Please recommend a fountain pump

bobdobalina · May 5, 2015

Hi. I have a fountain and I am considering a new pump as the old pump is probably pretty inefficient and electricity rates are now in the high 20s per kWh.

Considerations:
1. Existing pump is 1/2 HP.
2. Pump is ~6 feet above the water level in the fountain.
3. Presently have a small suction side leak that is underground. No problem running but self-priming doesn't happen after the pump has been off for more than 6-8 hours.
4. For reasons in #3, a variable speed pump that would let me dial it way down at night would be a nice feature.
5. Two-inch piping all around.
6. I'd like maybe a bit more available power (for a taller spray).
7. I am concerned about energy costs

Is there a clear favorite for my needs?
Thank you.

mas985 · May 9, 2015

Is this a stand alone fountain or is in the pool?

bobdobalina · May 12, 2015

mas985 said:
Is this a stand alone fountain or is in the pool?

It is a standalone fountain.

mas985, you are the resident pump guru, right? The EnergyStar spreadsheet is blowing my mind. This is complicated!

mas985 · May 12, 2015

Then you are probably better off using a submersible fountain pump but you may not get many suggestions on this fourm. Try gardenweb.

Were you think of using a pool pump?

bobdobalina · May 12, 2015

Oh, no. The fountain is separate from the pool but it is plumbed with Schedule 40, it shares the pump pad with the pool, has a brominator and an Aqua-rite (pool-style) filter. It currently has a 1/2 HP Whisperflo.

I mean, it's designed to work with a pool pump. Not a $100 fountain pump or a $5,000 fountain pump. A bog-standard pool pump.

mas985 said:
Then you are probably better off using a submersible fountain pump but you may not get many suggestions on this fourm. Try gardenweb.

Were you think of using a pool pump?

mas985 · May 12, 2015

Ok, so all of that is important background so I know what you are after here.

But here is the problem, energy use has a very high correlation to flow rate (~ GPM^3). So if you want to save energy with a fountain, you will need to accept lower flow rates and less height for the fountain. Is that ok?

BTW, the Whisperflo is a very efficient pump for the flow rate so you won't get much better than that. A VS pump would give you a bit more efficiency but at a huge cost so I doubt you would be able to pay for the pump with the energy savings.

bobdobalina · May 12, 2015

I think it would probably be best to get something adequately programmable so I could run it at a very low speed ~20 hours per day and run it hard for ~4 hours per day. I believe you, but I am surprised my existing pump is relatively efficient. It looks pretty old and it is noisier than the newer pumps on the pad which run at higher HP. It would help to have data on the existing pump so I can perform an actual economic assessment. But that doesn't exist.

As I play around with my own spreadsheet I am surprised how close so many of the pumps sit to the regression line. When one finds the bigger outliers, he can't help but wonder what the standard error in the EPA's test procedure is. And I also wonder why they don't distribute more data throughout the pump curve-- the variable costs of doing so are trivial compared to the fixed costs of getting the pump on the bench and setting it up, I would imagine.

Anyway there doesn't seem to be the perfect pump out there The Ecostar and the SuperFlo VS seem very efficient in the low-speed environment (perhaps their electronics have the least overhead?) while the Tristar looks to be the best pump for the four-hour hard run. But I can only reach that conclusion because most of the 3450 RPM pumps lack mid-range data.

Anyway thanks for your help.

mas985 · May 12, 2015

It would help to have data on the existing pump so I can perform an actual economic assessment. But that doesn't exist.

That should be in the Energy Star data (or APSP or CEC). From my database, the WFE-2 uses about about 1200 watts on high speed and if you had a two speed motor, it would use about 300 watts on low speed.

but wonder what the standard error in the EPA's test procedure is.

The EPA does not test the pumps. The manufactures submit the test data and Energy Star simply enters the data into a database. It is up to the manufactures to either test the pump themselves or have a third party do it. I believe this is the case for all appliances.

And I also wonder why they don't distribute more data throughout the pump curve

The power vs GPM along the head curve is usually fairly linear so you can interpolate between the points or even extrapolate and get fairly accurate estimates.

Anyway there doesn't seem to be the perfect pump out there The Ecostar and the SuperFlo VS seem very efficient in the low-speed environment (perhaps their electronics have the least overhead?) while the Tristar looks to be the best pump for the four-hour hard run. But I can only reach that conclusion because most of the 3450 RPM pumps lack mid-range data.

You need to be careful when comparing VS pumps because again the power draw is proportional to flow rate so you have to interpolate (RPM^3) to get to the same flow rate. Otherwise, you are comparing apples to oranges. One of my spreadsheets (see sig) allow you to do this interpolation on the same plumbing curve (see CompOp).

But, in many cases, what you will find is that a two speed motor replacement will end up saving more over the life of the pump/motor than a VS unless you can get a fat rebate check for the VS.