What new pump do I need??

[JawJa]

Good morning Jim,

THX for the feedback... this pool thing is new to me... lots to learn!
I may need to modify my sig line slightly... I was told by the seller the pool is 40K gal... after measuring it repeatedly and doing the math... it comers out closer to 35K (including the SPA). Also... the solar arrangement is on a 2 story high roof... I am estimating the lift up 2" PVC and to the top of the slope of the roof is close to 30 ft. Finally... the pool is not really indoors... rather it is a metal/fiberglass enclosure over it... need to figure out how to post a cell phone pic... it is an ingenious custom built arrangement, with 6x 8ft square skylites that open!

The reason I posted all this information... is when I tried to calculate the TDH (head) and GPM...
I am getting a head of 70 and GPM in the 65 range...
Now if I remove the ~30 extra ft of head for not running the solar... I have a head back in the ~40 range... which seems more realistic.

I was looking at pump charts... and this is pushing the edge of performance data...
It would appear that running the VS pump with the solar engaged... would require to run the pump close to 3000 RPM's...
I am kinda hesitant to buy a $1000+ pump, designed to run at partial RPM's, and load it down to 80-90%+ of its rated operating ability... especially when the manufacturer is not gonna give me any warranty (DIY)...

Do you have any suggestions as to where to go with this...
Maybe use a VS pump for the pool and a booster pump for the solar?

THX for your input...
Perhaps I should start a new thread for this... it may get involved.

THX again... learning...
Grin

 

[Jimrahbe]

Jam,

Larger VS pumps move more water at lower speeds, that is why they are so efficient... I do not have a solar system so let me see if I can find some help in that area..

Calling @JamesW , @pooldv

Thanks,

Jim R.

 

[JawJa]

First, THX for having this forum available...
Being a new pool owner (bought the house with a pool), this forum is appreciated... lots to learn!
A word of introduction... I run a small heating and AC company... so the ability to figure out things, do electrical and plumbing, etc... is just another day of work for me. And since I am the only one in my family that is not a degreed and PE registered engineer... I tend to think like an engineer... grin! (Yeah, I know, that may well be dangerous... however I am not a )

I am working through understanding chemistry and getting the pool ready for my first swimming season... and pool parties... grin!
And as happens... the pump was getting louder and louder and louder... now it is sooo loud, I am concerned the neighbors are gonna complain...
Time for a new pump (note the old pump body is leaking... tried to repair it during the holidays... worked for a while... now it is leaking worse.

One of the really cool things about my pool... is the enclosure:
The pool is not really indoors, yet it is not really outside either: rather it has a metal/fiberglass enclosure over it... with sliding patio doors all around... with 6x 8ftx8ft square skylites that open! The skylites are an ingenious custom arrangement... albeit servicing the elec motor is kinda interesting... one has to do it from the roof... and if you drop a tool, it goes into the water... grin!
I was told by the seller the enclosure frame was acquired from a hotel remodel... there are tropical plants in the pool area that would freeze, they have not when the temps went down to 9*F...

Reading through this forum... learning about pool ownership and the ins/outs of maintaining a pool... I have gone through doing the plumbing math:
After a few times through the math (checking myself)...
I am getting a head of 70 and GPM in the 65+ range...
Now if I remove the ~30 extra ft of elevation from the solar in the calculation... I have a head back in the ~40 range... which seems more realistic.
The only thing I can find that may have thrown off my 'head calculation'... is the number of elbows and valves... some of this, of course, was estimated as it is in the ground.
Side note here... it seems to me (un-educated view)... that using long sweep elbows (rather than hard turn elbows) would cut down the static pressure (resistance to flow) in the plumbing. Yes, I know, the fittings at a big box store are for drains, not pressure... the joints would literally blow apart. It does seem like the pool industry would have a need for (and as such someone would make) long radius elbows and '45s' with joint surfaces for pressure applications...
That is another question for another time.

Back on the numbers:
A total head of ~70 when the solar is operating; and around 65-70 GPM's...
When I look at pump charts... this appears to be getting close to the edge of performance data...
It would appear that running the VS pump with the solar engaged... would require to run the pump close to 3000 RPM's...
I am kinda hesitant to buy a $1000+ pump, designed to run at partial RPM's, and load it up to 80-90%+ of its rated operating ability... especially when the manufacturer is not gonna give me any warranty (DIY)...

Do any of the 'PROs' have any suggestions for solutions for this issue???
Maybe use a VS pump for the pool and a booster pump for the solar?
Note other than the SPA... I do not have any water accessories... and do not have any plans for them.

