Why even buy a new pump?

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FLAK111

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Jan 28, 2018
60
North/Texas
*i may sound sarcastic, but not my intent, genuine request for thoughts and help*

So, i've done the research, i've done the math. I read and read that a new Variable speed pump will save me so much money in a year and over its life. I agree it would, but here are my delimmas.

First my set up:
-20x40 pool, avg dpth 4.5, total gallons rounding up 24,000.
-avg Feet of Head: 60
- current old pump (single speed, name brand Century, 1 hp, volts: 115/230, RPM 3450).
- DE Filter Hayward 4820
- Months pool used in year 8 - 9 depending on pool temperature ( i'll run pull pump slightly before pool season to help stop algea growth, true pool usage 5-6 months.
- peak watts used for whole house during heat of the summer (includes pool pump running a lot): 2600kwh. Average over 6 months: 2035kwh

General info:
A new pool Pentair Variable pool pump would be about 670 - 800 bucks and i can install it myself. Im looking at the SuperFlo VS, Model # 342001. On the diagnostics it is a 1.5 HP pump and has an max RPM similar to my current old single speed pump.

Questions:
Why cant I just buy an electric Transformer and switch so I can reduce the power by 1/2 and run my current motor at a lower RPM, therefore mimicking and making it a two speed. Do you think this would work?

If reducing the power by 1/2 on my current pump, wouldn't it therefor use less energy? Since it's a 1 HP pump, should I be concerned if it'll even move enough water for turnover and cleaning effectively?

When buying a new Variable Speed Pump, the flow chart shows it would take a little over 8 hrs to get 1 turnover at speed 1, but I get a little confused on how a variable speed pump will help when reading the flow charts, in example: speed 2 and 3, how do I use those for estimating turnover rate for my pool over time with my current set up?

Thanks for your time on my confusion and helping me clarify where I don't understand.
 
F,

Welcome to TFP... A great place to find the answers to all your pool equipment questions.. whether they sound sarcastic or not... :shark:

There is no doubt that VS pumps are not for everyone... The people that benefit the most are the ones that have high electrical costs and or run their pumps for extended periods of time. Another reason to own a VS pump is when you have the need for various water flow rates.. such as when running a waterfall or spa, etc.

For reference, my 3 HP IntelliFlo uses 180 watts of electrical power per hour at 1200 rpm, where it runs most of the time.. Your 1 HP pump uses 1,725 Watts of electrical power per hour.

The idea that you have to run your pump so that you get x water turnovers a day, is just not true. You only need to run the pump to satisfy the following reasons...


1. To keep surface debris moving and being pushed into the skimmers. The more debris the more often you need to run the pump.

2. If you have a Salt Water Chlorine Generator (SWCG) you'll need to run it long enough to generate the amount of chlorine needed.

3. To circulate the water to ensure the chlorine is effectively distributed throughout the pool. Two or three hours per day is all that is needed for this to happen in most pools.


Thanks,

Jim R.
 
A single phase ac pump cannot be run on a transformer, as they would be doing that already. I can always be wrong but I guarantee anything will not work.

Current methods for single phase ac variable speed drive cuts the negative side of the AC wave, equals half the power. Your motor is designed for it's speed, running it slower will overheat it.

You can buy a 3 phase ac motor and a vfd, but money.
 
Single speed, single phase AC motors are only single speed. If you feed them anything less than the voltage they require you will burn the motor up.

A variable speed motor and drive controller is far more complicated than just a transformer.

Dual speed motors have two separate windings in the motor to run at high and low speeds they do not alter the incoming power at all.

As others have said swapping your current single speed motor for a dual speed motor (and running on low speed) would save you about 80-90% of what a variable speed motor will save you on electricity.

For reference my superflo only used about 125-150 watts when running at 1200 rpm which is plenty of water flow for general pool circulation.

Check for utility rebates for switch to an energy efficient pump you may find your utility company will pay you a couple hundred dollars to upgrade your pump.
 
*mind blown* I did not know you could just swap out the motor end and get a motor tuneup kit. That reduces the cost about 30-40% (or more depending model of full namebrand VS being purchased). Thank you for the 411 on that. Do you know the member that has one?
 
I do flak...I upgraded my former Hayward max flow 1 hp motor for VGreen 1.65 hp that I purchased from Swimming Pool Supplies - Pool Parts - INYOPools.com.

If you look up the pump and post your plate info from your pump, they'll tell you whether you need the round or square flange.

I swapped it myself with hubby's assistance just so I'd know how to do it if in emergency I ever wanted to switch back to my single-speed. INYO has videos showing you how.

Mine has earned its keep already, but I'm running yearround and in winter 24/7 inside a dome where I have to keep water moving at all times. Let me know if you have any questions.
 
@ Swampwoman **and anyone else who wants to chime in: A few things: I looked up the VGreen 1.65 and called my local *knowledgeable +20 yrs of experience* pool company and asked them to validate my findings and thought processes. They said: With my current pool setup, ****see my original post** which I also have 1.5 inch piping, they do not recommend I get a VS pump at 1.65 HP. They didn't recommend it because, I would possible 1) after changing the motor, I would have other parts of the pump I would need to change out that are rated for 1hp, and upgrading to 1.65 means I may need to upgrade those parts of the pump **pump is estimating 10-15yrs old but works. So in essence, buying a VS pump $300-$400 plus other parts $100, would cast just shy of a new Pentair VS motor and pump at $680 ish. 2) having 1.5 inch piping, and a DE. Filter, they are worried about a blowing out my 1.5 inch piping when the pump is at max RPM with 1.65 HP, instead of the designed 1hp as currently set up. 3) they then said it may be a mute point to even change to a 2 speed, because, if I have two speeds, Max @3450 RPM, and low @1700 RPM, then I would need to run the pump 24/7 at the lower speed. This wouldn't save me too much money since if I ran full speed (like I do now) I would only need to run at about 8-10 hrs...in essence almost costing the same either way I go. Soooooooo, back to square one......any thoughts would help. Is it possible to cause harm to my 1.5 inch system with a 1.65 HP @ 3450 RPM vs my 1 HP @ 3450 RPM. ? any other variables are good discussions as well.
 

