North Texas freeze / potential upgrades

shmeeps

Member
Feb 23, 2021
6
Dallas, Texas
Pool Size
22000
Surface
Plaster
Like many others, we're having a few issues after the freeze in Texas. I decided before hand to do a quick semi-winterization of my pool equipment instead of leaving it running, as I didn't want to put extra strain on the grid or have any freezes during a possible blackout. Freeze mostly ended on Friday, I waited until Sunday to restart everything. I ran some cool water through the system via a bucket to handle any last ice and let that sit, ensured all my valves were free, then started it up. My pressure gauge died but no big issue to replace there. My booster pump (Pentair LA01-N) also developed a small leak around the inlet/outlet, I'm assuming due to the thread sealant cracking some. The motor developed a bit of a noise, but nothing crazy.

However, after running the main pump (Pentair Challenger CHII N1 1-1/2A / 346206) for 24 hours, it has developed a decent leak around the volute seal. I pulled it apart, ensured the gasket was undamaged (seems to be, but it doesn't seem to sit right in one quadrant of the housing) and put it pack together, getting the metal bracket as tight as I could without wrenching down on it, but the leak persists. I've ordered a new square gasket to try, and I'm planning on lubing up the existing one to get the leak manageable enough to at least keep the water moving for now. I figured I'd get a 3/4" PVC plug and just cut out the booster for now until I've got that fixed up as well. I've also noticed a crack in my inlet valve (Jandy 3-Way Valve) that isn't leaking, but is concerning, and I have had a few existing pinhole leaks that I've been too lazy to address and some other piping pieces / unnecessary elbows left over that I'd like to remove, so I figured I'd just re-plumb everything around the equipment and start fresh. Given that I'm already doing all of this, that the pump is nearing 10 years old and is a single-stage pump, and the booster is 6+ years old, I'm considering replacing the main pump with a two-speed or variable-speed pump, and potentially getting rid of the booster in favor of a robotic cleaner.

My current setup is as follows (~21k gallon pool, ~16'x32', 3' shallow end, 8' deep end):
  • 2 x 1.5" PVC pipes from the skimmers join into a 2" PVC pipe, enter the 3-way inlet
  • 1.5" PVC pipe from bottom drain enters the other side of the 3-way inlet
  • 2" PVC out of the 3-way inlet into Pentair Challenger 346206 1.5 HP
  • 2" PVC out of the main pump, immediately bushed down to 1.5" PVC
  • 1.5" PVC into Hayward SP0714T valve head / Hawyard S244T sand filter
  • 1.5" PVC out of valve head to salt chlorinator, to pool return
  • 3/4" PVC tee pre-chlorinator to Pentair LA01-N booster, to pressure cleaner
My "optimal" plan in my head would be
  • Replace 3-way valve, pipe 1.5" PVC out into 1.5" PVC main pump
  • Replace pump pipe out (2" PVC -> 1.5" PVC) entirely with 1.5", with less elbows / left over pieces
  • Cap 3/4" PVC tee, remove booster, replace with robotic cleaner
My main question here is, since I have a 2" inlet in the system, is there an issue with getting a main pump that has 1.5" inlet/outlet to match the rest of the system, or does it need a 2" inlet/outlet to ensure it can pull an adequate amount of water without burning itself out / ensuring enough water is pulled from both skimmers / bottom drain? And I'm assuming that because my piping is mostly 1.5", I'll be limited to 40-45 GPM? At that point, is a two-speed/variable-speed even worth the increased cost, or will it be mostly wasted? I usually run my pump 8 hours a day; I know the benefit of a two-speed / variable-speed is being able to run it for a longer time at lower speeds, but I'm not sure if there's a minimum flow rate that a pump can effectively run, or something like that, or if there's any major benefit at this pipe size to reducing the flow. My electric rates are low so I doubt I'd see much power savings, but more interested in reduced potential pipe maintenance. I've seen the Whipserflo 1/2 HP thrown around a few times as a recommendation instead for this 1.5" pipes.

For plumbing, the 2" pipe in/out of my pump currently is sch 80, then converts to sch 40. Any issues with just using sch 40, especially assuming less heat/strain with a likely smaller pump? And as far as thread sealant, the last time I used some (to replace my filter head) I used Rectorseal T+2 since I needed it in a pinch. Is that decent enough, or is something else recommended?

Outside of that, any recommendation on pump size/power/models, or on robotic cleaners?
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
13,942
Pleasanton, CA
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
Welcome to the forum!

My main question here is, since I have a 2" inlet in the system, is there an issue with getting a main pump that has 1.5" inlet/outlet to match the rest of the system, or does it need a 2" inlet/outlet to ensure it can pull an adequate amount of water without burning itself out / ensuring enough water is pulled from both skimmers / bottom drain?
The difference is literally immeasurable.

And I'm assuming that because my piping is mostly 1.5", I'll be limited to 40-45 GPM?
Nope! Pipe size does not "limit" flow rate. Smaller pipe just adds more head loss which for a given pump will reduce flow rate a bit. But as I said before, it is really immeasurable.

is a two-speed/variable-speed even worth the increased cost, or will it be mostly wasted?
Two speed or VS speed will always save on energy costs. However, the lifetime costs may or may not pay for itself. That depends on the cost of electricity and how you operate the pump. A single speed can be operated cost effectively by just reducing run time.

For plumbing, the 2" pipe in/out of my pump currently is sch 80, then converts to sch 40.
Are you sure about that? That would be very unusual. If you see a grey nipple in the pump housing, that may still be sch 40. All pool plumbing, pumps, filters, etc are sch 40.

For a robot cleaner:
 

JamesW

TFP Expert
Mar 2, 2011
23,345
For plumbing, the 2" pipe in/out of my pump currently is sch 80, then converts to sch 40.
Grey is usually schedule 80 or CPVC.

CPVC is used to help avoid having the PVC shrink due to heat generated with a no flow condition.

Some people use schedule 80 thinking that it will help with an overheating condition, but it really wont.

I would recommend hi-temp unions which resist heat and allow for ease of installation and replacement.

 

shmeeps

Member
Feb 23, 2021
6
Dallas, Texas
Pool Size
22000
Surface
Plaster
Two speed or VS speed will always save on energy costs. However, the lifetime costs may or may not pay for itself. That depends on the cost of electricity and how you operate the pump. A single speed can be operated cost effectively by just reducing run time.

Yeah, I pay ~9c / kwh, so electric pricing wise I figure it's not worth it. I think even a properly sized single-speed would be better than what I have; a 1.5 hp pump seems way overkill for my system.

Are you sure about that? That would be very unusual. If you see a grey nipple in the pump housing, that may still be sch 40. All pool plumbing, pumps, filters, etc are sch 40.

I think so! It's grey going in, though it's not quite the shiny grey I'm used to seeing with sch 80. Not sure if it's just worn some, or if it's something like CPVC? There's a sch 40 2" -> 1.5" reduced glued directly onto it.

For a robot cleaner:

I was looking at a Dolphin Nautilus, but wanted to get some unbiased opinions. That appears to be the same model under a different name. Glad to know it is a good model.

I would recommend hi-temp unions which resist heat and allow for ease of installation and replacement.

Interesting, so these just thread directly into the pump itself? Do you need any a high-temp thread sealer as well?
 
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