THX for your input...
And THX for having this forum to learn!
Not all forums will go deep into the tech side of things... and it appears pool maintenance is something that (for me anyway) is gonna require I learn the tech side of it.

JawJa
(Reason for the screen name... is the forum will not allow 'GA'... which is my screen name at other forums)

 

[JamesW]

For a 1 hp Superflo, those performance numbers don't add up. See the pump curves for the Superflo here in the brochure and manual.

SuperFlo® High Performance Pumps

https://www.pentair.com/content/dam/extranet/product-related/product-brochures/pool-and-spa-equipment/pumps/SuperFlo_High_Performance_Pump_English.pdf

https://www.pentair.com/content/dam...gh_Performance_Pump_Owners_Manual_English.pdf

The filter pressure x 2.31 should be close to the return head. The suction head can be measured by a vacuum gauge or we can estimate it by your plumbing.

What is the filter pressure with and without solar?

What total percentage of time does the solar run?

How many solar panels and how much flow do they need?

 

[ajw22]

You need to have this discussion with @mas985

 

[Frank1026]

I would first like to ask for the Total Horsepower of your current pump.

Typically the details you are concerned about are already addressed by the PB or solar installer.
which means you should be just fine replacing the pump like for like including pot size.

Most VSPs are ~3hp
which will be more than likely higher than your existing pump
The VSP can be tuned down to work efficiently as possible with any given situation.

On the warranty concern as a DIY project and everything else given, i would recommend a Pentair Intelliflo 2VST.
This is one of the most reliable pumps on the market to date in my opinion. This pumps can also be programmed to operate on a GPM/Flow, the variable drive will automatically increase/decrease rpm to meet desired GPM.

and yes we do have sweep elbows

 

[setsailsoon]

Yes, I know, the fittings at a big box store are for drains, not pressure... the joints would literally blow apart

Jaw,

Welcome to TFP! Glad to see you're digging in to learn more about your pool I'll leave it to an expert to go through your head calculations. But I'd like to clarify a couple of things. Big box stores actually do stock sch 40 pressure pipe that are full sch 40 pressure-rated. They also stock (on the same aisle usually DWV which is rated much lower pressure so it won't pass building permit inspections etc. Also, at the heart of TFP is a system developed that is scientifically proven and also very easy to learn plus do without high-tech skills. We also do have a lot of very high-tech experts that can get as detailed as needed for any pool related problem... we even have really deep thinkers that hang out in the "deep end" forum.

For a simplistic approach on your pump question just look at the pressure gauge you have now with your solar running. That's the pressure drop required to overcome all the loss in your system at your current pump's performance curve. flow rate. This would be a good place to start when you look for pump performance on alternative pumps.

Hopefully one of the pump experts will be by soon to help on your pump head questions.

Again, welcome aboard!

Chris

 

[mknauss]

i would recommend a Pentair Intelliflo 2VST

That is a trade grade pump so you do not normally hear of it here on the forum. The Intelliflo VS 011018 is the gold standard of VS pumps available for purchase through online sellers.

Without automation there are a number of VS pumps on the market. Really depends on if you plan to DIY or not.

 

[pooldv]

I've been so happy with my Intelliflo and solar panels in texas that I'm going to do it all over again for our Florida pool. The Hayward VS pump went out the first month after we bought the house, thanks Murphy. So we've already installed the Intelliflo. I paid a oocal pool shop about 1400 bucks to install it because i wanted a 3 year warranty and someone to call to fix it if needed because we weren't planning to move there fulltime for about 10 months.

More about my pump, Solartouch and solar panels in my Texas pool thread, link in sig. Our Intelliflo drives the entire pool, waterfall, solar, heat pump all of it. pooldv texas pool thread

 

[Jimrahbe]

Jaw,

I believe that a VS pump at 3000 RPM uses about half the AC power that a single speed uses at 3450...

Let's see if Poolgate can show us his chart... Calling @PoolGate

Thanks,

Jim R.

 

[pooldv]

The way a VS or 2 speed pumps works is that it will move half the water and use a little less than 25% of the electricity half speed.

 

[mas985]

After a few times through the math (checking myself)...
I am getting a head of 70 and GPM in the 65+ range...
Now if I remove the ~30 extra ft of elevation from the solar in the calculation... I have a head back in the ~40 range... which seems more realistic.

There is 30' of head loss due to water rise in elevation but there is also 30' of head gain when the water falls back down through the pipe (assuming the pipe is full). So after the panels & pipe prime, there is no more static head loss.

The only thing I can find that may have thrown off my 'head calculation'... is the number of elbows and valves... some of this, of course, was estimated as it is in the ground.

Besides pipe and fittings, other head loss components are skimmers, main drains, valves, filters, heaters, SWGs, eyeballs, etc. Everything the water touches has head loss. Did you include everything?

 

[JamesW]

What is the filter pressure with and without solar?

Does the vacuum relief valve stay closed or do you get air in the returns?

How high is the vacuum relief valve?

How far away from the pool is the solar?

What size is the return line?

How are you calculating the head and flow because it doesn't match the curve for a Pentair Superflo (340038) 1 HP x 1.25 sf pump?

 

[JamesW]

We probably need to combine this with the other thread.

 

[mknauss]

We probably need to combine this with the other thread.

The threads were merged.

 

[PoolGate]

Here is my chart....

 

[JawJa]

WOW...
THANK YOU all for the responses...
Being a newbee to pools... I do appreciate all the information I can stuff in my head... grin!
I am a 'why' kind of person... when I understand the 'whys' behind something... it is easy to figure out what to do.
Rules without whys just do not work well in my head... grin!

OK, back on pools....
The idea of checking pressure at the filter with and without solar makes sense...
However...
Sadly... the pump quit yesterday... the motor still runs... however it will not prime...
I tried filling it with water... the water just runs back into the pipe from the skimmer (input to the pump).
(Note: in HVAC, we call it return and supply... so I am trying to not use terms that are familiar to me, yet may be wrong for pools).
Is there supposed to be some kind of one way valve on the line from the skimmer to the pump???

Where I am with it...
I cannot get the pump to prime... so I cannot read any pressures.
Not sure if there is something to fix... or if the pump has blown seals...
Or I need a new pump...
Or what???
What I can tell you... is the clear 'dome' on top of the strainer area at the input of the pump... leaks badly. I carefully cleaned the groove, wiped down the area where the O ring seals, and replaced the O ring... no help. It literally will lower the water level in the pool 1/2-3/4 of an inch in one day of running for 6 hours... not a good thing!
I am thinking new pump...

However before buying a pump... wanted to figure out which ones to get...

Someone asked about the solar arrangement:
*Panels are on a shallow slope roof (estimate 1/12 slope)... close to 30 ft higher than the pump. The feed and return are 2" PVC... the pipe goes about 2 ft down from the pump level, about 20~ ft horizontal, then up to the roof. The panels appear to be 4 ft wide... continuous row... I would estimate 12 panels given the roof dimensions (the panels go the entire area of that shed part of the roof). The feed pipes go up at the lower right corner of the panels (viewed from the top)... the supply goes to the top and far end, the lower end closer goes back in return. Solar is the last thing in the loop... feeds directly back into the pool (there is a valving arrangement to run the water up or bypass the solar).

My gut hunch is the solar is loading the pump too much...
Note that I bought the house last fall... the previous owners were kinda DIY types... and they do not seem to remember much...

The pump is a Pentair SuperFlo, Century motor says 1HP with SF of 1.65, 240V... 2" in and out.
Filter is a Hayward DE6020, with new grids in it!

Pool has a SWCG...

Someday, would like to do automation... however that is not in the budget for a few years.

THX in advance for any thoughts, ideas, or advise!

JawJa
Pronounced with a southern drawl.. dragging out the aw... grin!

Thoughts???

 

[mknauss]

Your current pump is OK you just need to get the pump basket to seal. I assume the oring is broken. You can replace it or get a new pump.

A VS pump is fine as is a two speed pump. Both are a good idea for SWCG. If automation is years off, I would not bother with that.

Inyopools has both VS and two speed pumps that are in house and provide a good warranty for DIY installs.
You cannot get too big of a VS pump. You just run it at the speed you need. A two speed pump should be sized at what you have now. The two speed will have to run on high to reach your solar heating.

 

[PoolGate]

I'll also add that your clear plastic top may be cracked. You can get a new one of those either. A cracked top would explain all of your issues. Without a properly sealing top the pump will not prime.

 

[JawJa]

THX for the replies...
I put a new O-ring in the pump (Pentair part)... did not help...
It appears there is a hairline crack in the pump housing... as well as the strainer cover not sealing.

IMO I need a new pump.

Specific question...
When calculating head... when adding the head for the solar... does one add the feet of rise from the pump area to the highest point of the solar on the roof???
An engineer suggested to me that yes the pump has to initially push the water up... however the water flowing back down the other pipe would create suction (sihpon), and counteract most of the head...
That just does not seem right to me...
THX in advance for a specific answer to the specific question....