Disappointed with Intelliflo VSF gpm at low rpms

senex

Gold Supporter
Mar 20, 2018
10
Austin, TX
#1
I got an Intelliflo VSF installed yesterday (I haven't updated my signature line because I forgot to write down the model number this morning).

The pump has a digital readout of RPM, Watts, GPM, and PSI. I recorded some values this morning:

[TABLE="class: grid, width: 500"]
[TR]
[TD]RPM[/TD]
[TD]Watts[/TD]
[TD]GPM[/TD]
[TD]PSI[/TD]
[TD]PSI on DE Filter Gauge[/TD]
[/TR]
[TR]
[TD]1000[/TD]
[TD]62[/TD]
[TD]7[/TD]
[TD]3[/TD]
[TD]6[/TD]
[/TR]
[TR]
[TD]1600[/TD]
[TD]190[/TD]
[TD]12[/TD]
[TD]8[/TD]
[TD]12[/TD]
[/TR]
[TR]
[TD]2000[/TD]
[TD]364[/TD]
[TD]18[/TD]
[TD]13[/TD]
[TD]17[/TD]
[/TR]
[TR]
[TD]2600[/TD]
[TD]871[/TD]
[TD]32[/TD]
[TD]22[/TD]
[TD]25[/TD]
[/TR]
[TR]
[TD]3000[/TD]
[TD]1340[/TD]
[TD]41[/TD]
[TD]29[/TD]
[TD]31[/TD]
[/TR]
[/TABLE]

Those are the values reported on the pump's lcd screen when I manually change the rpm (except the last column, which is the DE filter's gauge).

I am disappointed. I bought the VSP based on many users reporting positive outcomes running at whisper-quiet 1000rpm. For me, 1000rpm will take 35 hours to turn over a small pool, and will give no flow at all through the hottub (the hottub has a spillway into the pool, and thus requires more pressure to push water up and over the spillway).

To get any reasonable flow requires around 2500rpm, which is nearly as loud (perhaps louder) than my old Jandy 2HP pump. And the power savings are smaller than I expected, due to the high RPM required.

I'm guessing that my pump's digital readout is accurate and that my plumbing must have "high head," but I don't understand the practical steps of how to find the biggest problems and fix them. Pipes appear to be 2". I have pretty standard equipment, perhaps more right angles than strictly necessary. All equipment is at an elevation about 4 feet below water line.

What is the best way to diagnose the problem? Are there solutions that don't involve massive replumbling of the whole setup?

Thank you -
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
41,197
Tucson, AZ
#2
Turn over is meaningless. There is no need to target a specific amount of water moved.

Those flow rates do seem very low and must mean that you have a VERY high headloss system ... or the flow rate read out is just wrong. We typically do not recommend the F model as there is no real reason to need to know the flow rate.

What specific filter do you have? assuming the pressures you are listing are from the filter, they seem higher than I would expect unless the filter is way too small or it is dirty or the grids are scaled up with calcium.

One test you could do is remove the grids and run it without and see what flow rates and pressures are then reported.
 

senex

Gold Supporter
Mar 20, 2018
10
Austin, TX
#3
Thanks for your reply!

I will look up the filter details. I have a multiport valve that I can run in bypass mode, which I think will accomplish the goal (measure the flow with the filter removed from the loop) without disassembling anything. I will try that and gather more data. The chemical levels were poor when I bought the house, so it's possible the filter is in suboptimal condition. It has been backwashed periodically, but I know it hasn't been disassembled in a year or perhaps much longer.

I appreciate having an idea to try. I am busy tonight, but I'll reply with the data when I have a few minutes to try it.
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
41,197
Tucson, AZ
#5
Yeah, sounds like you have a filter issue if you have not broken it down for a good cleaning. You should do that at least once a year. And many people do not backwash and just do a full cleaning every time (1-2 times per year) because backwashing is not very thorough. Only add 80% of the full DE amount after just a backwashing series.

You can run in Recirculate mode to see the flow rates, but will then lose the filter pressures.

Check these out:
Use and Care of DE Filters
DE Filter Cleaning Tutorial
 

senex

Gold Supporter
Mar 20, 2018
10
Austin, TX
#6
Thanks for the ideas. It sounds like I need to clean that filter.

JamesW -- I updated my original post to add a column for the psi reported by the DE filter gauge. I hope that helps. fyi, before I installed the VSP, the DE filter gauge showed ~25psi when the JHPU2.0 was running right after a backflush procedure. (I am new to pool ownership, so I had a pool guy show me how to do it; I don't know if he followed the right procedures or not; he acted like it was fine.)

jblizzle -- what do you mean that recirc mode "will then lose the filter pressures"? Are you suggesting I shouldn't test in recirc mode?
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
10,218
Bedford, TX
#7
S,

I have the older model Intelliflo and here is my info for reference (psi is my filter pressure gauge..)

1100 rpm 150 Watts 2 psi (As slow as my pump can go...)
1600 rpm 338 Watts 5 psi
2000 rpm 599 Watts 8 psi
2600 rpm 1243 Watts 11 psi
3000 rpm 1877 Watts 14 psi

It appears the newer IntelliFlo uses less electrical power for a given speed.

I do not have a heater and I have a large cartridge filter, not DE, but filter pressure is about half of yours...

Thanks for posting,

Jim R.
 

JamesW

TFP Expert
Mar 3, 2011
12,677
#8
The filter definitely needs to be taken apart and cleaned.

What size is the filter?

What is the plumbing coming and going and how far to the pool?
 

senex

Gold Supporter
Mar 20, 2018
10
Austin, TX
#9
JamesW -- sounds good. I will disassemble and clean it.

I will look up the filter details and post some photos tomorrow. The equipment sits next to the deep end of the pool, centered, about 2 feet away from the pool wall. The pool is 17x32 feet, so the max run to anywhere is probably ~40'. Most of the pipes are 2", possibly bigger -- I will measure.

I tried to make a schematic diagram but it didn't work. I'll try to draw a diagram and upload it -- or maybe the photo will be adequate.
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
41,197
Tucson, AZ
#10
jblizzle -- what do you mean that recirc mode "will then lose the filter pressures"? Are you suggesting I shouldn't test in recirc mode?
I just meant that in Recirculate mode your filter will not be under pressure and thus you would not be able to compare the pressure values. Unlike if you just pulled out the grids and ran in Filter mode where you would get the pressure readings and allow you to see just how much the grids are impacting the pressure.

Check flows in Recirculate and get that filter broken down and cleaned. You can likely skip the running without the grids (that was before I knew you have a Multi-port valve).
 

senex

Gold Supporter
Mar 20, 2018
10
Austin, TX
#11
Thanks again for everyone's advice.

I updated my signature with equipment model numbers. (My DE filter is a 60 sqft Crystal Water).
I also measured my plumbing: most pipes are 2", except to/from spa is 2.5" and the line to the polaris port is 1.5".
(There is also a 1.5" line in parallel with the 2" inline feeder line, but that's a mystery for another day).

I redid a few tests while bypassing the filter. The flow increases significantly, which is a relief. Phew. I have high hopes for the data after a full DE filter cleaning.

Interestingly, when bypassing the filter, wattage was higher at a given rpm -- I didn't expect that. Flow rate increased more than wattage, so the important ratio (watts per gpm) improved. (I'm not troubled about this -- I'm just mentioning it because I found it interesting -- I don't have great intuition for fluid dynamics).

Here is a new chart with a few values I retested.

------------------ With DE filter active -------------------- Bypassing DE filter ----------
[TABLE="class: grid, width: 600"]
[TR]
[TD]RPM[/TD]
[TD]Watts[/TD]
[TD]GPM[/TD]
[TD]PSI[/TD]
[TD][/TD]
[TD]Watts[/TD]
[TD]GPM[/TD]
[TD]PSI[/TD]
[/TR]
[TR]
[TD]1000[/TD]
[TD]62[/TD]
[TD]7[/TD]
[TD]3[/TD]
[TD][/TD]
[TD]65[/TD]
[TD]9[/TD]
[TD]3[/TD]
[/TR]
[TR]
[TD]1600[/TD]
[TD]190[/TD]
[TD]12[/TD]
[TD]8[/TD]
[TD][/TD]
[TD]270[/TD]
[TD]30[/TD]
[TD]8[/TD]
[/TR]
[TR]
[TD]2000[/TD]
[TD]364[/TD]
[TD]18[/TD]
[TD]13[/TD]
[TD][/TD]
[TD]530[/TD]
[TD]44[/TD]
[TD]12[/TD]
[/TR]
[TR]
[TD]2400[/TD]
[TD]670[/TD]
[TD]27[/TD]
[TD]19[/TD]
[TD][/TD]
[TD]901[/TD]
[TD]57[/TD]
[TD]17[/TD]
[/TR]
[/TABLE]

In summary, I think we have lots of evidence that the DE filter needs a major cleaning. I will attempt it this weekend and report back with the results. Thanks again for the advice and ideas.
 

JamesW

TFP Expert
Mar 3, 2011
12,677
#12

senex

Gold Supporter
Mar 20, 2018
10
Austin, TX
#15
Where did the PSI numbers come from if you bypassed the filter?
Yep, JamesW is right.
My brand new Intelliflo has a digital readout that reports rpm, watts, gpm, and psi.
My filter has an analog gauge.
My original post has a table where I reported both values (digital from the pump display, analog from the DE filter gauge).
On bypass, the DE gauge was always zero, so I just reported the digital values from the pump lcd.
 

senex

Gold Supporter
Mar 20, 2018
10
Austin, TX
#16
The filter cleaning was a great victory -- I'm now very satisfied with the Intelliflo performance. Thanks to everyone for helping me solve my problem!

Some photos & data are below if you're curious.

It was difficult to remove the fins due to lack of clearance (the manual recommends 23" of clearance above the unit and I have 11"), but I managed to tilt it out. The fins looked like this (the clumps of DE are 3/4" to 1" thick):



This was after I had backflowed 3x to try to flush the DE. (Afterwards I realized that I had only been backflowing at 2600rpm, not the full 3500+, so maybe my backflows were substandard).

I'm not sure if that's a "normal" amount of DE for after a backflow, but it seemed excessive to me. As previously mentioned, it's been at least one year since the last cleaning, possibly much longer.

I followed TFP's [link=http://www.troublefreepool.com/threads/72506-DE-Filter-Cleaning-Tutorial]DE Filter Cleaning Tutorial[/link]. Everything went smoothly. It took about 3 hours of work because I went slowly & carefully (it's my first cleaning). I especially like the advice to mix the DE into a slurry before pouring into the skimmer. Our prior pool guy (before I found TFP) used to pour the powder directly into the skimmer, and I wonder if that promoted clumping on the filter fins.

The flow numbers look excellent after the cleaning:

--------------- Before DE Cleaning ------------- After DE Cleaning ------
[TABLE="class: grid, width: 500"]
[TR]
[TD]RPM[/TD]
[TD]Watts[/TD]
[TD]GPM[/TD]
[TD]PSI[/TD]
[TD][/TD]
[TD]Watts[/TD]
[TD]GPM[/TD]
[TD]PSI[/TD]
[/TR]
[TR]
[TD]1000[/TD]
[TD]62[/TD]
[TD]7[/TD]
[TD]3[/TD]
[TD][/TD]
[TD]60[/TD]
[TD]5[/TD]
[TD]3[/TD]
[/TR]
[TR]
[TD]1600[/TD]
[TD]190[/TD]
[TD]12[/TD]
[TD]8[/TD]
[TD][/TD]
[TD]242[/TD]
[TD]25[/TD]
[TD]8[/TD]
[/TR]
[TR]
[TD]2000[/TD]
[TD]364[/TD]
[TD]18[/TD]
[TD]13[/TD]
[TD][/TD]
[TD]490[/TD]
[TD]39[/TD]
[TD]12[/TD]
[/TR]
[TR]
[TD]2400[/TD]
[TD]670[/TD]
[TD]27[/TD]
[TD]19[/TD]
[TD][/TD]
[TD]840[/TD]
[TD]50[/TD]
[TD]18[/TD]
[/TR]
[TR]
[TD]3000[/TD]
[TD]1340[/TD]
[TD]41[/TD]
[TD]29[/TD]
[TD][/TD]
[TD]1630[/TD]
[TD]64[/TD]
[TD]28[/TD]
[/TR]
[/TABLE]

In some cases the flow doubled! This is terrific. I'm now going to get the 80%+ energy savings I anticipated -- and the much quieter operation.
(The flow at 1000rpm actually decreased, but I think that's because I still had air in the pipes when I took the new measurements at low rpm -- so I'm not concerned).

Thanks again for the great advice here.
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
41,197
Tucson, AZ
#17
Backwashing never really does a good job of clearing out the de. And after just one or two backwash and recharge Cycles you can also find the de all clumped up like in your pictures. Which is why if you can keep control of your Chemistry off and you can go the entire season without having to backwash and then just do a full break down once or twice a year.

I'm glad to hear you found my tutorial helpful! :cheers: