Going from 1.5 to 2 inch pipe

[Belo]

So I have a 24,000 gallon inground. My research tells me that 1.5" piping is really only efficient to ~18k gallons and I really should have a 2" system for more flow, less velocity. Clearly I'm not going to dig up all my 1.5" piping underground but as I'm in the process of replacing a dinosaur of a 1hp static pump I'm realizing if there was a time to do anything it's now.

My multiport is 1.5" and max 75gpm
My brominator is 1.5"
Sand filter rated at 45gpm at 1.5" and 80gpm at 2"
My heater is piped for 1.5" max 125gpm

My current understanding is that I don't really need or could I even use without risk a 3hp pump. The whisperflo series only comes in 2" but provides a nicer hp efficiency curve. I do not wish to replace all my equipment, so I guess my basic question is does it make any sense to have a 2" pump and stepdowns in the system everywhere else?

 

[Bperry]

So I have a 24,000 gallon inground. My research tells me that 1.5" piping is really only efficient to ~18k gallons and I really should have a 2" system for more flow, less velocity. Clearly I'm not going to dig up all my 1.5" piping underground but as I'm in the process of replacing a dinosaur of a 1hp static pump I'm realizing if there was a time to do anything it's now.

My multiport is 1.5" and max 75gpm
My brominator is 1.5"
Sand filter rated at 45gpm at 1.5" and 80gpm at 2"
My heater is piped for 1.5" max 125gpm

My current understanding is that I don't really need or could I even use without risk a 3hp pump. The whisperflo series only comes in 2" but provides a nicer hp efficiency curve. I do not wish to replace all my equipment, so I guess my basic question is does it make any sense to have a 2" pump and stepdowns in the system everywhere else?

That’s what I have on my 27k gallon pool. I only use a 1.5hp pump and run it 24x7 at low speed so I’m no where close to the pipe flow capacity. You’ll be fine but not sure why you’de need a 3hp pump unless you have a bunch of water features.

 

[ajw22]

So I have a 24,000 gallon inground. My research tells me that 1.5" piping is really only efficient to ~18k gallons and I really should have a 2" system for more flow, less velocity.

Your research finds old thinking. There is no relationship between the HP required and the gallons in a pool.

My multiport is 1.5" and max 75gpm
My brominator is 1.5"
Sand filter rated at 45gpm at 1.5" and 80gpm at 2"
My heater is piped for 1.5" max 125gpm

Yes, your equipment has maximum flow rates. I am not sure why your sand filter has such a different flow rate for 1.5" then 2".

Your signature does not have a heater model listed.

I doubt you can push 70-80 gpm through your system even with a 3 HP pump. Pump curves do not show you the dynamic head of your system.

My current understanding is that I don't really need or could I even use without risk a 3hp pump. The whisperflo series only comes in 2" but provides a nicer hp efficiency curve. I do not wish to replace all my equipment, so I guess my basic question is does it make any sense to have a 2" pump and stepdowns in the system everywhere else?

Getting a 3HP pump will not put anything at risk. You should never be running a VS pump at maximum RPM and HP.

A 3 HP pump will be the quietest and most energy efficient pump running at whatever RPM and HP works best for your equipment.

 

[Belo]

Your research finds old thinking. There is no relationship between the HP required and the gallons in a pool.




Yes, your equipment has maximum flow rates. I am not sure why your sand filter has such a different flow rate for 1.5" then 2".

Your signature does not have a heater model listed.

I doubt you can push 70-80 gpm through your system even with a 3 HP pump. Pump curves do not show you the dynamic head of your system.



Getting a 3HP pump will not put anything at risk. You should never be running a VS pump at maximum RPM and HP.

A 3 HP pump will be the quietest and most energy efficient pump running at whatever RPM and HP works best for your equipment.

Regarding HP and gallons, I was referring to flow and that a 2" pipe can move more volume with less velocity. So there is data regarding the right size pipe for volume of pool. It just so happens that obviously the higher hp pumps are paired with the 2" pipes. Sorry for the confusion.

I don't know why either, but that's what's in the hayward manual and I wouldn't second guess them haha.

It should, it's an HT250. Old, but still works well.

 

[Belo]

That’s what I have on my 27k gallon pool. I only use a 1.5hp pump and run it 24x7 at low speed so I’m no where close to the pipe flow capacity. You’ll be fine but not sure why you’de need a 3hp pump unless you have a bunch of water features.

For the efficiency. A 3hp pump running at 1.5hp will be far more energy efficient than a 1.5hp running balls to the wall. You're correct that I do not need a 3hp pump and would likely never push it past 2hp.

