Replacing pool pump - any recommendations?

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First, I thank you Mark, as I always have, for all the assistance you have given me with this matter. Second, I should not be made to feel that I need to apologize for having a thread that is lengthy or a topic/matter that is exhausting. I may suffer from analysis paralysis, but in order to make an informed decision, I owe it to myself to explore all concerns related to a pump/motor replacement. Never did I think that this topic would have led to a thread of this length. What I take from this is that a pump/motor replacement is a very involved decision that affects/could affect many different pool systems (i.e. main drain, solar, circulation, etc.).

I have perused the thread and do see that you are quite certain that the MaxFlo would work. I don't question that anymore. My last thread was simply to discuss new thoughts r/t to possible size differences of underground plumbing and any negative affect it would render on the pump/flow rate. It sounds as though it would only have a small affect on the flow. But, that is wherein my concern lies.

I did some investigating in my owner's file that has been past from owner to owner. I found the blueprint construction data on the pool. I have included a pic. I don't understand what it shows in the plumbing section. It appears that I do have 2" and 1.5" plumbing both on the return and suction side. For instance, on the return side, it shows 8'-90' of 2"-1.5". On the suction side, it shows 10'-19' of 2"-1.5". Whatever this means, it looks like I have some 2" and 1.5" plumbing. One comforting thing though is in the equipment section it shows that the original pump HP was 1.5. So, the 1.5 HP pump must have worked at one point over this pool's history. The pool was built in the '70s, but I don't think they had solar installed until some unknown later date.
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Prior to post #49, I gave you the specs. on my system. And, in post #49, you stated:
Without solar, your old pump would produce around 75 GPM and the MaxFlo (3000 RPM) would produce about 76 GPM. With solar and assuming 18 PSI, which seems a little high, the flow rate for your old pump would be about 59 GPM and the MaxFlo would be 55 GPM.
In post #53, you stated:
But because your panels are 288 sq-ft, you technically only need about 30 GPM for the panels. The reason the pressure rise is so high might be because you are forcing much more water through the panels than is necessary. With a VS, you will be able to set the flow rate so that there is only 30-40 GPM going through the panels. For the MaxFlo, this would be 1800-2100 RPM. But this might not be enough flow rate for priming so some trial and error might be necessary.

If the 1.5" plumbing would affect things, could it be drastic enough to reduce the flow of the MaxFlo, at 3000 RPM, to less than 30-40 GPM, which sounds to be the minimum for operating solar? Given this new information, how much lower than 55 GPM would the MaxFlo pump at with solar operating?
 
The filter pressure takes into account all of the return side plumbing so it doesn't matter what is actually there because it is already taken into account. The only guess is on the suction side and if that is 1.5" plumbing, the flow rate with solar with go from 55 GPM to 52 GPM. Not much of a change.
 
Tx Mark and n240sxguy.

Are the GPM estimates you provided proportional? If you estimate that 52 GPM would be the new flow rate with the MaxFlo and solar operating, would my old pump then be 56 GPM w/ solar operating?

Assuming 56 GPM to be the new flow rate, I calculated that on my pump 2600 RPM would produce 42 GPM. I am trying to determine if 2600 RPM could prime my system and be enough to run it.

In lieu of the Jandy 7305 after my filter, I was considering having the Flow-Vis 2"x2.5" check valve/flow meter installed.
http://www.amazon.com/FlowVis-2-5in-Complete-Flow-Meter/dp/B00JJ5HBUO
 
I replaced a perfectly good Hayward Super Pump with their Eco Star and am completely happy. The learning curve is not so bad and it delights me to see the pump running at around 400 watts at 2000 rpm instead of 2600 watts with the old pump. I do speed it up for massage jets, a small waterfall and when the solar panels are productive. I have not calculated the savings but think it will pay for itself in less than two years. I purchased it on line for about half the dealers price and installed it myself. The warranty is reduced to one year instead of three but what the heck. There is the Max Flo that is a medium head pump that is less pricy but it will not move enough water for solar. I have one sitting on my work bench that just didn't do the job but I still paid less than dealer price for the two pumps and I will sell the extra pump.
I need to try controlling it with my Pro Logic PS4 but that will be for a later time.
Bob
 
Yes around 56 GPM but are you reconsidering the VS replacement motor?

