Insufficent watefall pump size !!! What size should i use

[tillys26]

I have a grotta with a watefall - slide custom built and the water output for the watefall is very insufficent, the pb put a hayward tristar 75/120 gpm watefall pump on it , the watefall is about 6ft high i would say and about 6ft wide. Even with me turing the valve off for the slide so the water only goes to the watefall its still very low, i will try and post some pics tomorrow of the waterfall on. Anybody have any ideas ? or websites, ive been looking all over trying to find someone that knows this information, thanks. Also the pump is about 40ft id say from the waterfall .
Don

 

[mas985]

The Tristar Water fall pumps are offered in two sizes, 75 OR 120 GPM, which do you have? It could simply be undersized for what you need.

They are also low head pumps which means that they will not operate effectively if the plumbing was not designed for high flow. What size pipe do you have?

Looking at the head curve for this pump. it doesn't take much head loss to significantly reduce the flow rate.

 

[tillys26]

Hey Mark thanks for the response , pleasanton huh ,your not that far away from me. Anyways its suppose to be the 120gpm , and i know its either 2 or 2 1/2 inch pipe, i dont think the pb knew exactly what he was doing with the watefall and sizing etc, i remember the guys doing the watefall said i shold have at least a 3hp pump and i think he put a 2hp or less, (the tristar) do you happen to know what size or kind of pump i could look into , obviously the tristar is haywards bigges tfor waterfalls and its abviously not enough and i cant find much info on the google searches so far. Any and all help would be appreciated, thanks
Don

 

[mas985]

I think the biggest problem is that the TriStar is a low head pump. My guess is that the pump is too far from the waterfall and has substantial head loss thereby reducing the flow rate much below 120 GPM. A standard 2 HP should be more than enough HP but it needs to be a standard medium or high head pump. About how far is it from the pump to the waterfall?

I really don't know why they make a low head pump for waterfalls when the water usually has to travel through quite a bit of pipe and be lifted in elevation having significant head loss.

Here is a good list of pumps and they are labeled med or high head. Also on that page are links to pump sizing information.

Also, have a read of the links in my signature to learn a bit more about pumps and sizing.

 

[tillys26]

Thanks for the links mark, im reading up on em right now and trying to figure them out , anyways i went out and measured the pipes and its about 70ft from the pump to the waterfall and then rises up to the top of the watefall 8ft , the line is ran with 2 1/2 " pvc pipe the whole way, and not sure if it matters but the waterfall opening that pours out onto the pool is 6ft wide. Do you sale pumps also ? If so could you give me a recomendation and price, your only about 1 1/2 hrs from where i live maybe i could buy one from ya. Thanks for the input and ill keep reading. Also i forgot to note that the pump splits into two different lines , one for the slide , one for the waterfall , and they DO NOT run thru the filter, its a seperate pump altogether, hope this helps some ?

 

[mas985]

Based upon your information, I would say that the pump your PB put is total insufficient. I don't know what he was thinking. Hopefully you can make a change at his cost and not yours since this is all on him.

It's a good thing you have 2 1/2" piping so you can get some good flow. In order to recommend a pump size, I need some more information:

From your last post, it sounds like the waterfall pump is on it's own loop (i.e. separate suction and return lines from your circulation). What size is the suction side pipe and how long of a run is it to the pool?

Do you want to be able to run the waterfall and slide at the same time?

Do you know what flow rate is required for the slide and waterfall? The slide is usually a minimum and the waterfall is based more upon how much action you want. Otherwise we could just set a fairly high flow rate as a target. The original 120 GPM might be a good target.


BTW, I am a pool owner just like you so unfortunately, I do not sell any pumps. But the good news is that there are a lot of good places to buy them including on the web.

