Intelliflow VF Used As Booster Pump - Energy Challenge

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mas985, he is using an IntelliFlo VF as a booster pump. The IntelliFlo VF goes through a "priming" mode every time it turns on or the flow rate is changed. There is no way to skip or disable the priming mode when using a flow based setting. Priming mode is not used when using a speed based setting.

NickNax, what happens when you set a speed, instead of a flow rate? You should be able to get the pump to tell you what flow rate it is running at while in speed mode and then adjust the speed to get the flow rate you want. If you can get it to work in a speed based mode, you shouldn't have a priming problem.
 
I understood the OP was using the second pump as a booster but I thought there was an external controller that could be uses to control the pump in manual mode.

Also, one thing does not make sense to me. If all of the flow is directed through the cleaner @ 20 GPM, the RPM goes to 2900. Based upon the Intelliflo head and watt curves, @ 20 GPM and 2900 RPM the head would be about 67' and the wattage whould be about 1000 watts which are very extreme operating conditions. But based upon Pentair documentation 20 GPM @ 2900 RPM and 350 watts is not possible so something does not add up.

A few more questions:

Exactly how is the booster pump plumbed into the system? Suction tap location, suction and return pipe size, length to the pool.

What was the normal filter pressure set to in the booster settings? This should NOT be set to the actual filter pressure but to the pressure the cleaner requires and/or the pressure measured at the pressure side drain plug.

What is the operating point of the main pump (RPM/GPM/Watts) and the filter pressure with and without the booster running at 20 GPM.

What happens to the booster RPM/watts when the main pump flow rate is increased (both should decrease)?
 
JasonLion said:
NickNax, what happens when you set a speed, instead of a flow rate? You should be able to get the pump to tell you what flow rate it is running at while in speed mode and then adjust the speed to get the flow rate you want. If you can get it to work in a speed based mode, you shouldn't have a priming problem.
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Jason, the VF runs in a speed based RPM mode, only in Manual. And even then, if you tell it to run at a certain RPM in speed mode in manual, it does not show the flow in gpm.

(I know it's weird, in Manual mode you can tell it to run at a certain gpm, and it will also show RPM. But, still in manual, you can input a speed in RPM, and no gpm is shown.)

Jeff
 
JasonLion said:
Right, you can only set a speed in manual mode. The question is, does it work when you do that? Can you turn the pump on and off and not get priming errors?
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You can set a speed or flow rate in manual mode. When you select a flow rate in Manual mode, the VF needs to go through Priming sequence. However, when you select a speed in Manual mode, the VF goes immediately to that speed, and skips the Priming sequence.

And it works. As NickNax pointed out:
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!
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mas958,

The main pump draws slightly less power (around 110w less) when the booster is on. That is a lot less energy than what the booster pump is wasting. I've confirmed by (manual mode) experiment that the key reason for this is the extra 15-20 GPM of flow needed to ensure "priming" of the booster VF. The excessive flow is simply blown out the Polaris' pressure relief valve. It works, but wastes a lot of energy.

The control program in the Intelliflow VF requires a minimum of 30 GPM flow. If the pump cannot achieve 30 GPM of flow by the time the pump hits maximum RPM, the control program simply declare a "Priming Error" and shut the pump down until you manually reset it. It will declare this error even when the pump in practice is fully primed. So, one has to distinguish between the case of the pump not having water in (not my case) and the case where the control program declares that the pump did not prime (my case).

What I'm actually asking is, "Can the VF somehow be coerced to accept a priming flow lower than 30 GPM". You are of course correct that in manual mode, the VF can be made to run at any speed (that is in fact how I verified that significant energy savings can be had) but all the automatic (timer) modes start with the "Priming Check" step, which throws an error and irritates the heck out of the neighbors because the pump keeps cycling up and down.
 
