Please Help with Low Flow Issue - IntelliFlo VSF Pump - Pics Included

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J

jkozlow3

Member
Apr 1, 2021
16
San Diego
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Hello everyone!

I could really use some help diagnosing possible causes of low flow/gpm in our system.

We moved into this house in early 2021. The pool is somewhere in the neighborhood of 15-18 years old and is probably ~20,000 gallons based on my very rough calculation (including the built-in spa with spillway).

Whenever the pump runs, the spa spillway creates a nice water feature effect which we really like. We live in San Diego and have the doors open to the backyard much of the year, so I wanted to basically have the pump & spillway running from 7a-11p every day (killing 2 birds - for both ambiance as well as cleaning/filtration). As a result, I thought it would be wise to replace the aging single speed pump with a variable speed pump, figuring it would pay for itself quickly - especially since our electric rates are insane (we pay an average total blended rate of ~0.40/kWh).

Upon moving into the house, we retained the pool guy that's been working on this pool for many years and he swapped out the pump with a Pentair IntelliFlo VSF and installed a Pentair SWCG last Spring/Summer.

The ScreenLogic app displays the approximate GPM for any given speed. My understanding from reading some threads here is that this is a calculated/approximate value based on the wattage being used by the pump, etc.

Our GPM numbers with the VSF pump seem a bit lower vs. what many others have posted here after searching through some past threads. The filter was cleaned 3 months ago (the pool guy cleans it twice per year).

For example:

RPMWattsGPMFilter Pressure
1800260168
2000360209
23506003011
25007203312
280010254014

The SWCG needs a minimum GPM (~25 GPM), as does the Hayward suction cleaner in order to be effective (~30+ GPM), as does the Pentair MasterTemp 400 heater (40 GPM minimum according to the manual). I also like to achieve 1 turnover per day (I realize many here say this is not necessary, but 1 turnover a day is basically a given anyway if I run the pump for 16 hours a day for the spillway water feature ambiance effect).

Ideally, I’d love to boost the GPM flow rate so that I can run the pump at lower RPMs and use less electricity. What could be holding us back? Are there issues you see with the way the system is plumbed that could be causing issues? Are the valves set correctly? I'm a bit of a novice at anything equipment-related. Pics attached.

Appreciate any assistance you can offer if there’s something you think we could change that might make a significant difference or more troubleshooting steps you think I should take.

Thanks!

IMG_5278.jpg IMG_5279.jpg IMG_5281.jpg
 
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There is nothing you can do to significantly get more flow from lower RPM given your setup. It is baked into your pipe sizes, plumbing zigs and zags, and your filter and heater. Making minor changes in the plumbing will not give you a big increase in flow.

Your IntelliChlor is installed with a downward flow. Pentair recommends it be installed on the other side of the loop with an upward flow. The way yours is the flow switch can fail closed and leave your cell powered with the pump off and no flow. That creates a cell explosion risk.

1641765543248.png

1641765543248.png


If you install a heater bypass and bypass the heater when not in use you will get more flow. The heater is a major restriction in your plumbing.

Heater Bypass - Further Reading

www.troublefreepool.com www.troublefreepool.com

How old are your filter cartridges? I would consider getting a new set of cartridges and seeing if you get a flow increase.

Those are things you can try but I don’t think they will make a big difference.

Let us know what your experiments find.
 
ajw22 said:
Your IntelliChlor is installed with a downward flow. Pentair recommends it be installed on the other side of the loop with an upward flow. The way yours is the flow switch can fail closed and leave your cell powered with the pump off and no flow. That creates a cell explosion risk.
Click to expand...

That doesn't sound good!

The IntelliChlor is wired to one of the Aux circuits on the board and cannot be powered on unless the pump is also on (i.e. I can choose to run the SWCG during a subset of the time the pump is running). Is there still an explosion risk in this case if the SWCG isn't receiving power when the pump is off? Do you know if the way it's currently installed is prohibited by Pentair vs. not recommended? If it's prohibited, I can definitely have the guy who installed it fix it.


ajw22 said:
If you install a heater bypass and bypass the heater when not in use you will get more flow. The heater is a major restriction in your plumbing.
Click to expand...

Thanks - I'll look into that.

ajw22 said:
How old are your filter cartridges? I would consider getting a new set of cartridges and seeing if you get a flow increase.
Click to expand...

Not sure - I can ask the pool guy.


Appreciate the info!
 
jkozlow3 said:
Thanks!

