Help with my pump replacement please.

[mick1putt]

My 2hp Pentair Whisperflo pump is still flowing, but no longer at a whisper. It developed a loud whine last year that I assume is bad seal and bearings, so I've decided I might as well take the opportunity to upgrade to a 2 speed or VS system. I've read many posts here about pump size, and some of the Hydraulics 101 thread and my head is spinning. Please excuse my laziness for posting questions instead of searching for the answers, but I need some advice.

First some help with 2 speed or VS--I have a basic understanding of 2 speed and variable speed pumps, but not sure I understand all the benefits of VS. I've seen VS is best if you plan to "automate" your system. What exactly does it mean to have a fully automatic system?

Second, what about proper pump size? I've been told the 2hp Whisperflo is slightly oversized, no big deal, but if another size is better, now's the time to get it right. Pool is pretty straight forward, 20x40 33,000 gal ig. main drain and 2 skimmers, 6 returns, 2" pipe, Tagelus TA 100 filter (4.9 sq. ft. filtration area), no waterfalls or other features. I'm lost on the head loss thing, pool was installed in 2008 and I only have a vague idea of pipe routing, but will try to figure it out if someone can point me to a relatively simple formula.

Third, I'm using old school Kreepy Krauly and simple suction to clean. I'm seriously considering upgrading to some robotic cleaner (that will be another post later) will that affect pump decision?

Of course cost is a factor, but other important considerations are: noise (pump is right next to the house and just a few feet from screened porch), reliability, and easy installation and operation.

So far I'm looking at Pentair SuperFlo VS, 1 1/2 Horsepower, about $700, and Pentair 011018 IntelliFlo Variable Speed High Performance, 3 Horsepower, for about $900. Or should I just buy a 2 speed motor to bolt to my pump for less than $500?

Any opinions about these and any other suggestions are greatly appreciated.

 

[jimmythegreek]

If you are not using a SWG and no water features the VS is only worth it if your electric is expensive. If you are keeping the suction cleaner you need the power to run it as you have now. Ditch the cleaner and get a robot and switch your motor to a smaller 1hp or similar single or 2 speed.

 

[jimmythegreek]

Automation means programming your control box to do things for you. Turn valves, adjust water features and turn them on and off, run spa, etc. Big help with a SWG as you can run longer ti make chlorine and super slow to save money on electric

 

[Oly]

My opinion get the robot. I had the 2hp WisperFlo and installed the Superflo which is much better, quieter and is sufficient for my system. The Intelliflo is even quieter and being next to your house this is an issue. You probably can get by with a 1hp pump but it will always be running at a high rpm and noisy although not as bad as what you are experiencing now.

 

[mick1putt]

Thanks for the advice, I see a robot cleaner in my very near future; time to do a little research on them.

I said no other water features but I guess that's not entirely correct, I do have a SWG, and gas heater. I'm not sure I'd appreciate the value of a fully automatic system, it also sounds very expensive, and a lot of trouble switching out valves. I'm pretty happy with setting the timer to run the pump on whatever schedule I come up with, monitoring Cl and making occasional adjustments to SWG.

Noise is a big factor, maybe I notice it more since the pump is extra loud, but it would be nice to not hear it inside the house.

So, 1.5 hp should be sufficient for my pool?

 

[jimmythegreek]

You dont need that much pump. Which swg do u have and how do you control it and the pump? A 3/4 hp pump is plenty for a basic pool with no water features but may not be enough for a powered cleaner. This is where a 2 speed adds benefit in your situation with powered cleaner. You only run on high to clean otherwise you run low to filter and make salt. If you are gonna get a robot then you want a quiet smaller pump PBs usually install pumps too large for the application they dont pay the electric bill

 

[Oly]

After all my research it came down to a 2 speed or variable speed pump. I chose the vs because is gave me more options and programming the unit is simple with the controller built into the unit. Options are important because every pool system is different. You can determine the minimum speed required to operate your swg, heating system, suction cleaner and skimmer then adjust your schedule through the seasons. I'm guessing your cleaner will have the most demand of your pump speed. Now that I switched to the robot my max rpm is 2500 for skimming and ranges from 3 to 4 hours a day throughout the year.

 

[mick1putt]

I've got an AquaRite SWG, it comes on when the pump comes on, and the pump is controlled by a standard Intermatic switch. Mid season, when water temp is 85+, I usually run the system 10-12 hours a day (usually daytime) with SWG set around 75%. Electric rates are $0.2656/kWh peak and .0626/kWh off peak. I haven't done the calculation on how much $$ I'll save. The more I think about it noise, performance, and reliability are probably the most important factors for me.

I don't really use the heater much, just a week or so at the beginning and end of the season.

I think the Superflo might be a good choice for me too. I'm going to call Inyo and see if they can help me figure out the right size pump.

Got the approval from my wife to get a robot cleaner, so need to do some research on that one too. Sounds like that may allow me to go with smaller pump.

 

[mick1putt]

I just got off the phone with inyo pools, they said a 2 speed or vs may not be the best choice for me.

