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Thread: SWG before Pool Heater

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    SWG before Pool Heater

    Hello. I bought a house that has an 8,000 gallon saltwater pool. It has the Sta-Rite Max-E Therm 400 pool heater and the Jandy PLC 1400 salt cell. I noticed that the salt cell is installed BEFORE the heater. The water goes from the pump to the filter to the salt cell to the heater and then to the pool. Looking at the heater manual, the salt cell is supposed to be installed after the heater. There is about 5-6 feet of pipe between the outlet of the salt cell and the inlet of the heater. I understand that high chlorine concentration in the water coming out of the salt cell could corrode the heating elements of the heater, but would the concentration remain high 5-6 feet downstream of the salt cell where the water goes into the heater? Is this a big problem that could corrode the heater elements? (I know the name of the installer, but apparently the installation was about 3 years ago, so they probably would not take responsibility.)

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    Re: SWG before Pool Heater

    They couldn't install it on the other side of the heater? Is there a heater bypass?
    22k gallon IG pebblefina, Jandy 1.5 HP VS, Jandy CV Cartridge filter, Fafco solar panels, Polaris 360 supply side cleaner, waterfall

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    Re: SWG before Pool Heater

    They may have been able to install it on the other side of the heater, but they did not. It probably would have been more work to do so. There is no manual bypass. Just the heater internal bypass, but, as I understand it, that only controls flow and does not keep 100% of the water out of the heat exchanger.

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    Re: SWG before Pool Heater

    So I won't go into it all but your heater life should be longer if the SWCG is after the heater and you have a valve that bypasses the heater when its not on. How much longer is an open question. Your mileage may vary. But its worthwhile to get this done because its not good long term.
    22k gallon IG pebblefina, Jandy 1.5 HP VS, Jandy CV Cartridge filter, Fafco solar panels, Polaris 360 supply side cleaner, waterfall

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    Re: SWG before Pool Heater

    Thanks. So you think chlorine concentrations are high going into the heater under the current configuration? Is it likely to be causing corrosion and releasing copper into the water?

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    Re: SWG before Pool Heater

    I wouldn't go that far. But I would say that the risk of greater chlorine concentrations is greater and the less harsh you can make that environment in the heat exchanger the better. And even a small amount greater may have long term consequences. Remember you are running this thing whenever the pump is running.
    22k gallon IG pebblefina, Jandy 1.5 HP VS, Jandy CV Cartridge filter, Fafco solar panels, Polaris 360 supply side cleaner, waterfall

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    Re: SWG before Pool Heater

    Would a good middle ground be to put in the manual bypass? The reality is that I live in Houston, so I almost never run the heater. Putting in the manual bypass is likely easier than trying to move the SWG.

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    Re: SWG before Pool Heater

    Absolutely, anything to keep the chlorine concentration low in the heater most of the time.
    22k gallon IG pebblefina, Jandy 1.5 HP VS, Jandy CV Cartridge filter, Fafco solar panels, Polaris 360 supply side cleaner, waterfall

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    Re: SWG before Pool Heater

    So I did a little further studying of the plumbing and found that the distance from the filter outlet to the permanent (because it is attached to a line that goes down into the ground for a waterfall) piping that goes to the SWG is about 4 1/8". They are both at the same height and directly across from each other, so it is a 4 1/8" straight shot between the two. Thus, in order to get the plumbing to go to the heater from the filter outlet, (1) there would need to be an elbow that sends the filter outlet over to the heater and (2) when the line comes back from the heater, there would need to be an elbow going into the permanent piping that would go to the SWG and ultimately back to the pool. That's 2 elbows in a 4 1/8" span. Two elbows don't really fit in that span. That is likely why the installers did not plumb it correctly. Any ideas on how to make this work to fit the two connections in that span?

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    Re: SWG before Pool Heater

    Quote Originally Posted by spozz View Post
    So I did a little further studying of the plumbing and found that the distance from the filter outlet to the permanent (because it is attached to a line that goes down into the ground for a waterfall) piping that goes to the SWG is about 4 1/8". They are both at the same height and directly across from each other, so it is a 4 1/8" straight shot between the two. Thus, in order to get the plumbing to go to the heater from the filter outlet, (1) there would need to be an elbow that sends the filter outlet over to the heater and (2) when the line comes back from the heater, there would need to be an elbow going into the permanent piping that would go to the SWG and ultimately back to the pool. That's 2 elbows in a 4 1/8" span. Two elbows don't really fit in that span. That is likely why the installers did not plumb it correctly. Any ideas on how to make this work to fit the two connections in that span?
    You can use flexible tubing!

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    Re: SWG before Pool Heater

    A picture or two of your equipment pad and piping may help us better visualize your situation.
    Gene
    ​12,300 gal IG play pool - Pebbletec - built 10/1999 || Hayward S360SX 36" sand filter || Hayward Ecostar SP3400 VSP || A&A In-Floor cleaning system || Quik Water Leveler || Quik Dek-clor (limited use)
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    Re: SWG before Pool Heater

    Quote Originally Posted by proavia View Post
    A picture or two of your equipment pad and piping may help us better visualize your situation.
    See below

    IMG_5234.jpg

    You can see the short connection space between the filter outlet and the Jandy 3-way valve that goes to the waterfall on one side and the SWG/pool return on the other side. The white PVC down below are the lines that go to/from the heater. I would need to cut out the short connection between the filter outlet and the Jandy 3-way valve and replace it with (1) an elbow that sends the filter outlet down to the heater and (2) then reattach the outflow pipe from the heater to the Jandy valve inflow with another elbow. The problem is getting the two elbows to fit in the 4 1/8" of space.

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    Re: SWG before Pool Heater

    I would try to re-plumb the heater outlet as shown with the red lines, and put the SWG cell in either location marked in blue.

    swg plumb.jpg
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    Re: SWG before Pool Heater

    Thanks. But that would put the salt cell off the pad and on the ground. Wouldn't that be a problem?

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    Re: SWG before Pool Heater

    You could use some 45's to take it up a bit and bring it down
    22k gallon IG pebblefina, Jandy 1.5 HP VS, Jandy CV Cartridge filter, Fafco solar panels, Polaris 360 supply side cleaner, waterfall

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    Re: SWG before Pool Heater

    May have to do that if no other choice, but that location would be a bit obtrusive because it would block the passage to the back of the heater and back of the house. Any ideas on squeezing the plumbing into the small space to be able to leave the SWG where it is?

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    Re: SWG before Pool Heater

    I just wanted to point out that the cell puts out about 1.25 lbs/24hrs which is about 2 ppm rise from cell input to cell output when the flow rate is 50 GPM. So not much different than dosing a pool manually for a 2 ppm rise. I'm not saying that it will or will not make a difference but just keep it in perspective.
    Mark
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    Re: SWG before Pool Heater

    What does this translate to at a higher GPM (say, 100)? I have a Jandy Stealth JHPU 2.0 pump and clean filter pressure of about 21, so I think that means a GPM closer to 100.

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    Re: SWG before Pool Heater

    100 GPM would be a 1 ppm rise. The higher the flow rate, the lower the ppm rise (more water - same CL).
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
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    Re: SWG before Pool Heater

    Hmmm...and I am guessing that 5-6 ft down the line from the cell output (which is where the water enters the heater), probably even a lesser rise?

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