PVC Plumbing / Multiple Check Valves

Draco1219

Active member
Apr 22, 2016
44
Dallas, PA
Hello everyone,

Thank you in advance for your help and guidance, I really appreciate it! I have a question regarding whether or not I need to install a second check valve in my PVC plumbing.

IMG_20160422_130451.jpg

As you can see in my current setup, I have a check valve that is sitting in front of the discharge pipe from the heater. Last year I had a pool company install the diverter which will bypass the heater. (I had copper in my water and thought it was from the heater, so I had replaced the heater and install the bypass). When they installed it, they did not say I needed a second check valve.

This year I am installing a salt water chlorinator cell right where the current chlorinator is. After looking at the plumbing, if the heater is bypassed, there is no check valve between the chlorinator and the pump/filter. There is, however, a long vertical PVC pipe going up.

I already bought a second check valve, but my concern is that it may add too much back pressure on the system. I currently have a 1HP hayward super pump and it's roughly a 75 foot run to the pool.

My question is. Do I need to even have a second check valve BEFORE the chlorinator right next to the vertical pipe? If so, will this put too much extra "strain" on my pump with the added back pressure?

Thank you again for taking the time, I appreciate it!
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
42,989
Tucson, AZ
:wave: Welcome to TFP!!!

No you do not need another check valve. In fact, with the SWG, you really do not even need the one that you have installed now. You could open up the check valve and remove the flapper if you so desired.
 

Draco1219

Active member
Apr 22, 2016
44
Dallas, PA
:wave: Welcome to TFP!!!

No you do not need another check valve. In fact, with the SWG, you really do not even need the one that you have installed now. You could open up the check valve and remove the flapper if you so desired.
Thank you for your quick response, I appreciate it.

May I ask why it's not needed? Isn't the water super chlorinated just like if it were a trichlor dispenser?

Is the reason why it's not needed is because the backwash water can't travel up?
 

gwegan

TFP Expert
Apr 19, 2013
2,769
Sacramento, CA
Its not needed because if the first bypass valve is closed it not going to allow much if any water to go backwards into the heater.

And while I'm no expert the SWG produces chlorine and sodium. Nothing else really. The triclor tabs add chlorine, CYA and raise the Ph of the water, so they are much more harsh than just the SWG.
 

Draco1219

Active member
Apr 22, 2016
44
Dallas, PA
I'm not worry about the heater being affected since there is a check valve protecting it.. I'm worried about the water traveling up, pass the bypass, and back into the filter/pump. I guess the filter won't really be affected, and it's not likely the water will hit the pump.-
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
42,989
Tucson, AZ
The problem is that the trichlor tablets result in very acidic water when the pump is not on and there is no flow, it is that water that can backup and damage the heater.

The SWG just makes chlorine and raises the pH a bit, so that would not damage the heater, not to mention it will only be generating when the pump is actually running, so nothing could go back to the heater anyway.
 

Draco1219

Active member
Apr 22, 2016
44
Dallas, PA
The problem is that the trichlor tablets result in very acidic water when the pump is not on and there is no flow, it is that water that can backup and damage the heater.

The SWG just makes chlorine and raises the pH a bit, so that would not damage the heater, not to mention it will only be generating when the pump is actually running, so nothing could go back to the heater anyway.
Thank you very much for your input I appreciate it. Have a great weekend!