Intelliflow VF Used As Booster Pump - Energy Challenge

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NickNax

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Aug 4, 2010
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This is my first post on this forum - so please go easy :-D

I have a 20,000 gallon pool with an Intelliflow VF as the main pump, driving a diatomacious earth (DE) filter.

The setup has been working great for over two years. The pool sweep is a Polaris 280, with a separate 2hp booster pump.

Recently, the pool sweep booster pump broke and I self-replaced it with a second Intelliflow VF, reasoning that it would save as much energy as the main pump. Yeah, I know, I should have done my homework BEFORE installing such a fancy pump as a booster, but hey, it's done...

However, the second Intelliflow VF, used purely as the pool sweep booster pump, has been quite a challenge to get just right. I'm hoping some of you experts can provide some good guidance.

Please keep in mind that I have owned a VF for over two years, have read the manual dozens of times, fundamentally understand how the VF works, and love it's flexibility and energy savings.

Here's the challenge:

1. The "booster pump" VF does not prime successfully. I have tried all variations of main pump on/off, main pump high pressure, low pressure, etc. I've fiddled with the "Maximum Priming Flow", high, medium, low, fiddled with the "Water Temperature" parameter, the backwash and vacuum flow rates, in fact, almost every parameter you can imagine, in almost any combination. My conclusion: The narrow feed lines of the Polaris does not allow a flow rate of 30 gallons per minute. (Effectively, too much "head")

To reach the above conclusion, I did the following experiment:

a. Set the "Maximum Priming Flow" parameter to its lowest possible value, i.e. 30 gallons per minute.
b. Partially open (unscrew) the pressure relief valve on the Polaris 280 entry port so that some water "blow by" and therefore flow is increased.
c. The booster VF now easily primes, and in Filter-Run mode, settles at 2200 RPM to reach the programmed target flow of 20 GPM.
d. Some smart people on the forum explained how RPM and flow rate are linear, so I conclude that to reach the PRIMING flow (of 30 GPM) I will need 30/20 * 2200 = 3300 RPM. This is achievable, as the maximum pump RPM is around 3500.
e. When I slowly close the pressure relief valve on the Polaris 280, the RPM count to maintain 20 GPM flow rises to 2900, and you can hear the pump working harder. In this state, I calculate that to reach the required minimum priming flow rate of 30 GPM, the pump would need 30/20 * 2900 = 4350 RPM, which is greater than the maximum pump RPM, so it's no surprise to me that the pump does not achieve prime.

Now, I can actually live with the pressure relief valve partially open (that's how it's set now), the Polaris 280 wheel turn rate is 30 RPM, which is what the manual specifies and it sweeps fine, but the extra flow of water is a waste of energy - the pumps draws about 900 Watt in this mode, but at least, it works.

However, in manual mode, with the blow-by valve closed, and manual speed setting, which overrides any priming requirements, the Polaris runs just fine on about 350 Watt, an almost 60% energy saving, which is why I am still pursuing this - the extra blow-by of water at the relief valve allows the pump to reach prime, but wastes a lot of energy!

The simplest solution I see is to somehow trick the pump to prime at a lower "Maximum Priming Flow" rate, for example 20GPM would work fine. I've tried several times to phone Pentair tech support, asking them if there is even a "backdoor" method to lower the "Maximum Priming Flow" to 20GPM, or even disable priming, but their answer has been "No way", probably since I'm a mere "consumer" (and therefore probably assumed to be an idiot).

Anyways, I'm hoping someone here knows a trick to convince the Intelliflow VF to prime at flow rates less than 30 GPM - or can suggest any other "trick" that would significantly lower the energy usage of the Intelliflow-VF-as-booster-pump application.
 
Welcome to TFP. :wave:

I have one very simple solution that might work; a total guess with no thought behind it. :roll: Background: My pumping station is below my IG pool (part of it is a little higher than the bottom drain, 10 ft deep end, down the hill, under the deck. In this situation there has never ever been any issues with any pump priming. Gravity does it. Of course there have to be extra valves but that is simple.

Anybody think that perhaps putting the "booster pump" into a hole dug down a bit, below the level of pumping station would work? If this would possibly work the main issue I see is making for sure water is able to drain as quickly out of the hole as it enters, even if a small sump pump is needed.


:?: :?: :?:

gg=alice
 
If I understand you correctly the pump does perfectly in Manual mode where there's no mandatory priming flow requirement.

What you have is a programming issue. You can adjust the priming flow but it won't allow you to adjust it any lower than 30gpm. That tells me that it can be adjusted and what you need to know is how to change the limits.

I bet there are registers in the software that holds the max and min limits. I'm not familiar with this drive but all regular variable frequency drives have high and low speed limits and they are adjustable.

You don't need tech support. Not knocking them, but they're going to be useless in this situation. You need to get hold of the engineering dept. I bet someone there (if you can get to the right person) can tell you how to change the limits.

I have no doubt that they can be changed it's going to be a matter of finding the right person. They could have hard coded the limits in there but I don't figure they would, they just restrict the consumer from changing them.
 
I'm reading the VF manual and got to thinking. Yeah, I know that's dangerous.

What happens of you set the priming flow to the min and then set the priming time to 0 mins? I'm sure you've already tried that but I was wondering.
 
If the pump is already primed those settings minimize the auto-prime feature.

If the pump thinks it's not primed (any sort of restricted flow) then it bumps way up on it's own.

I have an annoying clog in my suction line and have played with this priming thing quite a bit. When it pulls real hard I cavitate and suck air from everywhere so loose prime. It's the one annoying part of the pump - there's no good way to tell it to shut up and do what it's told :? Lookin like new pipes in October though :whoot:
 
Bama Rambler said:
I'm reading the VF manual and got to thinking. Yeah, I know that's dangerous.