Also, priming is not guaranteed at 40 GPM. It might require more.

Why do you need a flow meter? Flow rate is not all that important. Your panels only need 30 GPM for efficiency and flow rate will need to be higher than that for priming and to determine priming flow rate, it really is a trial and error method to determine when the VRV remains closed and all the air is purged out of the lines. You cannot predict the flow rate to do that.
 
As for considering VS motor vs. pump, in some ways I am. My gut is obviously telling me something.

Last night, I was searching on TFP for info regarding VGreen 1.65 by Century. I saw this thread http://www.troublefreepool.com/threads/53713-What-is-the-best-variable-speed-motor-w-square-flange in which you had posted that you downsized your impeller and motor as it didn't make sense to go with a VS at the electric rates we pay out here. The replacement motor in my case would preserve my existing impeller/diffuser, but I would benefit from VS. Since I can't/don't want to do the install for a pump such as the Hayward MaxFlo, that install cost needs to be added in. If I go with a VS motor, then I will/may be able to do it myself and will save on the install cost. Therefore, despite the MaxFlo being approx. 10% as you stated Mark more efficient than the wet end of my Pentair Challenger 3/4 HP, I still have to overcome that install cost to break even. Install cost could be $400-500. But, the other way I look at it is what is the point of putting a new motor on my wet end if my wet end will always produce the same flow regardless of a larger motor? It is probably just 6 of one, half dozen of the other regarding pump vs. motor replacement.

As for the FlowVis, it is pretty much a Jandy 7305 type check valve with a flow meter attached. I thought this would be good b/c then I can see exactly what flow I need to keep the VRV closed. I was just going to have the check valve after the filter replaced at this time vs. the one after the solar. I guess what you are saying is that having the flow meter is pointless b/c I will still need to do trial/error to figure out what speed is needed to prime & keep the VRV closed, right? It just seems helpful to know what speeds cause what flow. Plus, while you don't advocate turnover, if I still cared to do it or calculate it, it would be easier with having the flow meter.

Last evening I went out to my smart meter to see just how much energy my pump is using. If I'm reading it right, it appears that it draws 1.560 kW. So, at $0.32/kWh, this thing is costing me $0.50/h. Crazy! The APSP Excel spreadsheet for pumps shows that the MaxFlo sp2302vsp pumps 53 GPM at 0.960 kW on Curve A and 32 GPM at 0.801 kW on Curve B. Mark, since my system is now most likely 1.5" plumbing underground, doesn't this mean that I actually would be getting the flows more representative of Curve B? I know you were saying there would not be that much of a change.
 
Curve A is representative to 1.5" plumbing. Curve C is closer to 2" plumbing. Nobody has Curve B except very old 1.25" plumbing.

Your approximate plumbing curve with solar is 0.01769 (close to Curve-A) and without is 0.00823 (close to Curve-C).
 
Well, I made a commitment to decide before I got to 15 pages :D, but you all could have a sigh of relief that I figured today was the day. I pulled the trigger and I have the MaxFlo sp2302vsp coming. In addition, the pool tech I am going to use is going to get me a GFCI breaker for the same price I can find online, and he will also get me the Flow-Vis check valve/flow meter for the same price. Install will be $550 for all three, prior to my rebate.

Thanks tremendously for all the help I have received here. Mark, I especially thank you for sticking it out with me. If you are open to it, perhaps we could meet up and I'll get you a beer or coffee. I appreciate all the light you have shed on this situation from pumps and motors, to main drains and solar. I have learned so much just through this thread alone. I will definitely be referring to it in the future.

I'll keep you all posted with the progress and post-install.
 
