Waterfall pump vs VS? or other unfiltered feature solution

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djw

Gold Supporter
Apr 17, 2010
216
Colleyville, TX
- When my pool was built long before helpful info was available like tfp, he installed two Hayward NorthStar SS 2hp pumps, one for the pool/spa and one unfiltered pump for the waterfall/slide.

- I suppose there was some redundancy possible in case one pump went down at a bad time, the other could be swapped with minor effort. But I now have a TriStar VS pump on the pool side and the old NorthStar remains on the waterfall.

- The waterfall does not run all the time (freeze cycles and bathers probably two dozen times per year) but the SS Northstar very power hungry.

- The flow out of the NorthStar is about the max mount of flow you'd want for the waterfall/slide and the output can be balanced with valves between those two, or partially closed to add head resistance so the pump doesn't cavitate.

- The 2" pipe run for the circuit is fairly long - maybe 60 feet with probably 8 or so 90's in the run before it makes it to the 3' high waterfall and 5' high slide. The head loss may already put me out of the real waterfall pump operating envelope. Plus, the waterfall pump's separate suction input is a mystery to me - I presume it is pulling from the main drains somehow.

- It would also be good for to have minimal noise, but the sound of the waterfall cascading off a 3' high ledge pretty much drowns out any normal pump noises.

- The proximity of the two does not easily lend itself to plumbing the waterfall into the main return manifold (it's on the opposite side of the filter and the whole circuit is unfiltered), but it could be possible with a few hours of digging and re-routing the two outputs (slide and waterfall), but I would lose control of turning on just those water features from the existing old Hayward 2100 automation controller.

I have been trying to figure out whether I could replace this waterfall pump with a SS pump designed specifically for waterfall use (given the potential head loss), whether a 70 or 120 gpm would be best, OR whether another, possibly less powerful VS pump (for an additional $400 or so) might be smarter so there would always be a "spare" pump on hand under the worst case scenario.

I have not yet upgraded my pool automation system to the level that can directly control VS pumps so I rely on the capability of the pump itself. New automation is maybe next year.

Any experience from anyone with waterfall pumps or other recommendations would be appreciated.
 
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Can't answer you specifically, but here is some info from our setup. We have a Pentair VSF filter pump and a Pentair Whisperflo water feature pump for a pair of waterfalls and a pair of "bubblers" on the sun shelf. I can control and also monitor power usage of these pumps from Pentair's Link2O app (for iOS, Android, or Windows). When my wife and I are sitting outside we like water sounds. We can have that with the water features turned on, or we can have it with the VSF filter pump turned up to higher speed so that water flows over the spillway from the spa into the pool at a higher rate. So, I wondered whether one or the other costs more. Normally, the filter pump would be running at around 1800 rpm. At that speed, it draws 346 watts. At top speed of 3450 rpm, it uses 2506 watts, and dialed back a little, to 2900 rpm uses 1499 watts (I found that 2900 rpm is about the minimum to get sufficient spillway noise.) The Whisperflo pump for the water features uses 2184 watts. So, for water noise, for slightly lower operating cost, I have chosen that the water features are off and the filter pump runs at 2900 rpm. That provides a side benefit of more filtration over using the water features for water noise. Your mileage may vary.

BTW the Pentair IntelliConnect plus Link2O app combination is a pretty convenient way to control these things. I can set schedules with start/stop and speeds for the VSF. Besides the VSF and the Whisperflo, I also have a booster pump for the cleaner on the system, and I was told by Pentair tech support that I can add my Pentair heater if I choose. I can also set the temperature that the system starts up all the pumps for freeze protection and what temperature it turns off freeze protection. Unlike the flakey app I have for my Rainbird sprinkler system, the Pentair system is absolutely reliable, and you don't have to sign out of one phone or PC in order to use another. Only thing lacking is complete documentation, which I'm told is coming, as are more enhancements to the system (which will make the documentation obsolete!)
 
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djw said:
I have been trying to figure out whether I could replace this waterfall pump with a SS pump designed specifically for waterfall use (given the potential head loss), whether a 70 or 120 gpm would be best, OR whether another, possibly less powerful VS pump (for an additional $400 or so) might be smarter so there would always be a "spare" pump on hand under the worst case scenario.
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A waterfall pump is really designed for very low head loss plumbing so it depends on the plumbing setup. Can you describe the waterfall plumbing setup in detail? Pipe sizes, lengths, suction port type (MD or skimmer or port), waterfall height. A picture of the waterfall might help too. Is the current pump very loud when running? It sounds like it is close to run out. What is the model number of the Northstar?

If you go with a smaller pump, the flow rate is likely to be much less and so the waterfall will not look the same.

Also, you have a robot so technically, you really don't need a spare pump. You could run with just the robot and liquid chlorine indefinitely.
 
I think it is 2" pipe all the way to the slide and waterfall. There are Jandy valves on the pressure side (presumably to manage flow and head for the NorthStar). I am guessing 50-70 feet of run with 8-10 90 elbows along the way. Not a short run from pad to features.

I get your point about the robot and bottle chlorine handling a lengthy pump outage, as I just had.
 
djw said:
I think it is 2" pipe all the way to the slide and waterfall. There are Jandy valves on the pressure side (presumably to manage flow and head for the NorthStar). I am guessing 50-70 feet of run with 8-10 90 elbows along the way. Not a short run from pad to features.
Click to expand...
Northstar Pump model#?
Type of suction port?

Likely those are throttling valves for the Northstar so it doesn't go into run out. That probably means that the head loss is going to be low enough for a waterfall pump. However, those pumps are almost as expensive as a low end VS pump.
 