What happens of you set the priming flow to the min and then set the priming time to 0 mins? I'm sure you've already tried that but I was wondering.
Click to expand...

I think the priming time takes only values from 1 to 15 minutes. I don't think zero is an option.
My VF primes in less than a minute though, it realizes it's primed, and goes back to it's programed flow.

Jeff
 
I went back a reread it and the system prime is the only thing you can set to zero.

So you either need to be able to set the prime time to zero of the prime flow to about 10gpm.

I did a little reading and there appears to be a backdoor into the programming but I can't find out what it is.
 
I would also be interested if you could set the prime to a lower value than the 30 gpm mentioned.

I was guessing that the VF controller would have to be reprogrammed, and also guessing it would have to be done by Pentair. Would be interested to see if that is not the case.

Pentair has a blog where technicians constantly monitor and answer questions, including a pump blog. I'm going to post there, and see what they say.

Jeff
 
The Easy Touch manual lists the range for Max Priming Flow at 15 - 130 gpm via the external controller cable. (As opposed to 30 -160 gpm on the unit itself)

Assuming that's not a typo ....

Ask the Techs about how they test out the unit. It's probably just an RS-485 to RJ-45 adapter and some pc software.

Clearly this is a good way to void the warranty
 

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First on priming, the main pump should push enough water through the second pump that priming is should not be an issue. It is much like a flooded suction so I am surprised there is any issue with priming at all. When you say it doesn't prime, what exactly happens?

Second, A booster pump is made specifically to work with another pump and are designed to work at high pressure low flow rates. They also usually do not have a pump basket so priming is not really an issue. They have large diameter impellers to get the pressure required for the cleaner. The Intelliflo uses a smaller diameter impeller (higher specific speed) to increase efficiency.

Third, you are attempting to use the Intelliflo for something it was not really designed for so it will be difficult to get it to work properly as a booster. Some have had trouble running cleaners off of it when it was used as a main pump let alone a booster. You might be better off trying to sell the second VF and getting a booster or simply skipping the booster all together and try to run the cleaner off of the main pump.
 
Unless I'm all wrong the VF is working wonderfully as a booster pump. The issue is that the VF has a mandatory prime function whenever it starts and that has to be at least 30gpm. Since he can't get 30 gpm through the cleaner he has to open a bypass so the pump will flow 30gpm. Once the priming function is satisfied the pump will function as a booster running at a much lower setting if he closes off the bypass.

The issue is not being able to either 1) set the prime flow low enough or 2) disable the prime function completely. Either one of those things would solve the problem.
 
The issues you are pointing out are exactly why I said the Intelliflo is not really set up to be a booster pump. There are too many overrides that get in way. Besides, it is a very expensive option that doesn't really save that much in energy costs over a properly sized booster pump. Over the life of the pump, you would probably find that a true booster pump is more cost effective.
 
Intelliflow VF - Getting Maximum Prime Flow Under 30 GPM

Thanks for the great responses everyone. You correcctly state that I really don't have a priming problem. The VF is working just fine as a Polaris 280 booster at the moment. My quest (stated in the title) is to lower the energy usage of the booster VF. I've confirmed that option in manual mode already. The root issue is for the VF control program to declare itself properly primed in filter mode even when the flow rate is less than 30GPM. I can even see the issue from the developer's rationale - the pump programmer wanted to make absolutely sure the pump really *is* primed, and what better method to check than a high flow rate to confirm good priming!


Someone knows how to adjust "Maximum Priming Flow" to less than the 30 GPM limit - we just need to get his eyeballs over here!
 
Keep in mind that what you are trying to do is way outside the design goals for the IntelliFlo. Pentair never intended the pump to be used this way. As a result, I would not expect to see any technical support from Pentair for use in this application. It is unlikely that there is anyone outside of Pentair that knows the answers to the questions you are asking.
 
I wonder if someone with a VF and a EasyTouch controller, could actually verify that this Pentair controller actualy has the option to set the VF priming as low at 15gpm, as lightingguy mentioned is written in the manual.

Or perhaps someone with a VF and another Pentair controller, like Intellitouch, or SunTouch could see as well.

All three controller manuals claim that the Priming can be set as low at 15 gpm.
 
Re: Intelliflow VF - Getting Maximum Prime Flow Under 30 GPM

NickNax said:
Thanks for the great responses everyone. You correcctly state that I really don't have a priming problem. The VF is working just fine as a Polaris 280 booster at the moment. My quest (stated in the title) is to lower the energy usage of the booster VF. I've confirmed that option in manual mode already. The root issue is for the VF control program to declare itself properly primed in filter mode even when the flow rate is less than 30GPM. I can even see the issue from the developer's rationale - the pump programmer wanted to make absolutely sure the pump really *is* primed, and what better method to check than a high flow rate to confirm good priming!


Someone knows how to adjust "Maximum Priming Flow" to less than the 30 GPM limit - we just need to get his eyeballs over here!
Click to expand...

NickNax,

A couple of questions. First, you mentioned that when you open up the polaris port for bypass, that the pump will go through the priming sequence just fine but the wattage increases to 900 watts. But did you look at the main pump to see if that wattage actually goes down? The total wattage of both pumps is really what you should be looking at and the total flow rate is what is going to drive the total wattage. So even if the wattage in the booster is going up, my guess is that the wattage in the main pump is going down. Maybe not by the same amount but the total wattage of both pumps may actually not be that much different.

Second, why does the booster pump need to have a priming mode at all? From what I understand this can be shut off. Once the pump is primed manually, it should not need to be primed again unless air is entering the lines somewhere which could then be addressed with other means. So the pump can be set to run at 20 GPM all time in manual mode with no need for priming.
 

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