Do I need a variable speed pump?

Jump to latest Follow Reply
H

HofstraJet

0
May 31, 2011
96
Coral Springs, FL (near Ft. Lauderdale)
I'm doing some upgrades (SWCG, new lights) and the installer keeps telling me I should upgrade to a VS pump. I have a single speed 2 HP Hayward pump that works fine and am replacing the motor as it is getting loud (happens every 5-6 years). I have a simple pool with no water features and the pump runs a few hours a day to circulate and operate the Hayward Pool Vac. I did the math and it would take years to recoup the cost of the pump in electricity savings, not to mention that I don't even know when I would run the pump at anything less than full speed. Am I missing something?

Thanks!
 
A 2-speed would be a better option. Running a single speed, 2-HP pump just to circulate and filter water is a waste of electricity. A 2-speed on low would do the same thing for a lot less energy and you can use high speed for vacuuming.

A VS pump would allow you to control the on/off times and pump speeds more precisely. A very low speed setting on a VS pump (say <1000RPM) uses about as much power as two, 100W light bulbs.
 
JoyfulNoise said:
A 2-speed would be a better option. Running a single speed, 2-HP pump just to circulate and filter water is a waste of electricity. A 2-speed on low would do the same thing for a lot less energy and you can use high speed for vacuuming.

A VS pump would allow you to control the on/off times and pump speeds more precisely. A very low speed setting on a VS pump (say <1000RPM) uses about as much power as two, 100W light bulbs.
Click to expand...

Actually only ONE 100 watt bulb. My 3hp intelliflo use 100 watts @ 1,000rpm, 200 watts @ 1,500 rpm.

However, I agree that a two speed would be a more economical choice for the OP. Just replace the motor with a two-speed one and save about 1/2 or even more on your power consumption. No need for a new pump, just a motor and rebuild kit.
 
HofstraJet said:
it would take years to recoup the cost of the pump in electricity savings,
Thanks!
Click to expand...
That's says it all to me. I may be missing something too but I only hear about the cost savings. That issue has been decided for you. I was going to get a tankless water heater for my house when I did the math it too was years and years to recoup. If you were buying new maybe but to junk a working pump, I wouldn't.
 
A 2 speed pump will pump about half the water for about a quarter of the electric cost. Low speed is usually plenty for normal filtering, skimming, making chlorine, etc.

Like Chief I run my variable speed at 1100 rpm for skimming, filtering and making chlorine. It uses 150 watts and costs about 12 buvks a month to run my pump 24x7. We have lots of trees and often need continuous skimming.
 
HofstraJet said:
Thanks for the tips. A few questions:

Can I just replace the motor in my pump with a 2 speed motor?

Would a Jandy iAqualink recognize/be programmed for the two speed motor and allow me to control it accordingly?
Click to expand...

Yes you can replace the motor. Typically you get a new motor and a wet end rebuild kit as the impeller can be different for a two speed.

As for controls, I don't know Jandy but I know that Pentair requires the installation of special relay to control a 2-speed. It's a simple add-on for Pentair, I don't know how Jandy does it. You can probably call their technical support and ask.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006
 
Also, check with your electric utility. On some parts of the country, utilities will offer rebates to customers that switch to energy efficient pumps. If you can get a rebate, it might make a VSP financially attractive.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006
 
Yes, you can just swap the motor to a 2 speed, be sure to match the impeller to the new motor. Other motors usually use a switch mounted to the end of the motor to switch from hi to lo.
 
I run a single speed 2 HP pump for 6 hours a day in the summer. Based on voltage and current (amps) readings, I found out that the pump costs me about $20 a month to operate. My A/C on the other hand, sucks down far more electricity in the summer :(

I would like to replace my pump with a quieter and more effecient 2 speed pump, however I am patiently waiting my current one to break before I do that. I would also has to change out my Intermatic timer to run a two speed motor.

A variable speed pump is nice, but I've decided against them for several reasons:

Much more expensive than a 2 speed (even with changing out the timer).
More sensitive to power surges/spikes and lightning due to the amount of electonics in the motor controller
Most do not get along well with GFCI breakers

If your in an area with power quality issues, or a lot of thunderstorms, I would favor the two speed pump over a variable speed pump.
 

Enjoying this content?

Support TFP with a donation.

Give Support
When I switched to a VS pump I also added two "whole house" type surge protectors. One at my main electrical service panel and a second smaller one at the pool sub-panel. Now all my household electronics have protection and my pool equipment has double protection. Total cost about $150.

It was suggested that while the main panel provides primary protection for everything, the long wire run to the sub-panel can act like an antenna picking up lightning effect surges, hence the second one. We get a lot of lightning storms during Monsoon season.
 
Always thought how nice it would be if pool owners could temporarily and easily plumb in a demo VS or dual speed pump as a trial method of determing cost savings - but equally important IMO, how it performs with one's pool configuration (rooftop solar, suction side cleaners, spillways, waterfalls, etc - and various combinations of these).