I am still concerned about the high RPMs required for only 20 GPM. Richard, aka chem geek, has posted these numbers for his cleaner (ThePoolCleaner) on the Intelliflo:

15 GPM, 1370 RPM, 200 W, 4 PSI, 13.0%
18 GPM, 1475 RPM, 245 W, 4.5 PSI, 14.4%
21 GPM, 1610 RPM, 300 W, 6.5 PSI, 19.8%
24 GPM, 1850 RPM, 420 W, 8 PSI, 19.9%
Click to expand...

As you can see they are much lower RPM than the numbers you are seeing which to me would indicate a problem with your setup somewhere. I don't think your cleaner operates at that much more PSI than Richard's. If there is an issue in either the cleaner line or the booster suction then fixing this problem would allow the pump to go through the prime cycle since it wouldn't ever reach the peak RPM.

Have you checked the cleaner lines to make sure there is nothing stuck in them?

The numbers that you posted 20 GPM/2900 RPM, what was the main pump GPM & RPM settings?

Also, what was the filter pressure with and without the booster running?
 
mas985 said:
I don't think your cleaner operates at that much more PSI than Richard's. If there is an issue in either the cleaner line or the booster suction then fixing this problem would allow the pump to go through the prime cycle since it wouldn't ever reach the peak RPM.
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The Pool Cleaner is designed to operate under low flow AND low pressure conditions since its designed to work without a booster pump, but I don't think that's the case for the Polaris 280 which probably expects much higher pressures at low flow rates (i.e. it is much more restrictive to flow than The Pool Cleaner). That's why a booster pump is required for the Polaris 280. This is similar to the situation I used to have with my Letro Legend before I got the IntelliFlo.

Also note that the part you quoted was for the dedicated line without The Pool Cleaner attached. With The Pool Cleaner attached, I get the following:

chem geek said:
15 GPM, 1955 RPM, 425 W, 10.5 PSI, 16.1%
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I have my Pool Cleaner on my main IntelliFlo VF with a valve to a dedicated line to the cleaner and I have the flow rate set to 15 GPM, but that's done through an IntelliTouch controller. The pump is already primed and is just switching flow rates when the valve is switched to the cleaner. I am surprised that the booster pump is 2 HP since most are around 3/4 HP including the ones sold by Polaris.
 
My booster pump VF numbers are:

15 GPM, 2380 RPM, 650 Watt

This is in manual mode, with "constant flow rate" of 15 GPM selected. The Polaris 280 safety valve is opened for significant blow-by so the pump can achieve 30 GPM flow at start up. As pointed out previously, the 30 GPM flow is required by the pump control algorithm before the pump will declare itself primed. I have also checked the Polaris 280 feedlines for blockages - there are none.

So again, if anyone figures out how to "cheat" the priming control algorithm of the VF to accept a priming flow rate lower than 30 GPM, I will be most thankful.
 

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Richard,

Thanks for correcting me on those numbers but I still think that an operating point of 2900 RPM for 20 GPM (bypass closed) seems a little high and would indicate extreme pressure in the cleaner. I know ThePoolCleaner can operate at lower pressures and flow rates but I didn't think the Polaris operated at 2-3x higher pressure. Unfortunately, it is difficult to find any data on the required operating point for the Polaris since they probably assume a standard booster will be used.


NickNax,

I understand you really want to be able to lower the minimum prime flow rate but I suspect that is hard coded in the firmware and the only way to change it would be to get some custom code and reflash the controller. I doubt Pentair would go through the trouble for you but you could ask.

However, there may be other ways to get around the issue if you are interested. I posted several questions several times that would help me to better understand the operating conditions and perhaps would point to another solution. So if you are interested in another solution, please answer the follow questions:

What is the MAIN pump setting when you are trying to prime the booster (GPM, RPM, Watts)? What other settings have you tried?

Also, what is the filter pressure during the priming process and how does it change?

Increasing the Main pump GPM/RPM will have the effect of increasing the pressure on the booster suction side and reducing the booster RPMs required for the priming cycle. So again, if you are interested in another solution, try running the main pump at a much higher RPM such that the filter pressure is between 20-28 PSI and see if the booster completes the priming cycle. If it does, then there may be a way to work out the programming sequence to get this to work.

