater - so if the salt system did flow back it would flow back into the heater - still no need for check valve?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
18,959
Northern NJ
Adding one more question - I AM adding a pool heater - so if the salt system did flow back it would flow back into the heater - still no need for check valve?
Nope.

Even though with a heater you should put in a Heater Bypass - Further Reading

If you put in the bypass the recommended way with a 3 way diverter on the water input and a CV on the heater output then you get your CV for other reasons.
 

Sk8Surfr

Well-known member
May 28, 2016
88
South Florida
Nope.

Even though with a heater you should put in a Heater Bypass - Further Reading

If you put in the bypass the recommended way with a 3 way diverter on the water input and a CV on the heater output then you get your CV for other reasons.
Interesting - thanks for sharing this - I guess I could add an actuator there too to automatically change the water flow when I enter heater mode - just need to figure that part out.

What's the point of the check valve in this instance? To always leave water in the heater?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
18,959
Northern NJ
What's the point of the check valve in this instance? To always leave water in the heater?
The CV keeps water out of the heater outlet when in bypass mode. Assume the heater is leaking or was removed.

This design uses one valve and assures that you cannot accidently dead head the system which you can do if you use a valve on each line and forget to turn one of them.
 

Sk8Surfr

Well-known member
May 28, 2016
88
South Florida
I did as you suggested @ajw22 - here is the plumbing and bypass valve. I wanted to use the other inlet and not run up so high - but with 2.5 inch pipe I did not have enough clearance. I kept it all 2.5 inch except the heater inlet is 2 inch - which I guess is not a big deal since the heater will only be running water through it when its in heating mode.

I bought an actuator and I'll program "Heater" as a Feature in the Pentair control center I guess. Unless there is a different way to have an actuator cycle when you turn on heat?

IMG_7819.jpg
 

borjis

LifeTime Supporter
Aug 19, 2014
3,237
Pacific NW
I applaud your very clean application of PVC cement!
Seen many sloppily applied with glue all over the place.

Beautiful spa by the way.