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**additional thoughts, So what I gather from various points of view is that: My pool company recommends not adding a VS pump to my system for possible blow out (at full RPM). Would this possibly damage my Haward DE 4820 filter.....I doubt it. The issues was the 1.5 inch piping they mention. Other people are saying I just need movement of water to acquire the 1 turnover (about) per 24 hrs. would this be gaurunteed at such a low speed of the VS pump running for 24/7 with 60ft avg of head? After talking to the pool guys in the industry, it knocked me off my horse that they recommended not to get one. Anyone want to counter this for my own learning curve?
 
I would recommend a variable speed pump. You can set the max speed to a safe speed right at installation.

Also, your head is not 60 feet. The head loss depends on flow rate. It's different for each flow rate.

And, turnover is mostly relevant for commercial pools. For residential, you just need to run enough to keep the water clear or generate chlorine if SWG.
 
I just changed from a single speed pump motor to a 2 speed pump motor. Mine was 1.5hp, but I'd imagine the savings are pretty comparable.

On my old pump, it ran at 10 amps at 230 volts. So 2.3 kilowatts per hour to run.

On the 2 speed pump, low speed is 1.6 amps at 230 volts. So 0.368 kilowatts per hour to run.

If I ran the old pump for 10 hours it would use 23 kilowatts. Running the new pump on low speed for 24 hours would use 8.8 kilowatts. That 62% less energy used despite the longer run time. In dollar terms, I pay about $0.10/kw. Old pump cost $2.30 to run for 10 hours, the new one $0.88 for 24. Per month, that's $69 vs $26.50, and I have really cheap electricity here.

I also don't know why you'd need to run the new pump for 24 hours. At most, you'd need to double the time your current pump runs (assuming the rest of the motor stayed the same, as the low speed will move 1/2 as much water as the high speed). Realistically, you can probably run it the same time as the old one and be fine.

After changing motors, I can't understand why they even sell single speed pumps anymore. I should have changed it as soon as I moved into the house.
 
I should also add that the new pump is -dramatically- quieter on low speed than the old one. I also imagine the lower pressures the low speed pump uses might reduce wear and tear on the rest of the pool equipment, but that's just a guess. So dramatically reduced energy costs, dramatically reduced noise, and maybe less maintenance in the future, all for about $350 and a couple hours of time.
 
Flak, I also have 1.5" piping. I virtually never run it at full speed but when I do my sand filter pressure isn't any higher than before. I also did not need to change my impeller when I changed my pump.

The VGreen IS a Century pump, and its max rpm IS 3450 -- my old maxflo was up rated.

In other words, my own experience suggests that your pool guys are all wet ;)
 
Swampwoman said:
Flak, I also have 1.5" piping. I virtually never run it at full speed but when I do my sand filter pressure isn't any higher than before. I also did not need to change my impeller when I changed my pump.

The VGreen IS a Century pump, and its max rpm IS 3450 -- my old maxflo was up rated.

In other words, my own experience suggests that your pool guys are all wet ;)
Click to expand...


Copy that. ty!
 
Your pipes will be fine. The most common configuration for pools in the past was 1.5 HP pump with 1.5" pipe. Not the ideal combo for energy efficiency, but it worked just fine.

Pool pumps for the most part can't generate more than 40 or 45 PSI no matter how you run them. That is, if you deadhead a pool pump (restrict the outgoing side of the pump to zero flow), it can pressurize the outgoing line up to around 40 PSI.

All the components are rated for higher pressure than the pool pump which keeps everything pretty safe. The pipe and fittings are rated for working pressures 4 to 5 times that much, and burst pressure ratings are around 20 times that much. A pool pump won't burst PVC pool plumbing that was installed (and connected) properly. If a joint never got glued it could be pushed apart, but that would happen at way less than 40 PSI.

When circulating pool water with a pump, you're overcoming friction in pipe and fixtures. When you slow down the flow, there's less friction, so far less energy is needed. Lets say it currently takes 6 hours of daily filtration at 800 watts to keep your water sparkling, and that consumes 4.8 kWh of electricity. If you circulate the water half as fast, the same amount of filtering will take 12 hrs. Due to the lower flow rate, you'll likely be able to achieve half the flow with one-quarter the power, or about 200 watts, so you will consume about 2.4 kWh of electricity (1/2 as much electricity to circulate the same amount of water). It may even be less time, because the filter will probably catch more debris with the water passing through it more slowly.

You may need to run the pump differently for water features, or skimming when it's windy, but the variable speed approach gives you the flexibility to achieve what you want at lower cost.
 
Just to pile on here I have a superflo VS and all 1.5" pvc pipe. Nothing has exploded or broken. You will never need to run it at full speed ever. That's what makes VS pumps great though, you get to pick what ever speed work for you and your pool.

There is a reason VS pumps only come in two HP ratings, its 1.65 or 3 HP, those two sizes cover 99.9% of all residential pools. With VS pumps the more HP you have the cheaper they are to run on low speed.

One thing your pool expert left out was the cost to change all the plumbing to the pump if your new pump doesn't fit exactly into where the old pump used to be. That can be a big cost saving when considering doing a motor swap vs. a all new pump. Despite their "20 years of experience" they have given you some poorly informed advice with a lack of understanding of how VS pumps work.
 

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