 

[Belo]

Small but important update. I'm seeing that all the larger pumps requrie a 208/230 line and I don't have that running to my pool and if this project would require a new line, new pool piping and a more expensive pump then I'm probably never going to have any ROI for energy savings.

Side note, the newest pentair inteliflo3's are nowhere to be found so that kinda sucks.

IntelliFlo3® VSF Pool Pump

The Intelliflo3 VSF pool pump includes auto regulating flow technology, energy savings, and superior performance for crystal clear water.

www.pentair.com

 

[ajw22]

I don't know why either, but that's what's in the hayward manual and I wouldn't second guess them haha.

I would. Low RPM and slow flow is the way to run modern VS pump. Pipe size make les of a difference unless you have a spa that needs higher flows for spa jets.

Intelliflo3 is available at...

Pentair IntelliFlo3 VSF 3.0HP

All Intelliflo pumps require 240V. If you don't have that you can look at the Intelliflo i1 or i2 that run on 120V.

IntelliFlo® i1 and i2 Variable Speed and Pool Pump

The IntelliFlo i1 & i2 pumps move water more efficiently at lower speeds. They provide increased energy savings versus conventional pumps. Shop here!

www.pentair.com

 

[Newdude]

So there is data regarding the right size pipe for volume of pool

That data exists because of the industry myth that you must turnover your water X amount of times per day. The amount of crud falling in the pool determines how much filtering you need, and will vary greatly throughout the season with more needed in the spring and fall and much less needed mid season.

Your own needs may vary from your neighbors if his tree crud blows your direction or vice versa.

I'm seeing that all the larger pumps requrie a 208/230 line and I don't have that running to my pool

The intelliflo i2 was designed for this exact scenerio.

 

[Belo]

I would. Low RPM and slow flow is the way to run modern VS pump. Pipe size make les of a difference unless you have a spa that needs higher flows for spa jets.

Intelliflo3 is available at...

Pentair IntelliFlo3 VSF 3.0HP

All Intelliflo pumps require 240V. If you don't have that you can look at the Intelliflo i1 or i2 that run on 120V.

IntelliFlo® i1 and i2 Variable Speed and Pool Pump

The IntelliFlo i1 & i2 pumps move water more efficiently at lower speeds. They provide increased energy savings versus conventional pumps. Shop here!

www.pentair.com

That data exists because of the industry myth that you must turnover your water X amount of times per day. The amount of crud falling in the pool determines how much filtering you need, and will vary greatly throughout the season with more needed in the spring and fall and much less needed mid season.

Your own needs may vary from your neighbors if his tree crud blows your direction or vice versa.

The intelliflo i2 was designed for this exact scenerio.

So I'm a little frustrated by pentair's website. They link to a generic inteliflo manual so I'm unsure if the info is correct but it looks like the i2 still requires a 230v line. While I have a 20amp breaker on my box, I do not believe there's a 2 pole line out to the pool where I could rewire easily. This is what the manual on page 26 states anyhow https://www.pentair.com/content/dam...e-speed/intelliflo-vs-pump-manual-english.pdf

Also looks like it's also a 2" system. Appreciate the help!

 

[Bperry]

For the efficiency. A 3hp pump running at 1.5hp will be far more energy efficient than a 1.5hp running balls to the wall. You're correct that I do not need a 3hp pump and would likely never push it past 2hp.

True, but even with 1.5” pipes, you won’t need to run either pump at anywhere near the max speed. You should be running at the lowest possible speed to skim the water. The VS pumps are great in that the cost savings is huge by running lower speed. It’s so much of a difference that I run mine 24x7 and costs less than when I had a single speed pump running for 1/2 day.

 

[Belo]

True, but even with 1.5” pipes, you won’t need to run either pump at anywhere near the max speed. You should be running at the lowest possible speed to skim the water. The VS pumps are great in that the cost savings is huge by running lower speed. It’s so much of a difference that I run mine 24x7 and costs less than when I had a single speed pump running for 1/2 day.

Thanks and after a bunch of research this is my plan. The more I read and learned about inteliflo, I don't think it's tech that I need. I tend be a sucker for the latest greatest, but the way I understand inteliflo is that it's designed to maintain a certain gpm and will increase or decrease your speed based on buildup to maintain the level. I don't have any fountains or anything that would really warrant this as critical. It is still nice for a consistent filtration plan, but not critical for my needs.

Instead being able to program a 3 speed pump vs running my current 1hp pump on a timer will be a significant improvement and the superflo VS is about $700 cheaper and doesn't require new plumbing or electrical.

Thank you all for your help with me thinking out loud through all of this.