IntelliFlo Low Flow Rates

andyoi630

Well-known member
Aug 30, 2013
125
Maryland
Hey all,

Last summer I completed my Owner build of a 900 sq ft free form pool. I have 4 IntelliFlo XFs and my main filtration one has given me issues with flow since day one. At 3400 RPM in pool mode, I can’t get north of 70 GPM no matter what I try.

Main pump services pool and spa. Pool side, there is a 3” main drain suction, and 2x 2” skimmer lines. On the return side, every return is individually plumbed - so that’s 8x 1.5” returns and 4x 2”.

In addition to IntelliFlo, I have a Quad DE 100 filter with no multi port valve, propane heater and heat pump.

In normal operation, with bare minimum flow going through heaters to trigger them, I’m at around 55-60 GPM at 3400 rpm with a clean filter. 48-50 GPM at 2800 rpm.

I have tried completely blocking off the heaters and removing the filter cartridges and internals, and I still cannot exceed 70-72 GPM at full speed. Based on pump curve I fully expected well over 100 GPM and designed my infloor off of 90.

My spa booster pump achieves 95 gpm at the top end, and I think that’s more jet limited than anything (12 jets on that).

Any thoughts? It really makes my in floor completely useless.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
22,805
Bedford, TX
Andy,

Let's call someone that can help... @JamesW

I am puzzled why you need so much flow.. I run my pool as 1200 rpm, which I guess is about 25 GPM..

Thanks,

Jim R,
 

andyoi630

Well-known member
Aug 30, 2013
125
Maryland
Thanks Jim.

In floor system mainly. It’s designed for 90 gpm.
But even beyond that, my chlorinator got plumbed in on the heater loop so need significant flow just to trigger it.

Its odd though. Had a regular IntelliFlo at my old pool and run 1500 rpm. Now I’m over double that...
 

JamesW

TFP Expert
Mar 2, 2011
27,649
Do you have pictures of everything?

What is the filter pressure, the pressure reading directly from the pump and the reading from the cleaning system?

Check the cell for debris.
 

Turbo1Ton

Gold Supporter
Dec 26, 2019
663
NE Oklahoma
Pool Size
14500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Just offering something to look at. 90 GPM seems really high for the IFCS. My IFCS was designed for 48 GPM. Granted my pool is only ~500sf ish. I would have thought they would have broken the system up into more zones in order to achieve lower required flow rates. Although I'm not sure if that is really how that would work.

--Jeff
 

JamesW

TFP Expert
Mar 2, 2011
27,649


You might want to do a 5 psi check valve bypass in parallel with the heaters since they have so much head loss.

This will automatically bypass excess flow around the heaters.

Make sure that the heaters are not clogged up.

Check the screens in the cleaner valve unions.

What flow and pressure are specified for the cleaning system?

Note that you don't want to run the system without filters because debris can clog the equipment past the filter.
 

andyoi630

Well-known member
Aug 30, 2013
125
Maryland
Just offering something to look at. 90 GPM seems really high for the IFCS. My IFCS was designed for 48 GPM. Granted my pool is only ~500sf ish. I would have thought they would have broken the system up into more zones in order to achieve lower required flow rates. Although I'm not sure if that is really how that would work.

--Jeff
I was slightly off, pulled up the original specs. A&A designed the in-floor for 82 GPM, it's 9 zones + 2 venturi skimmers. 898 sq ft pool
 
Last edited:

andyoi630

Well-known member
Aug 30, 2013
125
Maryland
Took a bunch of measurements and pictures:

In normal operation, my heater/Chlorinator bypass is set to send the minimum through the heaters for them to trigger flow (same with chlorinator). Now, one issue is that those are tied together so I have to send water through the heaters to chlorinate the pool.