[EDIT] Just confirmed with Polaris tech support that the cleaner needs around 12 GPM @ 30 PSI to get to 30 RPM wheel revolution. So even if you set the Intelliflo at 15 GPM, you may need to have a least some bypass.
 
mas985 - Thanks for the suggestion, but I already tried the hypothesis of assisting the booster by manually forcing the main pump run at maximum flow (3450 RPM) - it did not work.

In filter mode, the main pump runs at 40 GPM, 2325 RPM and 800 Watt. This drops ~110W with the booster running. The filter pressure is 9 PSI which drops to 7 PSI with the booster pump on.
 
Richard has the best news so far. Being able to set the priming flow to 15 gpm with the IntelliTouch says that the low limit can be lowered.

NickNax -- Did you contact the guy that has made the custom controller? he may have your answer.
 
NickNax said:
mas985 - Thanks for the suggestion, but I already tried the hypothesis of assisting the booster by manually forcing the main pump run at maximum flow (3450 RPM) - it did not work.

In filter mode, the main pump runs at 40 GPM, 2325 RPM and 800 Watt. This drops ~110W with the booster running. The filter pressure is 9 PSI which drops to 7 PSI with the booster pump on.
Click to expand...

After my last post, I found out from Polaris that the operating point requires much higher PSI (30) that I originally thought was necessary and at very low GPM (12). Basically the equivalent of a 1/2" pipe 21' long. Assuming their numbers are correct, this would mean that 177 PSI of pressure would be required to move 30 GPM of water. Each pump can produce at most about 39 PSI each @ 30 GPM for a total of 78 PSI maximum so you would need close to 5 pumps in series to get that much PSI. But even at 15 GPM, both pumps would need to produce about 47 PSI total but still possible as you found out from your tests.

You probably don't want to hear this but if energy efficiency is your real goal, IMHO I still think you would be better off selling the second Intelliflo and also the Polaris plus buying either ThePoolCleaner like Richard has or a robotic. Both would probably save more energy than your current setup and even with selling the second Intelliflo at a loss, you will probably come out ahead $$ wise over time.
 
@ride525

I basically have two solutions:

1. Open the "blow-by" valve on the Polaris 280 entry port until enough extra flow allows the pump algorithm to declare itself primed. This is the current solution, but the extra "blow-by" water under fairly high pressure waste 400-500 Watts while the booster is running. Running about four hours/day, that cost me around $60 per year.

2. Buy & install an Intellitouch controller, which will allow me to set the "Max Prime Flow" parameter down to 15 GPM. They go for around $420, which is equal to seven years of energy waste cost.

Based on the above, I've decided for the moment to stick with #1 and suck up my irritation at the needless waste of energy.

For the life of me, I can't understand why a remote can program the prime flow lower than the built-in keyboard, but Pentair tech support is an absolute stone wall to non-installer customers. I'll keep on hoping a backdoor method to lower the priming flow limit will become known.
 
More than one year later:

I've now optimized the amount of blow-by on the Polaris cleaner entry port so that "just enough" unneeded flow occurs to convince the Intelliflow VF that priming was successful.

With this optimization, the "wasted" flow causes only around 300W of extra power, instead of the 400-500 W I measured before optimization.
In addition, the Polaris cleaner now runs only 3 hours per day instead of 4, and still does a good job.
With the above saving, the break-even period between purchasing an Intellitouch controller and just eating the cost of the wasted power is around 12 years.

The initial decision to just eat the $30 of extra electricity per year (instead of buying a $360 controller) turned out to be sensible.

Of course, if anyone ever figures out how to adjust/tweak/hack the minimum constraint of the Intelliflow VF "Maximum Prime Flow" parameter to below 30 GPM (without using an external controller) I would still be deliriously happy to hear about it.
 
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