 

[tillys26]

Ha dont get me started,i wish i would have looked into more of this stuff before the pool got built so it was done right with no questions, anyways heres the answers to your questions and im going to put pics on also,
1- YES it is on its own loop, (waterfall-slide)
2-size suction pipe- 2 1/2"
3- the run from the pool is about 25ft i would say
4- yes i want to be able to run the slide and waterfall together, hes suppose to be putting on a valve actuator so you can turn one or both on and ajust the water pressure .
5- flow rate required for the waterfall and slide i have no idea and i know he has no idea, i would think i could always turn it down with the valves, so lets shoot for the most we can get out of it, hopefully the pics come out and you can see how big the waterfall is and you can get an idea how much water needs to come off , i really want it to gush
picture 1 shows in the far left where the equipment is and on the right where the waterfall is
picture 2 shows the front of the waterfall that i am hoping to have a big wall of water come off
picture 3 is a closeup of the way he has the pump and plumbing for the waterfall
http://i240.photobucket.com/albums/ff22 ... 18_1_1.jpg
http://i240.photobucket.com/albums/ff22 ... _2_1-1.jpg
http://i240.photobucket.com/albums/ff22 ... 22_1_1.jpg

 

[tillys26]

 

[mas985]

Ok, given the size of the waterfall, quite nice BTW, you probably don't want it to dribble over the side. So here are a few numbers I came up with based upon the plumbing you gave me. First, let me warn you that these are my best guesses and your results may vary so put that into perspective.

I looked at Northstar pumps but the Super II, Whisperflo and the Max-E-Flo will probably all be about the same. I would go with a high head pump for this setup just to make sure you have a strong enough pump.

So based upon some rough guesses:

120 GPM TriStar ~ 84 GPM @ 19 ft of head (probably close to your current flow rates and relates to about 1.2 GPM/inch of spill over) BTW, can you get a picture with the current pump on and just the waterfall. Just to check the math.

1 HP full rated Northstar ~ 115 GPM @ 34 feet of head
1.5 HP full rated Northstar ~ 129 GPM @ 42 feet of head
2 HP full rated Northstar ~ 143 GPM @ 50 feet of head
3 HP full rated Northstar ~ 165 GPM @ 65 feet of head

2.5" pipe is rated at about 120 GPM but that doesn't necessarily mean that you can't go over that amount just that water hammer could damage the pipes under some extreme conditions. I think you would be safe going up to 2 HP but I probably would not go above that.

Even with a 2 HP, you are only going to get a little over 70% increase in the flow so you have to decide if that is good enough.

Now you might have a problem with the slide in that I would not suggest directing all of the flow to it. This means that you might need to run the waterfall at the same time you are using the slide. The flow rate for the slide only could be too high and might jet well beyond the slide depending on the type of orifice they use. You could still try it but in may end up being too much.

Again, a lot of this is guess work without actually measuring the pressure and suction with your current pump. If you can do that, then we can get a lot closer to actuals.

Another option is to go with a variable speed like the Intelliflo. This will let you control the flow rate to the waterfall and to the slide but it is quite expensive, especially for just water features.

 

[tillys26]

Heres a pic of the watefall without the slide, after looking closer i noticed the slide return line is only 2" (the watefall is a 2 1/2" line ), not sure if or how that will effect the pump action but i do have a valve i can turn the water down on either or if we were to only run the slide. Im waiting on the variable speed pump from hayward so the pb put in two different pumps till the variable pump comes in and he can get it set up. One of them is a max flow 2hp and the other is a super 2 pump but it doesnt have the sticker with the hp rating so im thinking i will have him try replacing the watefall pump with the max flow and see how it works. Would there be anyway i could run the pool filter and the waterfall - slide all off just one pump , the variable speed pump ? Once again i really appreciate you taking the time and helping me out with this.

 

[Guest]

I cant help you other than to say you just need a 3 hp pump for the slide/waterfall and a variable speed pump for the filtering process. But you have an absolutely beautiful pool.

 

[Titanium]

tillys26,

Do you have any way to collect all of the water off of the waterfall for 10 seconds or 30 seconds or 1 minute in order to get an idea of your present water flow? Perhaps you could use a clean plastic garbage can to collect the water?

By the way, I agree with the others. Your pool is very, very nice.

Titanium

 

[mas985]

Tillys26, from what you said, it sounds like you will be replacing the other two pumps, not your waterfall, when you get the variable. What is the other (third) pump for?

Also, I had another thought. You may be able to run your current waterfall pump as a booster instead of a separate pump. This is probably what Hayward had in mind for that pump and not for it to be on a isolated loop. So to do this, your PB would need to plumb the suction side of the pump somewhere after the filter but before the SWG. However, this does mean that you would need to have both pumps on when running the waterfall. Other advantages of this setup are that the current waterfall pump gets a boost from the circulation pump and would probably provide close to the 120 GPM maximum, you have filtered water going down the slide and waterfall and you will be able to control the flow rates of everything with the variable speed pump. So you will be able to adjust how much water is coming out of the waterfall and slide independent of which is on. Just another way to approach the problem without the cost of a new pump.