In that operation, the following measurements:

1800 RPM, Filter reads 3 PSI, Pump reads 11 PSI, 27 GPM
2900 RPM, Filter reads 12 PSI, Pump reads 28 PSI, 50 GPM (My typical speed to get enough flow for spillover/chlorinator)
3400 RPM, Filter reads 18 PSI, Pump reads 39 PSI, 59 GPM

If I send ALL water through heaters/chlorinator:

1800 RPM, Filter reads 8 PSI, Pump reads 11 PSI, 16 GPM
2900 RPM, Filter reads 19 PSI, Pump reads 28 PSI, 38 GPM
3400 RPM, Filter reads 25 PSI, Pump reads 39 PSI, 46 GPM

If I fully bypass heaters and chlorinator:

1800 RPM, Filter reads 1 PSI, Pump reads 11 PSI, 36 GPM
2900 RPM, Filter reads 8 PSI, Pump reads 28 PSI, 57 GPM
3400 RPM, Filter reads 11 PSI, Pump reads 39 PSI, 65 GPM

So, I'm in a situation where fully bypassing all major equipment, I still am no where near what I'd expect. I have taken apart nearly every valve to check for a blockage, I've even scoped lines on the equipment pad. Happens whether I pull from main drain and/or skimmers and/or spa drain.

In the picture below, the farthest right pump is the main filter pump. It has 2 skimmers and Main drain coming in, along with spa drain - leading to A&A Leaf Skim basket. From Filter it goes to a bypass valve, then (behind the wall), heat pump then gas heater, check valve, then to IC60, then to return manifolds on the far right.

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Also maybe a side question - anyone know how to make the Intellicenter app less awful?
 

JamesW

TFP Expert
Mar 2, 2011
27,649
Is your heater bypass partially open?

I would put the cell downstream of the bypass so that it works regardless of whether or not the heaters are bypassed.

I would put a 5 psi check valve bypass on both heaters.

I would put a flow switch on the inlet to each heater.

I would install a real flow meter to see what the actual flow is.

I would install a vacuum gauge on the suction to see what that is.

The pressure readings might indicate a suction issue or maybe a clogged impeller.
 

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JamesW

TFP Expert
Mar 2, 2011
27,649
3400 RPM, Filter reads 11 PSI, Pump reads 39 PSI, 65 GPM
That's such a big difference that it's either incorrect or the suction has to have an issue.

I would check the impeller.

The vacuum pressure and the filter pressure should add together to equal the total system pressure reported by the pump.

I would check the vacuum pressure and the actual flow with a real flow meter.

The pump just estimates the pressure and flow from the power usage. So, I don't think that it's super accurate.

Check the salt cell for clogs.

Check the cleaner head screen.

Chris the heater intakes for debris.
 

andyoi630

Well-known member
Aug 30, 2013
125
Maryland
Why do you have an extra strainer in front of the pump?

Are the strainers clean?
That strainer is an A&A LeafSkim which is part of the in floor to catch larger volumes of debris before the pump. They’re clear, I clear them every day or two.
 

andyoi630

Well-known member
Aug 30, 2013
125
Maryland
That's such a big difference that it's either incorrect or the suction has to have an issue.

I would check the impeller.

The vacuum pressure and the filter pressure should add together to equal the total system pressure reported by the pump.

I would check the vacuum pressure and the actual flow with a real flow meter.

The pump just estimates the pressure and flow from the power usage. So, I don't think that it's super accurate.

Check the salt cell for clogs.

Check the cleaner head screen.

Chris the heater intakes for debris.
So is the pump in theory calculating vacuum pressure? I ripped apart the pump yesterday and didn’t see any signs the impeller was clogged up.

On suction side, I’ve checked every valve for a blockage, and I get the same results whether I pull from skimmers or either pool or spa main drain - so I don’t particularly think anything is stuck in the lines.
 

JamesW

TFP Expert
Mar 2, 2011
27,649
So is the pump in theory calculating vacuum pressure?
It's "estimating" the total system pressure based on the power usage and the rpm.

Theoretically, the total system pressure is the suction pressure and the return pressure added together.
 

andyoi630

Well-known member
Aug 30, 2013
125
Maryland
I’ll try and figure out how to best do that, don’t have a lot of room. Thank you.
I took a look at spa pump next to it, which is pretty simple with few valves - shows 37 psi at full speed - and about 90 GPM.
 
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