Feedback on fix for bad plumbing...

Hi. The pool "professional" who plumbed our SWG put it before the heater. We bought the house this past summer. It took me some months of study here and elsewhere to learn this "a bad thing"... that chlorine from the generator will eat the heater for breakfast. Previous owners said they had replaced it a year before. This was a selling point for the house. Hah. I'd like not to replace it again next year.

When I figured this out, it was almost time to turn off the SWG for the winter anyway. So I switched to pucks in a floater. Need to get this fixed before spring opening. (We're in NC, so are open through the winter, using the spa.)

Anyway I'd like to re-plumb it myself. I'm pretty handy and have done some general plumbing, but never a pool. So I'm asking for thoughts and pitfalls to avoid.

Here is the equipment pad now. It's surrounded by tall hedges with 2-story brick wall at the rear, so getting decent pictures isn't easy:
Pool Equipment From Above.jpg
All the equipment except the jet pump on the right is in my sig block. Note the elegant "rats nest" wiring. Still need to clean that up...

As you can see, there's not a lot of space. Nearly all the pipe is low: below 14 inches from the pad. The lines needing change are against the wall in the back. The only solution I can see is to use more vertical space back there.

Here is a sketch of the proposed new layout from the "front," looking directly at the brick wall.
Sketch, Pool Re-pumbing.jpg

This is pretty close to scale. The SWG (Jandy Aquapure) has the sensors inside. Note you can see the gas line for the heater is _above_ everything else in the photo. But here it's _below_ the topmost PVC. Overall this plumbing stands about a foot higher than the existing back there.

Hope this is clear enough. Happy to answer questions. If you see anything else egregiously wrong with the existing plumbing, please say that, too.

I really appreciate all the help received here to date. I'm about 4 months into pool ownership, and it feels like drink from a fire hose. Your generosity with expertise is a great gift. Best to all for the holidays...
 
Last edited:

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
8,378
Central California
Pool Size
12300
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Two tips:

1) I would relocate the temp sensor to the other side of the bypass loop, so you can still get useful readings from it when the heater is bypassed. That's how it is now, but not in your drawing. I'm not sure what that sensor is doing, as it is reading water temp after the heater? So I can't say if it should remain in that function, or if it should be reading pool water temp before it's heated. That might be something to look into.

2) When you purchase your sweep 90s, be sure they are schedule 40 and pressure rated. Big box stores carry sweep 90s that look similar to what you want, but are not (they're actually for low-pressure use, like in drainage systems, known as DWV fittings).
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
22,134
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Water temp sensor should be on the input side of the heater BEFORE the bypass diverter so it always gets the water temp.

This wiki has tips on doing PVC repair and links to online sites to get all the correct schedule 40 fittings that the big box stores don’t always carry...

 
Two tips:

1) I would relocate the temp sensor to the other side of the bypass loop, so you can still get useful readings from it when the heater is bypassed. That's how it is now, but not in your drawing. I'm not sure what that sensor is doing, as it is reading water temp after the heater? So I can't say if it should remain in that function, or if it should be reading pool water temp before it's heated. That might be something to look into.

2) When you purchase your sweep 90s, be sure they are schedule 40 and pressure rated. Big box stores carry sweep 90s that look similar to what you want, but are not (they're actually for low-pressure use, like in drainage systems, known as DWV fittings).
Thanks! Actually I had a note to myself to figure out that sensor by tracing the wiring. I'm not sure it's temp or even that it's in use. There was an Italian acid dispensing system - totally non-functional, mostly cut out - which I removed entirely. Could possibly a remnant of that...
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
8,378
Central California
Pool Size
12300
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
My acid injection system doesn't need to know water temp. But my solar system does. It needs to know the temp of the water in the pool, not the temp of the water coming out of the heater, so my sensor is located right after the pump, before either of my heaters.

I also use that sensor reading when the heaters are off, just for how warm or cold the pool is, for swimming. I have read about some pool owners wanting to know the temp of the water after heating, for whatever reason, so maybe that? Who knows when you inherit a pool...
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
34,681
Laughlin, NV
that chlorine from the generator will eat the heater for breakfast
Just a note, that statement is not true. When the SWCG is operating, the chlorine level of the water coming from the SWCG is not elevated by very much at all.
Low pH is what harms heater components. The pH within the SWCG is elevated at the surface of the plates.
Build up of hydrogen gas generated in the SWCG can be detrimental to any components if located after the SWCG.