I'm going to replace my pump and filter

[rowdy93]

Wow, First I'd like to say great write-up and knowledge. You have helped me a great deal and I appreciate the time you spent to put it all down for us.

Second, I was hoping I can get your input/help on what I'm working on. Here is my pool specs

16X32, Approx 21,000 Gallons
Pentair Pinnacle 1HP pump, that is going out on me
Tagelius TA-50 Sand Filter
Polaris 380 w./Boost Pump
Inline Clorinator
1.5" Pipe on Skimmer and 1.5" on main drain that goes to selector valve and 1.5" out of selector valve to pump and to filter
1.5" from filter that T's to feed booster pump
1.5" return lines that splits somewhere and goes to two return eyeballs
Only water feature is a fountain that is inplace of one of the return eyes

Since my pump is failing, I'm going to replace my pump and filter. I'm going to use the Pentair Quad DE and would like to use the wisperflow pump. I wanted a turn over rate of 4hrs, which I fiqured I needed to flow approx 90gmp. With the Quad 60 being a max 120gmp and ideal 90gpm, I fiqured that would be the one I needed. I have considered the Quad 80 at 160 max gpm but thought it may be to big and I may not be able to reach the ideal flow. Should I stick with the 60 or go to the 80?

Now the pump, with your tables I fiqured that I have a approx head of 45feet. With my 2-1.5" suction lines equalling a 2.1" line I'm fiquring I can reach my 90gpm goal. Also I was going to replace the line out of the selector valve to the pump and pump to filter with 2" line. The MPV i'm buying will be the 2". For the return I was going to use 2" and dig down at the pump pad and use a reducer to tap into the 1.5" line. My reason for this was trying to reduce the head and help the higher flow out, do you agree with this or should I just stick with the 1.5" return? As for the pump I was going to use a single speed because I didn't see the point of a two speed until I read all your info, so I'm now seriously considering the 2 speed. I was looking at the WhisperFlo WFDS-4 dual speed which will give me 100gpm @ 40ft of head or the WFE-24 single speed up rated which will give me 100gpm@ 40ft of head. I really want the dual speed because of what you said in your write-up but here's the problem I see with it: All of the 2 speed models have a max of approx 20feet of head on pentair's curve chart. Since I have approx 45feet of head, doesn't that mean that the pump will not move water on low speed? Am I missing something here?

Last question, should I use a flow meter on the new pump so I can figure out my turnover times?

I would really appreciate your, or anyones, help/guidance on this. I plan to hopefully buy on Tuesday 5 July.

Once again, awesome write-up and info. You have greatly increased my knowledge. Thank you
'

 

[rowdy93]

Re: Hydraulics 101 - Have you lost your head?

Happy 4th of July! Thanks to all of my fellow service members who put our lives on the line to give us our Freedom!!

 

[mas985]

Re: Hydraulics 101 - Have you lost your head?

Happy 4th of July! Thanks to all of my fellow service members who put our lives on the line to give us our Freedom!!

+1

I wanted a turn over rate of 4hrs

Why? Normaly, you don't want less than an 8 hour turnover to keep efficiency high. The ideal flow rate for a filter is basically an upper limit. Flow rates below the ideal flow rate will actually filter better and cost less to do so.

was looking at the WhisperFlo WFDS-4 dual speed which will give me 100gpm @ 40ft of head

I am not sure how you got to that number but based upon your description and assuming 25' runs from pool to pad, I would guess that the operating point of the WFDS-4 will be about 77 GPM @ 60' of head. On low speed, it will be 39 GPM @ 15' of head.

All of the 2 speed models have a max of approx 20feet of head on pentair's curve chart. Since I have approx 45feet of head, doesn't that mean that the pump will not move water on low speed? Am I missing something here?

Head loss in plumbing is dependent on the flow rate through the plumbing. Also, a pump's flow rate is dependent on the head loss in the plumbing. So the operating point is where the plumbing curve crosses the pump's head curve. At half speed, the pump will deliver about half the flow rate as full speed on the same plumbing system. Also, because of the lower flow rate at half speed, the head loss goes down by about 75%.


You might be better off with a WFDS-3 or 24. It is a smaller pump, will have a little less flow rate but the energy consumption is much less. The operating point for this pump on high speed, is about 73 GPM @ 50' of head and low speed is 36 GPM @ 13' of head.

 

[rowdy93]

Re: Hydraulics 101 - Have you lost your head?

Why? Normaly, you don't want less than an 8 hour turnover to keep efficiency high. The ideal flow rate for a filter is basically an upper limit. Flow rates below the ideal flow rate will actually filter better and cost less to do so.