Not a beauty pic. Old pool. No wisecracks :). And it’s not swim season. (Runs for cover).
Click to expand...

No reason for apologies...looks great! I can see myself sipping a cold one under the waterfall.

Unless you run it frequently, you may just want to keep what you have. My feature is also run by an inefficient separate pump. I added a timer with phone-app and Alexa control so we can turn the slide/waterfall on remotely when needed. Just my 2 cents.

Have a great swim season!
 
Perhaps it is the NorthStar SP4020X25 ? That is the up rated 2.5 HP pump.

Also, is the 50-70 feet one way (i.e. distance from pool to pump)?
 

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Ok, so based on that information, the Northstar would be delivering about 113 GPM @ 57' of head. Not close to run out but a significant about of flow. If you use the largest waterfall pump that Pentair makes (AF-180), the flow rate would be around 68 GPM @ 24' of head. So about a 40% reduction in flow rate. That will definitely change the look of the waterfall.
 
mas985 said:
Ok, so based on that information, the Northstar would be delivering about 113 GPM @ 57' of head. Not close to run out but a significant about of flow. If you use the largest waterfall pump that Pentair makes (AF-180), the flow rate would be around 68 GPM @ 24' of head. So about a 40% reduction in flow rate. That will definitely change the look of the waterfall.
Click to expand...

Your calculations reinforced my guess as to the flow reduction using a true waterfall pump. When I looked at the TriStar waterfall pumps I noted that my guess as to head is out of their spec range on the largest model. The NorthStar does put some significant water over the falls.

There really does not seem to be a better solution, given the relatively lower run time of the water feature - a big-ish SS pool pump. Or a VS would have to be running 2K rpm or above for 2/3 the flow rate, consuming 1/4 the electricity. I guess it all depends on run time and min flow for the effect.

When the NorthStar dies (if it ever does), it might be fun to experiment with one of the inexpensive VSP. If anyone has a recommendation in that regard, please share.
 
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I found the label and my old Northstar is a SP4015X20NS.

That motor is interesting and and probably an interesting potential project.

I am wondering how much life I can get out of a 18-year old NorthStar wet end or if there is anything I am missing. I'd want to replace all the inexpensive wear parts. I guess the next step is to tear it down and see.

Are these things sort of like the "farmer's 50-year old axe" (the head has been replaced 3 times and the handle 4 times, "but it is still the same axe")?
 
About the only thing that can go wrong with the housing is a crack but that is usually caused by freezing or something is dropped on it. As for the internals, the impeller is fairly robust and should not need replacement unless it is damaged. The only wear parts are the impeller ring, shaft seal and o-rings which are all pretty cheap. It is a judgement call on to repair or replace. But this is not much more and you get brand new pump:

https://www.amazon.com/Pentair-0110...ds=Intelliflo&qid=1553450237&s=gateway&sr=8-1

This one is the same cost as the motor replacement but it would have about 15% less maximum flow rate:

https://www.amazon.com/Pentair-3420...ds=Intelliflo&qid=1553450237&s=gateway&sr=8-4
 
BowserB said:
Can't answer you specifically, but here is some info from our setup. We have a Pentair VSF filter pump and a Pentair Whisperflo water feature pump for a pair of waterfalls and a pair of "bubblers" on the sun shelf. I can control and also monitor power usage of these pumps from Pentair's Link2O app (for iOS, Android, or Windows). When my wife and I are sitting outside we like water sounds. We can have that with the water features turned on, or we can have it with the VSF filter pump turned up to higher speed so that water flows over the spillway from the spa into the pool at a higher rate. So, I wondered whether one or the other costs more. Normally, the filter pump would be running at around 1800 rpm. At that speed, it draws 346 watts. At top speed of 3450 rpm, it uses 2506 watts, and dialed back a little, to 2900 rpm uses 1499 watts (I found that 2900 rpm is about the minimum to get sufficient spillway noise.) The Whisperflo pump for the water features uses 2184 watts. So, for water noise, for slightly lower operating cost, I have chosen that the water features are off and the filter pump runs at 2900 rpm. That provides a side benefit of more filtration over using the water features for water noise. Your mileage may vary.

BTW the Pentair IntelliConnect plus Link2O app combination is a pretty convenient way to control these things. I can set schedules with start/stop and speeds for the VSF. Besides the VSF and the Whisperflo, I also have a booster pump for the cleaner on the system, and I was told by Pentair tech support that I can add my Pentair heater if I choose. I can also set the temperature that the system starts up all the pumps for freeze protection and what temperature it turns off freeze protection. Unlike the flakey app I have for my Rainbird sprinkler system, the Pentair system is absolutely reliable, and you don't have to sign out of one phone or PC in order to use another. Only thing lacking is complete documentation, which I'm told is coming, as are more enhancements to the system (which will make the documentation obsolete!)
Click to expand...
Where did you buy Pentair IntelliConnect? How much? Do you need any hub to connect to it?
 
djw said:
When the NorthStar dies (if it ever does), it might be fun to experiment with one of the inexpensive VSP. If anyone has a recommendation in that regard, please share.
Click to expand...

The NorthStar finally died. I did luck out and scored a VS EcoStar 2.7 with little run time locally and replaced the NorthStar with it. Given the significant head calculated above (near 60 without choking the valves down), it works will for the situation: high speed has a good flow over the falls, no cavitation, and speeds 1 keeps the slide wet enough for use, speed 2 has lots of water background noise over the falls with not very much energy consumption. In the end a good solution and outcome.
 
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