Variable speed, cost savings/ filtration?

[Metalman23]

I'm considering a variable speed pump for next season, I'm running the numbers and it'll cost me an extra $85/month (running 10 hours/day) at my current electric rate to run the single speed that I have now. Now a unit like this PureLine 1.5 H.P Variable Speed Pool Pump - PL1615 - INYOPools.com

says it draws .15 amps at 750 rpms, that is such a dramatic savings it'd be stupid for me not to buy it .15 amps @ 240v is 36W which is less than a light bulb. That would only cost an extra $5/ month to run it (24hrs/day)

Now from the electricity perspective it makes sense, but can that keep my pool clean at only 750 rpms? About 1/4 of the full speed pump? Who here has a variable speed pump, and what is your experience with it? I'm interested to know hwo has expirimented with the lowest flow rates on VS pumps and what the results are?

I don't know if INYO sells good pumps, that one is significantly cheaper than the Hayward pumps

 

[mknauss]

You will likely have to run it closer to 1500-1750 rpm to achieve the circulation to skim effectively.

But, it still will use far less electricity.

What is the HP and SF of your current motor? What is your normal filter pressure?

 

[markayash]

That's the pump I have, I replaced a 1.5hp super pump 2. Just comparing my power bill this year vs last it went down around $45 a month and it was hotter this year..I run my pump 24x7 in the summertime around 2100 rpm's. I have a hot tub and a water fall so need 2100 for good water flow.

 

[VirtualChris]

...

 

[Metalman23]

You will likely have to run it closer to 1500-1750 rpm to achieve the circulation to skim effectively.

But, it still will use far less electricity.

What is the HP and SF of your current motor? What is your normal filter pressure?

Pressure is 12psi I haven't run the pool long enough to know what's normal.

SF is 1

It's a 1hp

 

[mknauss]

Your current pump uses about 1kw per hour it is run. I suspect the small vs pump you show will use 250-300 watts per hour to get sufficient flow to maintain your skimming requirements.

You do not say if you use an erosion trichlor feeder. If you do, you will need to run the pump faster to achieve what your getting now.

 

[Metalman23]

Your current pump uses about 1kw per hour it is run. I suspect the small vs pump you show will use 250-300 watts per hour to get sufficient flow to maintain your skimming requirements.

You do not say if you use an erosion trichlor feeder. If you do, you will need to run the pump faster to achieve what your getting now.

The pump says it draws 6 amps , so I figured 1.44 kw, but either way, 250-300kw would be a 75% (or so) savings

I do not use a trichlor feeder, I add bleach manually, eventually I want to get a salt cell. (also next season)

I do want to add a heater as well, that I might add this season as the summer is starting to wind down.

 

[mknauss]

Check into a two speed motor to replace just your current motor. You will get the bulk of the electricity cost savings but not have the electronics of a VS pump that can fail.

Call Inyopools. See what they suggest.

 

[DuaeGuttae]

I just wanted to mention that you should also look into possible rebates from your power company. We replaced a 3hp single speed with variable speed, and the power company gave us a significant rebate. The energy savings is impressive as well. I run at 1800 rpm to get better skimming action as I have lots of trees.

 

[newdude]

On top of the possible rebates, a larger pump will use less power to move the same amount of water. Even if it takes 3 half seasons to pay for itself, it will literally make you money the rest of the time. Most people don’t want to bite the bullet and spend more than they absolutely have to, but if you are able to afford it, it will reward you many times over.

 

[laprjns]

a larger pump will use less power to move the same amount of water.

I am having a little problem wrapping my head around this. Could you please explain what you mean by "the same amount of water".

 

[mknauss]

A 3 hp VS motor and pump will pump the same gpm at a lower rpm than a 1.65hp VS pump. So there will be less electricity used to pump the same rate of water.

 

[newdude]

Not sure if you were already oversized. If you weren’t, now is the time to go one step up.

 

[laprjns]

A 3 hp VS motor and pump will pump the same gpm at a lower rpm than a 1.65hp VS pump. So there will be less electricity used to pump the same rate of water.

I agree with your first sentence, but not your second. It is going to take the same amount of horsepower to move the same flow through the same plumbing system, no matter the rpm. Same horsepower, same electricity.

 

[RMcGirr83]

Typically, and I may be wrong, larger size pumps have larger size impellers, ergo, move more water. It's the impeller that moves the water.

 

[TBSNPS]

Why are you running your pump 10 hours daily?? I'm just trying to learn, I read the pool school article on pump time and reduced my run time,3 hours daily is all I need for a sparkling clear sanitized pool.

 

[markayash]

Now that i have a VS pump not using so much power I run mine all the time. Like the water fall sound, was out here at 3am

 

[Metalman23]

Why are you running your pump 10 hours daily?? I'm just trying to learn, I read the pool school article on pump time and reduced my run time,3 hours daily is all I need for a sparkling clear sanitized pool.

I'm trying to find the least amount of time I can run the pump and keep the water clean, the 10hrs was just a scenario, I may not need it to run that long, I'm new to pool ownership so I'm learning as I go here.

 

[Metalman23]

Also I'm going to either be running a liquidator or SWCG eventually so the pump will need to be running in order to chlorinate the water.

 

[laprjns]

Also I'm going to either be running a liquidator or SWCG eventually so the pump will need to be running in order to chlorinate the water.

I ran a Liquidator for six years and was happy with it but I can tell you that it's not going to work with a VS pump running at low speed. I suggest that you go directly to the SWCG. I changed over to a SWCG and VS pump this year and now wondering why it took be so long to switch.
Regarding the pump size, if you are happy with the flow rate that you are getting with with your current pump and don't need any more then get a VS around the same size. Going to a bigger VS is not going to save you anything over a smaller VS. Running a 3hp VS pump and a 1.5 hp VS at the same flow rate that your current pump puts out is going to take the same horsepower, that is 1Hp. If you don't need or want more flow then oversizing your pump just get you more horsepower that you will never use.
Even though I said to get the same size pump, I not sure that there are any 1Hp VS available. You might want to go with either 1.5 or 1.65 hp.