I had read somewhere that you wanted a turnover rate of 4-6hrs at least once a day. Also I was trying to meet the ideal flow rate because it said "ideal". What you explained makes more sense.

am not sure how you got to that number but based upon your description and assuming 25' runs from pool to pad, I would guess that the operating point of the WFDS-4 will be about 77 GPM @ 60' of head. On low speed, it will be 39 GPM @ 15' of head.

I had used the pump curve from the WFE-24 since I could not find the curve for the WFDS-4. Used that one because the pumps were similar and on the curve it showed 100gpm @ 40.

Head loss in plumbing is dependent on the flow rate through the plumbing. Also, a pump's flow rate is dependent on the head loss in the plumbing. So the operating point is where the plumbing curve crosses the pump's head curve. At half speed, the pump will deliver about half the flow rate as full speed on the same plumbing system. Also, because of the lower flow rate at half speed, the head loss goes down by about 75%.

That makes alot more sense to me!

You might be better off with a WFDS-3 or 24. It is a smaller pump, will have a little less flow rate but the energy consumption is much less. The operating point for this pump on high speed, is about 73 GPM @ 50' of head and low speed is 36 GPM @ 13' of head.

Product Model Voltage Full Load Amps HP SF SFHP Primary Listings and Certifications3 Port Size (NPT) Carton Wt(Lbs) Curve Key
012485 WFDS-24 115 14.6/4.7 1 1.25 1.25 UL1, NSF2 2" x 2" 42 A, F
012518 WFDS-26 230 7.8/3.0 1-1/2 1.10 1.65 UL1, NSF2 2" x 2" 47 B, G

Was going with the -26 because it had lower amperage, so i thought that it would be lower energy usage. Is that wrong?


Quad 60 or 80, only bennefit i was thinking with the 80 would be less cleaning. Any other reasons to go with one or the other?

Do you agree with my plans for the pluming? 2" suction from selector valve and 2" to pump and then 2" return reduce to my existing 1.5" thats under concrete.

Flow valve or waste of $$$?


Thanks again for your time spent

Seth

 

[mas985]

Re: Hydraulics 101 - Have you lost your head?

I had read somewhere that you wanted a turnover rate of 4-6hrs at least once a day.

Maybe for a commercial pool but for residential, you really only need a 8-12 hour turnover.

had used the pump curve from the WFE-24 since I could not find the curve for the WFDS-4.

Actually, the WFE-24 is the same head curve as the WFDS-3 and the WFDS-24. The WFDS-4 has the same head curve as the WFDS-26.

Was going with the -26 because it had lower amperage, so i thought that it would be lower energy usage. Is that wrong?

The 26 is a larger motor and uses more power than the 24. Note that the 26 is shown as 230v while the 24 is 115 volts so the wattage of the 26 is higher than the 24. Plus the amps on the label is only a rating for the motor and does not reflect the actual amps in service. The actual power usage will be dependent on the head loss in the plumbing. With your plumbing, the 24 will likely use around 1573 watts while the 26 will use 1858 watts.

Do you agree with my plans for the pluming? 2" suction from selector valve and 2" to pump and then 2" return reduce to my existing 1.5" thats under concrete.

Yes, as long as your are replacing the plumbing, you might as well upsize it a bit.

 

[rowdy93]

Re: Hydraulics 101 - Have you lost your head?

Note that the 26 is shown as 230v while the 24 is 115 volts so the wattage of the 26 is higher than the 24.

Man I can't beleive I missed that detail, must of been half asleep. I'm going to use the WFDS-24. I chose the 24 over the WFDS-3 because its $72 cheaper for the same price.

I'm not going to use a flow meter because once its all in place, I can just calculate my flow to fiqure out my turnover times.

Before I have found your post I had gone to my local pool store to get my answers, well they didn't seem too informed, so I did my own research. Let me say that you have helped a great bit and are well informed.

Last question! I had asked pool store, Quad 60 or 80, they told me if I went with 80 that I would need to go to a bigger pump. They said either a 1 or 1.5hp. Well after reading and talking with you, that doesn't seem quite true. I would like to go with the 80 because it seems like it would be more efficent because it would take longer to flow trough then the 60. To me, wether I use the 60 or 80, I would be able to use the WFDS-24 pump. Am I thinking on the right track here? Which would you go with and could you explain?

Thanks again, I appreciate this

Seth

 

[JasonLion]

Getting the larger filter is better. You will be able to go longer between backwashings/cleanings, have just slightly better filtering, and a slightly more efficient system overall.

 

[rowdy93]

By going to the larger filter will I be able to still use the wfds-24 or do I have to go to a larger pump like my local pool store said. I dont see why filter size matters to pump size.