Of course I had to run some calcs to check the break even pt b/w an EcoTech & a MaxFlo. Remember, the EcoTech would keep the same wet end in my 3/4 HP Pentair Challenger. For this comparison I just used both pumps running at 6 hrs at 3000 RPM, since that is the limit for the MaxFlo. I used data from Hayward's energy calc vs. the APSP pump data sheets (although perhaps that would have given more realistic results). Hayward shows that the MaxFlo at 3k RPM uses 1.064 kW. The proportionate kW for my Pentair at 3k RPM is 1.357. At $0.32/kWh for 6h/day for 365 days resulted in an energy savings w/ the MaxFlo of approx. $205/yr. The pump install will be $400 of what I quoted previously. The cost difference b/w the EcoTech and MaxFlo, less my $100 rebate for the MaxFlo, is $125. So, the MaxFlo costs me $525 more upfront. This means it will take 2 yr 7 mo. to break even, and this is based on running at 3k RPM. I'm sure it will be sooner as it won't be at 3k RPM constantly.

This is not bad b/c 2 yr the manufacturer warranty ends, but then my credit card extends the warranty for another yr. Works for me.
 

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Few of those assumptions are realistic. The EcoTech with a 3/4 HP wet end would draw roughly half as much power as the MaxFlo VS when both are at the same RPM. Running at 3K RPM is the best case for payback, actual speeds are likely to be slower, and thus payback more slowly. And so on.
 
The Challenger pump would use about 1500 Watts with solar and close to 1600 watts without solar. The tricky part is the efficiency of the EcoTech but let's just say it is 10% more efficient than the Challenger as are most VS pumps at the same flow rate. That would put the power consumption of the hybrid pump at full speed at 1350 watts with solar and at 1440 without solar.

Now changing speeds is a little trickier because you have to take into account the power of the drive itself and the affinity equations. But most VS motor drives have about a 50-100 watt power offset. To match the flow rate of the MaxFlo at 3000 RPM, the hybrid pump would need a speed of 3200 RPM and not 3000 RPM. So this would result in energy consumption of 920 watts for the hybrid pump and not 1357 as you calculated. Also, the MaxFlo would actually use 940 watts on your plumbing with solar so not much of a difference in wattage as would be expected at these flow rates.

But what you are not including is the cost of replacing the EcoTech sooner than the MaxFlo. Just a guess but it is a risk.
 
Tx Mark & Jason.

I would have just assumed that my current Pentair would use 1.447 kW at 3200 as that is the proportionate amount based on my Smart Meter reading of 1.560 kW at 3450 RPM w/ solar off. Now if u say it is 10% more efficient than that simply shows me that it would use 1.302 kW at 3200 RPM. The APSP shows that the MaxFlo sp2302vsp at 3000 RPM on Curve A uses 960 kW and on Curve C used 1049 kW. I know u said I'm somewhwre b/w those 2 curves. I can't fathom how the EcoTech could even be close to the same kW as the MaxFlo at approx. similar RPMs.

If I understand u rt, u r saying to be more realistic it would be necessary to include replacement costs for the EcoTech since that won't have the longevity that the MaxFlo does, right? If that if the case I could just include another $425 assuming I will have to buy a 2nd EcoTech at maybe 8 yrs vs perhaps 10 yr w/ the MaxFlo.
 
I can't fathom how the EcoTech could even be close to the same kW as the MaxFlo at approx. similar RPMs.
Click to expand...
That is not what I said. I said they are about the same power at the same FLOW RATE. The RPMs are different because the wet ends are different. But one more thing to consider is that when you have the same flow rate on the same plumbing, the hydraulic HP is exactly the same between the two pumps. The only thing that may be different is the efficiency and that should be about the same too since both have VS motors. So it isn't surprising at all to me that the power is similar. It should be.

Also, power is not directly proportional to RPM. You have to use the affinity equations which is what I did. You cannot just scale by the change in RPM. It doesn't work that way.

http://www.engineeringtoolbox.com/affinity-laws-d_408.html

But you also have to account for the power offset of the drive (i.e. efficiency). So it is more complicated than what you are doing. The numbers I showed you take these factors into account and should be fairly close to reality.