For pro dual speed pump reasons already articulated on this forum, probably will go that route (here in San Diego, required to go with one or the other).
 
The cost savings depends heavily on your electric rate, and a VS really helps if you have a high rate.

My rate here is 9¢ a kilowatt hour which for my pump, a 2 HP single speed, only uses $20 a month running for 6 hours a day. It would take me a loooooonnng time to recoup the cost of a VS pump at that rate, which is why I'm in not particular hurry to replace my pump unless it breaks. And even then I'll be choosing a 2 speed over a VS since they are more rugged, will last longer, and is cheaper than a VS.
 
So after reading through this thread, my understanding is that you can't just simply replace a single speed for a two speed, it would require some type of control? I guess it would have to to know what speed to run at? Of all the things I've read about here I'm having the hardest trouble with electric motors. Right now I have three separate motors, all are simply either on or off. Good news is, for now they all work. I just want to learn what to do when the time comes.


Sent from my iPhone using Tapatalk
 
Lykly said:
So after reading through this thread, my understanding is that you can't just simply replace a single speed for a two speed, it would require some type of control? I guess it would have to to know what speed to run at? Of all the things I've read about here I'm having the hardest trouble with electric motors. Right now I have three separate motors, all are simply either on or off. Good news is, for now they all work. I just want to learn what to do when the time comes.


Sent from my iPhone using Tapatalk
Click to expand...

Simple response is this -

Single-speed pumps require a single source of electrical power. They are either 220V or 120V. The wire feeding them is a three conductor wire - hot (black), neutral (white) and ground (green). They can be controlled with either a simple mechanical timer (on/off switch) or relays on an automation panel.

2-Speed pumps require two powered conductors. The wiring on a 2-speed is slightly different as it uses what's called a 3-wire supply which is actually 4 conductors in the wire - two hots (black & red), one neutral (white) and one ground (green). Switch on one hot line and you get half speed from the motor (1725 RPM); switch on the second powered conductor and you get full speed rotation (3450RPM). These motors can be controlled with mechanical timer switches that are designed for 2-speed pump operation OR from an automation panel, usually with a special relay designed for 2-speed pumps. Some 2-speed pumps come with an on-board "HI/LOW" switch to make things easier.

Variable Speed pumps just need a single power supply (220V is pretty typical) and the conductor can be your standard 3 wires - hot, neutral and ground. The VSP's do all the speed control using on-board electronics. So many of them have a little 4 line LCD display on them with buttons that allow you to access all the features on the pump. These pumps can be run as stand-alone or with an automation panel. If they are run as part of an automation panel, there is usually two connections to make - power to supply the motor and a communications cable to run back to the automation panel (RS-485 or some other standard serial communication).

So, if all you have right now is a single-speed pump and a mechanical timer, then in order to run a 2-speed you might have to have new wiring pulled if there is not enough power supplied. In this case, it might be easier to simply go with a VSP, ditch the mechanical timer and use the on-board electronics of the VSP to control pump run times. If you have an automation panel, then there's a lot more flexibility.
 
Actually 220 has two hot wires, one for each phase.

Regarding the need or desirability of a VS pump over two speed or even single speed, a major consideration is the flexibility of a VS. I have a pool, spa and both have different flow requirements. Then there is the flow required by my SWG, and the solar heating system, oh yes, then there is the in-floor cleaning system. All these have their own speed/flow requirements and when more than one is used at a time, you can see that you may want many more than two speeds if you are trying to operate each at its best efficiency and function. Also the VS gives you the ability to program all your timing and speed changes right on the pump. Of course if you are using a sophisticated automation system, that could be a disadvantage or at least a bit of a challenge to integrate.

If my VS pump didn't save me a dime, I would still love it just for the programmability and flexibility.
 
One thing to be mindful of is will the low speed on your 2 speed keep your SW chlorinator full, I have a VS speed pump which would happily run at 800rpm but anything less than about 1200rpm the SWG cell housing wont stay full of water causing the low flow error and the whole thing shuts off...

I don't see this being an issue anywhere on the forum though...
 
Dibbler said:
One thing to be mindful of is will the low speed on your 2 speed keep your SW chlorinator full, I have a VS speed pump which would happily run at 800rpm but anything less than about 1200rpm the SWG cell housing wont stay full of water causing the low flow error and the whole thing shuts off...

I don't see this being an issue anywhere on the forum though...
Click to expand...

This is quite common in the sense that you can't always run everything at once. That's why many people opt for a VS pump and then use the scheduling and speed settings to run various functions - low speed for filtration, medium speeds for filtration and chlorine production & higher speeds to run solar heaters, in-floor cleaners and vacuum cleaners.

But you are right, an improperly sized 2-speed pump could mean not generating enough flow for an SWG. Always check pumping curves before you buy if they are available. Or, better yet, ask here on TFP as we have many pump experts.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply