pentair intelliflo effeciancy

[Suley]

Re: pentair intelliflo effeciancy New numbers and a surprise

Hi again,

Wont know too much about the plumbing as i just brought the house but do know that there must be two suction runs. One from the pool and the other from the spa. Should we count the skimmer as another suction run?

Pipe diameter is 2" SCH 40 PVC.

Will get back to you with the reading at 2600rpm and the actual distances from the pump to the pool.

I got some fresh numbers on the Watts and got a surprise when i plugged them into Watts2GPM.

I calculated the pump run time for 1 water change and calculated my electricity cost to see how much it will cost for running the pump at 1 water change per day for 30 days. Here are the numbers:

850 rpm - 10.38GPM - 37.88 Hours per day - $14.68 per month (not a possible scenario)
900 rpm - 14.12GPM - 27.86 Hours per day - $11.68 per month (not a possible scenario)
1000 rpm - 16.08GPM - 24.46 Hours per day - $11.61 per month (not a possible scenario)
1100 rpm - 16.32GPM - 24.10 Hours per day - $12.87 per month (not a possible scenario)
1200 rpm - 18.76GPM - 20.97 Hours per day - $12.94 per month
1300 rpm - 22.86GPM - 17.21 Hours per day - $12.53 per month
1400 rpm - 29.22GPM - 13.46 Hours per day - $11.82 per month
1500 rpm - 34.66GPM - 11.34 Hours per day - $11.89 per month
1600 rpm - 38.16GPM - 10.31 Hours per day - $12.64 per month
1700 rpm - 39.90GPM - 9.86 Hours per day - $13.88 per month
3450 rpm - 83.56GPM - 4.71 Hours per day - $46.50 per month

I am surprised to find that i will be spending least amount in electricity at 1400-1500 rpm range!

Do you think i am on the right track? Is this accurate?

Thanks!

 

[mas985]

Do you have the wattage & filter PSI for each of those RPMs? That is all I really need.

Also, are there only two suction pipes (spa and pool) that come to the pad? They will usually connect via a valve right before the pump.

Do you have any check valves in the plumbing?

Post a picture of your pad equipment if you don't the answer to the above questions.

 

[Suley]

Hmmm... dont have the filter PSI on me... didnt get them as we determined that they are inaccurate on low rpms anyway... however i will get them to you by tonight or something...

There are individual lines coming out of the ground going to the pool and the spa pump. At the pool pump there are 1 each 3 way valves on the suction side and the return side where the piping goes into and comes out of the ground. both these valves have marked pool and spa sides.

I dont see any check valves and i dont think i have any as when i clean the pump strainer, water drains back like anything and i have to fill the pump cavity with water before startup.

I will take a picture and post that too.

 

[Suley]

Hi Mark,

Here are the readings:

2600 rpm - 1102 Watts - 14.25PSI at filter guage. Wattage fluctuated between 1102 to 1115 but was steady at 1102 most of the time.

Pool to pad distances:

Main drain to pump - 33 feet plus about 3 feet to the actual drain
Spa drain to pump - 57' 6"
Skimmer - 39' 6"
Pool is 35' X 15' - 3.5' at shallow end - 8.5' at deep end (add 0.5' to pool top to all depths)

Now for the readings I was talking about which made 1400-1500 rpm look good:


1000 rpm - 1 psi - 120 watts
1100 rpm - 2 psi - 132 watts
1200 rpm - 2.5 psi - 155 watts
1300 rpm - 3 psi - 184 watts
1400 rpm - 3.5 psi - 222 watts
1500 rpm - 4.0 psi - 264 watts
1600 rpm - 4.9 psi - 311 watts
1700 rpm - 5.5 psi - 356 watts
1800 rpm - 6.25 psi - 410 watts
1900 rpm - 7.0 psi - 476 watts
2000 rpm - 8.0 psi - 545 watts
2100 rpm - 9.0 psi - 617 watts
2200 rpm - 10.0 psi - 701 watts
2300 rpm - 11.0 psi - 793 watts
2400 rpm - 12.0 psi - 890 watts
2500 rpm - 13.0 psi - 1010 watts
2600 rpm - 14.25 psi - 1102 watts

At speeds lower than 1000 rpm it was too difficult to read the pressure guage. But please let me know if they areimportant and i will try my best.

Also the picture of the pump setup is attached. As far as I know there is no check valve. water drains back like crazy when i open the pump strainer for cleaning and i fill the pump with water before restarting it.
[attachment=1:2547smwa]photo2e.jpg[/attachment:2547smwa]
[attachment=0:2547smwa]photoe.jpg[/attachment:2547smwa]

 

[mas985]

I don't see a check valve either which means you should be able to use a constant plumbing curve for all RPMs.

So here is a slightly modified spreadsheet which uses the first data point (2600 RPM) as a calibration point to get a plumbing curve for all other RPM values. I used both Watts2GPM and PSI2GPM as separate calculations to see how well they track each other when calculating GPM and Watts. The two sheets use slightly different methods to get to the same results so you can compare the results to see how close they come to their respective estimates.

Both sheets seem to be calculating similar plumbing curves at 2600 RPM which is encouraging. Plus both the PSI and wattage seems to be close to the values that you measured for other RPMs. The error in the wattage calculation vs what is measure is fairly small until about 1400 RPM where it starts to grow and what I expect. Part of the problem at low RPMs could be due to the CEC measurement data error. It doesn't take much error to throw things off when doing these types of calculations. But since I am using the published head curve for the Intelliflo, the GPM values should be fairly accurate across all RPM values.

800 RPM seems to be the most efficient point for your plumbing curve which results in 19 GPM at 100 watts but that may not yeld enough flow rate for your skimmer so you may want to up that some.

 

[Suley]

Thanks Mark!

One thing I noticed was that intelliflo VF was selected in the drop down box. I changed it to Intelliflo Variable speed and there was no change in the numbers. So I should assume that the calculations are still accurate?

What a difference from the older calculations!

I think i will set it to 900 rpm for 21 hours a day and if the skimmer acts up, I will get one of those arms which attaches to the skimmer to stop debris from passing by...

Or i can program the pump to run at a slightly higher speed at certain parts of day sacrificing efficiency for skimming action.

Oh, you were able to infer the scenario at lower rpms even though I did not have the readings?

Most of all, Thanks!

 

[mas985]

All the Intelliflos have the same performance so that doesn't really matter.

All RPMs below 2600 are calculated from the 2600 calibrated values and not from your measurements that is why any RPM can be determined.

 

[Suley]

Thanks so much Mark!

This has really solved my dilemma of determining the best pump speed and run times!

Thank you!

 

[Suley]

One more question...

In the future, if i change the valve position, will your last sheet still be valid if i plug in the numbers for 2600 rpm?

Thanks!

 

[mas985]

If you change any valves, the power draw reported by the pump should change if there is a change in head loss. You can enter that new value under 2600 RPM and then all the other RPM's will be recalculated. But things should not change all that much.

 

[Suley]

Thanks Mark!

You rock!

Here is a treat for you... and I am only on the first B of BBB!

[attachment=0:3mq779wx]ool.jpg[/attachment:3mq779wx]

 

[mas985]

Looks nice!

 

[shakenbake]

I have quite a bit of head (plumbing complexity and pump is about 3 feet above pool surface)

Note: this is read from a flow meter before the filter (don't ask me why the PB did this, I'm cleaning the darn thing constantly)

DE Filter was relatively clean: