Need for 2nd Check Valve between Rainbow 320 and heater?

Paul3894

Member
Mar 12, 2021
6
Plano, TX
I have a Rainbow 320 in-line chlorinator. It already has a check valve incorporated in the bottom of it. Pool guy told me today I should have another check valve installed in the plumbing line between the chlorinator and heater to ensure chemicals do not flow into heater. After thinking about it it struck me as odd since he installed the heater to begin with and did not mention it at the time of install. Is the Rainbow 320's built-in check valve sufficient to protect the heater or is a secondary check valve needed? I have not had any issues with heater in 2 years since install and the prior heater. Thanks for your input.
 

HermanTX

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May 20, 2020
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I see no need for the second check valve. Mine is set up just like yours. Worked for years. I do not use the chlorinator any more for pucks as I converted to LC but prior to that had it for 10+ years with no issue.
Now would he be discussing a heater bypass flow loop? That would require not only a check valve but also a manual valve to either divert flow to the heater or to by pass it directly to the return lines via the chlorinator.
 

Paul3894

Member
Mar 12, 2021
6
Plano, TX
No the pipe he is talking about is between heater and chlorinator with water direction flowing towards chlorinator then out to pool.
 

HermanTX

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May 20, 2020
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No the pipe he is talking about is between heater and chlorinator with water direction flowing towards chlorinator then out to pool.
I understood that but maybe need to clarify. My chlorinator has a check valve incorporated that is a fitting directly before the "tee" body of the chlorinator. That is the check valve I thought you were referring to in your original post. I interpreted your request to add a second check valve before that. If you have the check valve shown in the picture (between the pipe marked POOL and the Chlorinator - it has a arrow on it) then I see no need to add a second check valve. If you do not have this check valve then I would agree it should be added.

Return Plumbing - 2 lines_LI.jpg
 

Paul3894

Member
Mar 12, 2021
6
Plano, TX
i have a check valve (circled in yellow) My understanding is he proposes to put one in the pipe with blue arrow pointing at it.
 

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HermanTX

Gold Supporter
May 20, 2020
1,520
Katy TX
Pool Size
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i have a check valve (circled in yellow) My understanding is he proposes to put one in the pipe with blue arrow pointing at it.
The CV you have circled in yellow is to prevent back flow from your spa (I assume that is where that pipe is going- does it control your spa overflow into pool or does it go to all the spa jets?) You do need a CV on the right side of your chlorinator and it appears the only place that can be done is in the area where you marked in blue. So agree with your pool guy that a CV should be placed before the chlorinator wherever there is room.
 

Paul3894

Member
Mar 12, 2021
6
Plano, TX
Thank you for the advice. I approved the install. Just seemed a little odd they didn’t catch it when they installed the heater to begin with.
 

HermanTX

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May 20, 2020
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Katy TX
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Thank you for the advice. I approved the install. Just seemed a little odd they didn’t catch it when they installed the heater to begin with.
In reality, whoever installed the chlorinator should have installed a check valve at that time.
I no longer use my chlorinator. It only gave me problems, i.e. the oring on the top was a nuisance to always change it because it was exposed to high chlorine levels in the puck tower container. I just use a floater in the pool when I need to use pucks (such as on vacation or away from home for couple of days). This always ensure chlorine is in the pool regardless if pump is running or not.