If I've done calculations right I need 55 gpm for 10 hour turnover, and I have about 55ft head (not 100% sure about that calculation, but I don't think it's off by a lot). I'd need to run a 2hp, 2 speed on high, or 3 hp vs would have to run at least 85% to give me 55-60 gpm. If that's the case I guess I might as well stick with single speed pump.

I was convinced 2 speed or vs was the way to go. What's wrong with this scenario? Am I missing something, or should I just go with the single speed pump?

 

[jimmythegreek]

you dont need turnover. that math is meaningless in my opinion. you only need the proper run time to make salt with your SWG. your flow and gpm are way more than the pump, the size piping, the layout of fittings, etc change all of those numbers. the old thinking of needing to "turn"water over is a myth. when your pool water is properly balanced the clean water is in contact with itself, thus its all clean and sanitized by your SWG. your skimmer and filter clean the particulates out of your water in conjuction with your cleaner/robot. I run my pool as little as 6hrs in the peak of summer at times and its sparkling I havent even turned half of my water over in a day. as longs as low speed on a 2 speed will satisfy the flow switch on the SWG you can run that all the time unless you need some power to quickly clean up with the skimmer or move the water around to help it. if you have the green light for a robot you will be all set I basically do nothing with my pool. I spend 5 minutes testing water every third day and maybe walk over to my automation panel and make an adjustment here and there. the most work I do is throwing the robot in the pool and plugging it in and then taking him out and cleaning the filters. I have the wife doing that now shes gonna learn how to test this year too

 

[mknauss]

proper run time to make salt with your SWG.

Just to be clear, a SWCG creates chlorine, not salt.

 

[jimmythegreek]

Brain freeze on my part. I own one lol

 

[mick1putt]

First of all, let me say, I don't really know what I'm talking about, I just keep trying to learn, and TFP is a great place for that, so thanks for the help. But...I don't understand how turnover is a myth.

I understand, it might not be important to turn your pool over in a certain number of hours, but isn't the amount a chlorine produced a function of how much water moves through the cell? A 33,000 gallon pool needs a certain amount of chlorine to sanitize, and since I'm losing chlorine everyday, I need to replace whatever is lost. Will the SWCG produce the same amount of chlorine in twelve hours regardless of whether it's flowing at 15 gpm or 55 gpm? Is the alternative running the system longer? Do I just turn it on and let it run 24/7 at a lower flow rate?

 

[mick1putt]

More to the point, what the heck size pump do I need?

 

[mknauss]

A SWCG generates a set amount of chlorine as long as you are pumping at a rate that closes the flow switch. The amount of chlorine it creates in a 24 hour day depends on the % setting you have and the hours you run it. It could care less how big your pool is.

Turnover is a myth because the water you are pumping is not segregated. You 're-circulate' a significant portion of the water each day. The chlorine disperses in water rapidly. So whether you put the chlorine in slowly with a SWCG or all at once with a bottle of bleach, the chlorine disperses in the whole body of water.

Your pump size depends on what you need it for. You do not show you have a spa or water features. So your pump at the minimum must have enough flow to skim the surface, close the flow switch on your SWCG, meet the minimum flow rate for your heater, and backflush your sand filter. Your current 2HP pump is way oversized, a much smaller 2 speed or a VS pump would work and consume less electricity and be less noise.

 

[mick1putt]

Ok, please be patient with me, I know I'm being a bit of a PITA now. I've been told twice, but still have a hard time grasping this concept.

I know the SWCG doesn't care what size the pool is, but are you saying the SWCG produces chlorine simply as a function of time and the % setting, and the volume of water isn't a factor, other than whats required to close the flow switch? For example, a SWCG set at say, 75%, running for 12 hours, produces the same amount of chlorine with 15 GPM running through it, as it does with 55 GPM? Or are you saying, I can turn the % up, and run it longer to produce the same amount of chlorine at 15 GPM as I did at a lower % and shorter run time, at 55 GPM?

I don't know how a SWCG works, in my feeble mind it magically uses the sodium chloride in the water to make chlorine (it's probably chemistry not magic, I just don't know the chemistry ). It seems the less water flowing through the cell, the less sodium chloride the SWCG has to work with, therefore it produces less chlorine.

The more I think about it, that doesn't make sense; if it is using the sodium chloride in the water to produce chlorine, wouldn't I have to regularly replace the sodium chloride? I think I need to read up on how a SWCG works.

 

[jimmythegreek]

Correct the cell produces the set % of output its programmed for regardless of the flow rate. The only requirement is that the cells flow switch is closed by the flow of water and then it works. If you look at VS pump curves theres a huge difference in energy consumption in regards to speed. I run at 1200rpms mostly just to make chlorine my pump equals a light bulb at that speed and is enough to operate the cell. You 2hp pump running at its speed is probably several lightbulbs worth of wattage and isn't necessary to just sanitize water. With a VS you can ramp speed up to run a heater, solar, spas, water features, or get water spinning in pool faster to skim faster etc. If you dont need any of that then low and slow is perfect to operate swg and save electricity.