Waterfall suggestion: 75 or 120 GPM? (video)

[socrates]

I'm contemplating replacing the pump on a waterfall in an effort to save money on electricity. The current pump dedicated to the waterfall is a Hayward SP4015NS attached to a 1.5 HP Northstar motor. The pump I'm contemplating replacing it with is a Hayward TriStar waterfall pump. Hayward makes two models of this pump, one which typically generates ~75GPM and a second which generates 120GPM. I am trying to decide which pump would be most appropriate. Can someone with experience help?

Here is a brief video of my current waterfall in action. The waterfall is perhaps 6 feet high and 9 feet wide. Ignore the hose at the top of the waterfall: that was a neighborhood kid screwing around. The waterfall pump is at my equipment pad, which is located perhaps 10 or 15 feet behind the waterfall: http://youtu.be/KGNnsHbd3P0

I don't mind a more impressive waterfall if the water flow doesn't destroy it.

Here is the brochure with curves for the Hayward TriStar pumps. I believe these pumps can be plumbed to fit my current setup: http://www.ezpoolz.com/content/tristarwaterfall.pdf

Despite a lot of searching, it isn't clear to me what the HP of these TriStar pumps are, and how much energy savings I might realize from installing one.

Based on the video, can anyone suggest an appropriate GPM/rate of flow for my waterfall? Any thoughts on what energy savings I might (or might not) realize? Thanks.

 

[mas985]

Re: Waterfall suggestion: 75 or 120 GPH? (video)

First, both pumps are rated in GPM not GPH. Big difference.

Second, when you move more water, the pump uses more energy. So the 75 GPM pump would cost much less to run but it may not give you the proper look.

Third, the Norstar was probably producing closer to 120 GPM than 75 GPM so the larger pump will probably give you a similar look.

Fourth, those pumps may or may not work on your setup. They are very low head pumps so the plumbing in the waterfall has to be short and large diameter.

Can you describe the plumbing in more detail? Pipe size, number of bends, the type of suction port and the return connection to the waterfall.

 

[socrates]

Re: Waterfall suggestion: 75 or 120 GPH? (video)

Thanks, mas985. I noticed my GPH error and fixed it around the time you were posting your reply

We bought the house with the pool already installed, and no information was forthcoming from the sellers, so I have to go by observation. Please look at the last two photos on this message thread: 6-foot-waterfall-is-there-a-pump-that-won-t-bankrupt-me-t41172.html. As indicated in the caption, the waterfall pump and plumbing is on the far right of the equipment pad.

Just measured: the pump is about 23 feet from the waterfall.

The pipes are labeled 2".

What other information do you need/what should I be looking for or taking more pix of?

If a waterfall pump is inappropriate based on my setup, are there other energy-efficient ways I could install a suitable pump? Say, something that was near the waterfall itself? There is electricity running all over the yard. I would want something reliable and safe.

 

[mas985]

Re: Waterfall suggestion: 75 or 120 GPH? (video)

Waterfall pumps are very sensitive to head loss so I need to get the right head loss to give you good advice. With a 23' run and 2" pipe, I would not be confident in using a waterfall pump unless you are willing to measure the head loss. This requires both a pressure and vacuum gauge on your current pump. With a head loss measurement, I can then determine the flow rate of your current pump as well as the flow rate of any other pump you might decide to use. I can estimate the head loss, but it is just an estimate and I would feel much better if you could measure it. For the estimate, I need the following:

Where does the pump draw water from? (e.g. it's own dual/single main drain)

What does the exit of the 2" return pipe into the waterfall look like?

Can you estimate the number of 90s in the pipe suction and return?

Having the pump near the waterfall would probably help and may allow you to use a waterfall pump which would be a little more efficient but the cost to move the pump and a new pump might end up being more than the energy saved.

 

[socrates]

Re: Waterfall suggestion: 75 or 120 GPH? (video)

Getting answers beyond guesses for your questions may be difficult. Is there a way to install a pressure and vacuum gauge on my existing Hayward SP4015NS pump? As I understand things that would give us an authoritative answer.

One thing I may be in the process of figuring out here is an eventual strong case for photovoltaic solar on my house: a lot of my energy conservation concerns would evaporate. The summer sun blazes here in Sacramento, California.

 

[carlscan26]

Re: Waterfall suggestion: 75 or 120 GPH? (video)

Socrates, can you add your pool specs to your signature? You configure it in the user control panel up at the top of the page.