Also your plumbing curve with solar is slightly worse that Curve A so it is not between Curve A and C. But slightly off Curve A towards Curve B. I think I posted this before but

Curve A is representative to 1.5" plumbing. Curve C is closer to 2" plumbing. Nobody has Curve B except very old 1.25" plumbing.

Your approximate plumbing curve with solar is 0.01769 (close to Curve-A) and without is 0.00823 (close to Curve-C).
Click to expand...
Curve-A 0.0167 and Curve-C is 0.0082
 
Yea, definitely above my pay grade figuring out those calculations :D Tx Mark for clarifying that. Had I known this info prior to getting ordering the MaxFlo, I may have gotten the EcoTech. But, as u stated, the reliability and questionable earlier replacement of the EcoTech are/were additional reasons to have gone with the MaxFlo.
 
Tech came out and got the install done of the Hayward MaxFlo sp2302vsp and a Flowvis check valve. Couldn't do the GFCI breaker b/c he had the wrong size. I am going to look around to see if I can order the proper one.

So far, huge difference with this pump. Much quieter first off. And, its great having the FlowVis. I love being able to see the GPM at each specific RPM. While originally you stated Mark that I could probably get away w/ 30-40 GPM for my solar as my panels at 288 sq. ft. only need about 30 GPM, I found that to be the case. You had estimated that most likely that would be b/w 1800-2100 RPM, but after some trial and error, I have found the sweet spot at 2400 RPM to be approx. 30 GPM when solar and Polaris is operating. Even at 2300 RPM, I was not able to keep the VRV closed. I didn't bother trying increments of 20 RPM b/w 2300 to 2400 RPM. It is great that this MaxFlo allows that flexibility to increase by increments of 20 RPM.

Right now I have it programmed during the day to run at 2400 RPM for 6 hours for solar, and at night time at 800 RPM. I found that things still work and the water is being filtered/skimmed even at 800 RPM. The FlowVis is showing that the GPM at 800 RPM is 15 GPM (and remember, this is w/out solar/polaris). It is awesome that at 800 RPM it is only using 49 watts (that is 0.049 KW). That is crazy! At 2400 RPM, I think it was using about 575 watts. According to my calculations, I am at about 40-45% energy usage of my old Pentair Challenger 3/4 hp. This is great! This is going to save me a bunch of money on my PG&E bill.

One thing I would definitely change with this version is to be able to have an override button to increase or decrease whenever I like. The only way to do it is to change a the specific program. Other observations at that the strainer basket is much smaller vs. the old one on the Challenger. So fa though, I am digging this little pump.

One thing I wanted to bring up though was that pump run time article on Pool School and also what either you (Mark) or Jason Lion stated in this thread that pools really only need about 4 hr filter time. It was never quantified at what RPM you were talking about. How can a pool only need 4 hr of filter/pump time if VS pumps can be run at all different RPMs? The GPM will be drastically different at let's say 2400 RPM vs. 800 RPM. Hence, 4 hrs. would not be equivalent as a starting point, or sufficient at a lower RPM.
 
Glad things are working out.

As for runtime, rpm doesn't really matter. For sanitation, only the first hour or two matter. After that it is just about clearing the debris so whatever rpm works is fine. If you don't have a lot of debris then shorter runtime is fine too.
 
Good news! Yes, VS pumps are great! You need to update your sig with your new pump info.

I think the assumption is you set the rpm for efficient skimming and then run it long enough every day so that your pool is consistently clean. For us we get good skimming at 1100 rpm, 150w, and solar is good at 1950, 450w.

On the pentair is you push the up arrow once it increases rpm by 5 and if you hold it down it increases by 50 rpm until you let go. Maybe similar for Hayward?

Congrats on the new pump and the success. And future congrats on your lower electric bill.
 
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