 

[tillys26]

Thanks mark vince and titanium, im pretty happy with the way the pool looks i just wanna get it running right. As for collecting the water coming off the waterfall it would be pretty difficult, the waterfall is in the deep end and way to wide for me to collect all the water coming off of it. Right now mark he has three pumps , one is the waterfall, one is the filter and shallow end skimmer, and the other is running the deep end skimmer, those last two will be reduced to 1 when i get the variable speed pump. I will run the last scenario by him when he comes back out , but i dont know how he would be able to tie the waterfall pump into the plumbing of the filter since the swg connects right out of the filter, but its worth a shot and ill ask him. Vince you said just go with a 3 hp pump, but wouldnt that be putting to much water thru my 2 1/2 inch pipes and then id be just wasting the extra hp ?

 

[mas985]

From the photos it looks like you have plenty of room to put in a tee and branch out to the waterfall pump. Should be easy to do and not take very long. The horizontal section right after the filter should work well.

Also, if I would not put a 3 HP pump on 2 1/2" plumbing although I'm sure it has been done. Just not an efficient way to go.

 

[tillys26]

Perfect Mark, im gonna show tell him and see what he says, prob wont be able to do it for a few weeks til the new pump comes in but i will let ya know and post some pics so we can compare them after its installed like you said, hopefully this will work Now if i wanted to just run the waterslide and or the waterfall both pumps would be on correct ? Guess its not a big deal cuz its not like they are always on and its probably gonna be alot better for the slide to because i want alot more water coming down the slide thanks againg, gosh i love this website

 

[Titanium]

tillys26,

I notice on reexamination of your photos that your concrete equipment pad is pretty crowded right now, although I guess you will have more room after your three pumps go down to two pumps. It does not look like you will have any room if you decide to later add a natural gas heater for the spa or a heat pump for the pool.

Also, what is in the white electrical box? Is it just an electrical panel with circuit breakers, or does it also have some kind of control system inside? The geek engineer in me loves knowing these kind of details.

Also, I see from your posts that your pool was started on October 20, so it has been over a month. Is your PB planning on painting the white PVC plumbing? The ultraviolet (UV) from the sun willl eventually cause the PVC to degrade.

Also, has your PB done any kind of flow or hydraulic calculations? If so, can you get him to share the calculations with you (and us)? If not, tell him that the gang at TFP thinks he should get a super wedgie. And if he hasn't done any calculations, maybe he will get sufficiently embarrassed that you, as the customer, had to go get calculations from the Internet.

Titanium

 

[mas985]

After thinking about this some more, having more than 120 GPM through your filter may not be such a great idea. Because of the high flow rate requirements, you really are better off with a separate plumbing loop. So I take back my previous idea.

You said that you had a 2 HP MaxFlow which might be big enough for your needs. When you get the VS pump, move the 2 HP over to the waterfall and you should definitely get more flow. If it is still not enough, then you may have to look at other options.

 

[tillys26]

titanium, your right the pads not as big as i thought it should be but once we get rid of the one pump it should be better, only thing is that that filter is a 30"filter and i paid for the 36" so im waiting for him to make good on that, , also the control panel behind holds some breakers and the remote control system for turning the pool,lights etc on. As for the calcs for the plumming i highly doubt it, hes come up with alot of hmms and i dont knows so i really doubt he did the right calcs if any obviously due to the results of my waterfall flows and as for the heater and or spa im not going to to with either, im in california and were on a hill, the pool gets full sun all day and im hoping that i dont end up having to hot of a pool, i would like to eventually run solar maybe to get a few more months out of the pool but electrical and gas prices are crazy out here so im trying to keep away from any more bills then i have to with the gas heaters etc.

 

[crabboy]

Not sure if this has been suggested yet, but why not have a valve that can divert all the filter water to the waterfall or the returns and just allocate the waterfall/slide pump to the slide only?

As for calculating the flow, instead of capturing the water as it falls off the waterfall, can you capture the water at the waterfall return, maybe a small section of hose or pipe?

I've got a 2hp for my slide and it gives way more water than our slide needs.