Is a 1/2hp Whisperflo is better than 3/4hp Superpump?

[kevreh]

May need to replace my 3/4hp Super Pump (Hayward). I know its equivalent is the Superflo on the Pentair side, but was looking at the Whisperflo too. Interestingly, looking at the GPM curves, the 1/2hp Whisperflo gets better GPM than the 3/4hp Super Pump. For example, at 30 head feet of water, the Super Pump moves about 55gpm while the Whisperflo moves (what looks like) about 75gpm, based on the charts linked to below.

Am I reading this right? I could save quite a bit of power by going with the Whisperflo. Conventional wisdom is that a 1/2hp pump is too weak for my pool (24k gal in ground) but hey, they charts don't lie! Or do they


http://www.poolcenter.com/pentair-whisperflo-pool-pump-DS.pdf
http://www.poolcenter.com/hayward-super-pump-DS.pdf

 

[mas985]

In general, the lower the head curve, the better the Energy Factor (gallons/watt-hr). So smaller, lower head curve pumps will usually cost less to run. Since the Whisperflo produces more flow rate, it will use more energy to do so. However, the Energy Factor of the Whisperflo WFE-2 is slightly higher than the 3/4 HP SuperFlo (no data on the 3/4 HP Superpump) because it has a higher efficiency motor but it is only about 5% better so not enough really to justify the cost difference. But if you are really interested in reducing energy costs, I would just replace the motor of your current pump with a two speed. You would save about 50% in energy costs on low speed vs high speed and/or the Whisperflo single speed and would cost far less to replace just the motor than the entire pump.

 

[kevreh]

Hmmm. I'll have to look into that a little more to understand what your saying. 2 speed pumps are a big jump in price. How many hours a day do you use the high speed vs. low speed? How do you know the low speed gives you enough turnover?

BTW, I'm having a hard time finding the power usage on Superpump and Whisperflow. The only thing close is that the Whisperflo 3/4hp uses 10.8amps at 115v full speed. Would be nice to see what the 1/2hp Whisper and 3/4hp Superpump use.

Thanks Mark

 

[mas985]

2 speed pumps are a big jump in price.

Yes but like I said before, you don't need to replace the entire pump, only the motor which is significantly less.

How many hours a day do you use the high speed vs. low speed?

Depends on the time of year but usually around 2 hours low speed and 2 hours high speed for the vacuum. Some people get away with running only on low speed, it just depends on your own situation.

How do you know the low speed gives you enough turnover?

Low speed is half the flow rate so you need twice the run time. However, it uses 1/4 the power so overall, you save about 50% in energy costs.

The California Energy Commission (CEC) published measurement data from many different pumps. You can go to their web site and download the data but you need to know how to interpret the data. Also, some of the data is incorrect, I cover some of the issues in this post:
hydraulics-101-have-you-lost-your-head-t915.html#p6544

The CEC web site is here: http://www.appliances.energy.ca.gov/AdvancedSearch.aspx

But I also, have a copy here: https://docs.google.com/spreadsheet/ccc ... vOUE#gid=0

 

[kevreh]

Nice spreadsheet! Thank you! I looked into replacing just the motor. Its not bad price wise, but unfortunately doing so means I'll have to buy a ~$125 two speed relay for my Suntouch controller. So bummer. But if I do some calcs I guess I can see how long it would take to make that back, coupled with the price of the 2 speed motor.

 

[mas985]

Check Amazon, I think they are a little cheaper. Another option is a manual switch but not as convenient.

http://www.amazon.com/Pentair-520198-As ... B001DO6S26

 

[UnderWaterVanya]

Nice spreadsheet! Thank you! I looked into replacing just the motor. Its not bad price wise, but unfortunately doing so means I'll have to buy a ~$125 two speed relay for my Suntouch controller. So bummer. But if I do some calcs I guess I can see how long it would take to make that back, coupled with the price of the 2 speed motor.

Is that because you have an automatic cleaner hooked up all the time? Otherwise you can just add a manual switch on the back of the pump for now and manually switch to high speed when required for vac etc.

 

[kevreh]

I do have a Polaris 280 cleaner, with its own booster pump though. That has its own relay in the Suntouch to turn on independantly.

Mark, you said that "Low speed is half the flow rate so you need twice the run time. However, it uses 1/4 the power so overall, you save about 50% in energy costs." The 50% energy savings is appealing. Also nice is that the low speed pump is a lot quieter from what I hear. Since our pump pad is about 10' away from the pool thats a nice perk.

Couple tangential questions, if I haven't pushed my luck yet :-D ;

- How do I figure out my target turn over, and how does pumping water up 20' to my solar panels and down again affect head pressure/flow rate?
- How is it that its 50% the flow rate but 1/4 the power?
- Mark, you also said: "Depends on the time of year but usually around 2 hours low speed and 2 hours high speed for the vacuum." Since I have a booster pump for my Polaris, could I not even wire up the high speed, use low all the time, and run longer?
- Can anyone find the power usage for the Hayward Superpump, 3/4hp at 115v?