How big is your pool that you have a dual filtration system and two cleaners?

 

[mas985]

Yes, measuring pressure and suction on a Northstar is very easy. The drain plugs on most pumps is a 1/4" thread which a standard pressure gauge will thread into. On the suction side, the drain plug is also 1/4" so a typical auto suction gauge should work fine although you may need to get a 1/4" thread adapter for hose.

Having an extra pressure and suction gauge is good to have anyway for troubleshooting and they don't cost all that much.

 

[socrates]

thanks mas985, I will order both from amazon. where would I find these drain plugs for the pump and for the suction side? How can I figure out if I will need a 1/4 thread adapter on the suction side? Will I need to throw a circuit breaker before doing installation?

 

[mas985]

The drain plug for the suction side is at the bottom of the pump basket.

If your suction gauge has a 1/4" thread already, you do not need an adapter. If it has a hose attached, you probably will. There are quite a few on ebay which have the 1/4" already.

Not unless the pump can turn on accidentally.

 

[socrates]

The drain plug for the suction side is at the bottom of the pump basket.If your suction gauge has a 1/4" thread already, you do not need an adapter. If it has a hose attached, you probably will. There are quite a few on ebay which have the 1/4" already

Thanks. I see two plugs on my pump that might accommodate a 1/4" gauge. I don't see any other obvious ports on the other piping. Are these the two areas that need gauges? (photos attached.)

 

[socrates]

one more pic of piping that is in front of my waterfall pump. Not sure what the three pipes at top are for -- perhaps a planned solar installation? There are pipes for solar pool heating on the west side of the house, but no solar system was built.

 

[mas985]

Yes those are the drain plugs.

And the other valve might be solar but it is hard to tell. If you turn the valve SLOWLY does the pressure start to rise in the filter? Don't turn it all the ways as it might completely block the line.

 

[socrates]

so those are the two plugs that I need to hook the gauges to, is that correct? thanks for the help.

 

[socrates]

gauges ordered Re: Waterfall suggestion: 75 or 120 GPM? (vid

OK, I have ordered vacuum and pressure gauges with 1/4" fittings. Will revisit this thread in a few days when they arrive. Thanks again.

 

[socrates]

have guages, now what? Re: Waterfall suggestion: 75 or 120 G

I have received both a pressure gauge and a vacuum gauge. Mark, can you suggest where I should screw each of these gauges in to take the measurements?

 

[mas985]

Remove the pump drain plugs and the gauges should screw right in.

 

[socrates]

Thanks. As stupid as it sounds, I don't know for sure which drain hole will allow me to measure vacuum/suction, and which measures pressure. I don't want to wreck my new gauges. Which gauge goes on which end of the pump? (You can describe it in terms of "nearer the motor" and "nearer the pump end.") Can you help?

 

[mas985]

The drian plug at the bottom of the pump basket is the suction side of the pump so the vacuum gauge goes on that one. The other is for the pressure gauge.

 

[socrates]

numbers! Re: Waterfall suggestion: 75 or 120 GPM? (video)

OK, here are the numbers:

There is a valve at the head of the waterfall pump, as shown in some of the pictures above. I found that changing the position of that valve affected the PSI a great deal, and the vacuum level slightly. I think that adjusting the valve may have affected the flow of the waterfall, but I didn't play with it long enough to be certain.

The vacuum side has a fairly constant 20-22 vacuum.

The pressure side measured from 10 - 20-ish depending on where I set the valve.

The pump and motor type is now listed in my signature.

No idea what to make of those numbers.

 

[mas985]

Here is your current pump's operating point:

115 GPM @ 47' of head & 2200 watts

With that much head loss, you won't be able to use a waterfall pump. The two pumps that you chose have a max head of less than 30'. If you tried to use the larger of the two pumps, the flow rate would be half of what it is now. Even if you shortened the distance, I am not sure it would matter much. It depends on how many fittings you can eliminate. I think the reason they went with the pump you have now is because it is necessary. The Northstar is a powerful pump but it is also fairly efficient. Even if you used an Intelliflo running at 3000 RPM to get the same flow rate, it would use only about 10% less energy.

BTW, do you normally operate the waterfall with the valve completely open (10 PSI)? If not, then you could reduce the impeller size and get a little more efficiency but you would have less flow rate.