Maybe to ease the pain, I could spread out the new relay and two speed pump purchase over the winter since I'm closing down for the fall this week.

 

[UnderWaterVanya]

- How do I figure out my target turn over, and how does pumping water up 20' to my solar panels and down again affect head pressure/flow rate?

Some additional detail like plumbing size, number of suctions and returns, etc will help Mark give you better detailed info on the flow rate - which you can then use with your size to determine the turnover rate.

- How is it that its 50% the flow rate but 1/4 the power?

The trick is that at a lower speed the head loss is drastically reduced which means that you lose less flow than normal - which gives you more flow for less power.

- Mark, you also said: "Depends on the time of year but usually around 2 hours low speed and 2 hours high speed for the vacuum." Since I have a booster pump for my Polaris, could I not even wire up the high speed, use low all the time, and run longer?

I have seen threads were some claimed they used a booster pump and a two speed pump on LOW but I cannot confirm or deny that this works. If it does work I don't think the runtime will actually need to be longer.

- Can anyone find the power usage for the Hayward Superpump, 3/4hp at 115v?

Punt! No idea.


Maybe to ease the pain, I could spread out the new relay and two speed pump purchase over the winter since I'm closing down for the fall this week.[/quote]

 

[mas985]

Pump affinity laws influence power usage:

GPM B = GPM A * (RPM B / RPM A)

Head B = Head A * (RPM B / RPM A) ^ 2

Hydraulic HP B = Hydraulic HP A * (RPM B / RPM A) ^ 3

But because the motor efficiency drops by 50% on low speed, instead of 1/8th power, you only get 1/4th power.

I would use the Superflo as a proxy to the Superpump. Head curves are similar and motor efficiency is similar. On typical 1.5" plumbing (Curve-A), the Superflo has the following operating points:

High Speed: 47 GPM, 1114 Watts, 2.53 EF
Low Speed: 24 GPM, 280 Watts, 5.14 EF

 

[jblizzle]

Just wanted to add that you may not be able to run the solar on low speed ... Certainly not prime with it. Just wanted to make sure you understood that. Solar heats more efficiently at higher flow rates anyway.

Seems like your setup would be best to run on high speed for the cleaner and when you want solar. Then low speed for the rest of the time ... most of your power savings will likely happen when you are out of season and not needing the solar.

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[kevreh]

Just wanted to add that you may not be able to run the solar on low speed ... Certainly not prime with it. Just wanted to make sure you understood that. Solar heats more efficiently at higher flow rates anyway.

Seems like your setup would be best to run on high speed for the cleaner and when you want solar. Then low speed for the rest of the time ... most of your power savings will likely happen when you are out of season and not needing the solar.

Posted from my Droid with Tapatalk ... sorry if my response is short

Yeah, I just read the 4 pages of hydraulics 101 thread mark started. The issue of having enough pressure to prime the panels gave me concern. Mark, if I give you a description of my system can you estimate whether a 3/4hp ao smith pump on low speed will work?

Jason, why high speed with cleaner if I have a booster pump?

Thanks!

 

[jblizzle]

Oops you are right. Booster pump does not need high speed.

So you could likely use low speed all the time except when running solar ... Although Mark can confirm the solar concern. Personally I had no assumption that I could run my solar on low and resigned to saving money when solar is not used.

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[kevreh]

The good thing with the Suntouch is that you can have it direct flow to the solar panels when the temp at the panels is x degrees greater than the pool water. I'll have to see if there's a way to tell it to switch to high when re-directing through the panels.

Have you tried running on low speed through your panels?

 

[mas985]

The good thing with the Suntouch is that you can have it direct flow to the solar panels when the temp at the panels is x degrees greater than the pool water. I'll have to see if there's a way to tell it to switch to high when re-directing through the panels.

Most controllers will switch the pump to high when using solar whether you want to or not. In fact, it is actually harder to force a controller to leave the pump on low speed unless you have a VS pump.

There are several issues with using solar on low speed.

1. - Not enough flow rate to prime the panels. This is probably the biggest issue but can be overcome by priming on high speed and running on low speed, assuming the controller supports that.

2 - Keeping the vacuum release valve (VRV) closed. Normally the VRV sits near the highest point of the panels so fairly high pressure is needed to keep it closed. Only high speed will have enough pressure to keep the VRV closed on a two story roof. However, you can get around this by dropping the VRV down to a lower height so less pressure is needed. But then even more flow rate is needed to prime the panels.

3 - Lower flow rates reduce solar panel efficiency so pool water won't get as warm as quickly.

If the controller supports #1, the VRV is placed in the proper location and you don't care about efficiency, then it may be possible to run on low speed.

 

[kevreh]

Thanks for all your guidance Mark. Indeed, with the Suntouch controller there are a number of features that help to control the low/high speeds of the pump. First it looks like when the pump comes on theres a 5 minute delay where it starts on high then switches to low. Also, it looks like you can switch the pump from low to high when certain circuits are activated (ie. heating, solar, etc...).

Soooo....plenty of options on how to set this up.