The IntelliChlor is wired to one of the Aux circuits on the board and cannot be powered on unless the pump is also on (i.e. I can choose to run the SWCG during a subset of the time the pump is running). Is there still an explosion risk in this case if the SWCG isn't receiving power when the pump is off?
Click to expand...

Yes, what if the pump motor fails. Pump is powered but not running.

jkozlow3 said:
Do you know if the way it's currently installed is prohibited by Pentair vs. not recommended? If it's prohibited, I can definitely have the guy who installed it fix it.
Click to expand...
Pull up the IntelliChlor installation manual from the Pentair website. The pic above is from the manual.
 
mknauss said:
The Intellichor should be wired through the pump/filter relay so it only operates when in Pool/spa mode.
Click to expand...
Power to the LINE side of the AUX relay could come from the LOAD side of the pump/filter relay and be ok.

The devil is in the details. To know if this is a problem we need to see how things are wired.
 
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mknauss said:
The Intellichor should be wired through the pump/filter relay so it only operates when in Pool/spa mode.
Click to expand...

Correct. It's wired to where it cannot be operated except in pool/spa mode, but I can independently turn it on/off by powering the Aux circuit. The associated Aux circuit cannot be powered on UNLESS it's in pool/spa mode however (which in turn powers the Aux circuit). I asked the guy to wire it this way so that the SWCG wasn't running 16 hours a day if I have the pump running 16 hours/day. I can program the SWCG to run for 4/6/8 hours per day during a subset of the time that the pump is running.
 
That is fine. One can use a feature circuit to achieve the same thing in running the pump but not in pool mode.
 
jkozlow3 said:
Correct. It's wired to where it cannot be operated except in pool/spa mode, but I can independently turn it on/off by powering the Aux circuit. The associated Aux circuit cannot be powered on UNLESS it's in pool/spa mode however (which in turn powers the Aux circuit). I asked the guy to wire it this way so that the SWCG wasn't running 16 hours a day if I have the pump running 16 hours/day. I can program the SWCG to run for 4/6/8 hours per day during a subset of the time that the pump is running.
Click to expand...

That really is unnecessary. Wear on the SWG comes from the amount of chlorine generated and not the time it is powered.

If your pool needs 3 ppm of chlorine every 24 hours the water is the same if you generate it over 16 hours or 4 hours.

Letting your SWG generate chlorine the entire time your pump is running is the best way to manage it.
 
ajw22 said:
That really is unnecessary. Wear on the SWG comes from the amount of chlorine generated and not the time it is powered.

If your pool needs 3 ppm of chlorine every 24 hours the water is the same if you generate it over 16 hours or 4 hours.

Letting your SWG generate chlorine the entire time your pump is running is the best way to manage it.
Click to expand...

Understood. I just find it easier to run the SWCG for a set time and percentage output each day (i.e. 8 hours @ 30% in the Summer) vs. a potentially moving target (i.e. if I decide to change my pump schedule from 16 hours/day to 12 hours/day on certain days of the week, I'd need to adjust the SWCG accordingly).
 

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ajw22 said:
If you install a heater bypass and bypass the heater when not in use you will get more flow. The heater is a major restriction in your plumbing.
Click to expand...

Wow, in this thread (Verifiable Benefits of a Heater Bypass Install), some people saw huge increases in GPM/decreases in wattage after installing a heater bypass - sounds like something to look into for sure!
 
What automation system do you have?

I run my pump 24/7 at 1700 rpm. That gives a flow that works for my IntelliChlor and MasterTemp heater.

Does your IntelliChlor not give green lights and heater run with your pump at 1800-2000 rpm?
 
ajw22 said:
What automation system do you have?

I run my pump 24/7 at 1700 rpm. That gives a flow that works for my IntelliChlor and MasterTemp heater.

Does your IntelliChlor not give green lights and heater run with your pump at 1800-2000 rpm?
Click to expand...

No way - I wish!

1800 RPM is only around 16gpm according to the ScreenLogic app. I need 2200-2300 RPM to satisfy IntelliChlor (going by the green & red lights). I need 2800 RPM to achieve the MasterTemp 400's minimum 40 GPM (according to ScreenLogic), so I have "Either Heater" set to 2800 RPM at the moment.

Per your suggestion and the link I pasted in my post above, some people seem to see huge improvements with a heater bypass - perhaps this is something I should look into!
 
I would be very suspect of your filter cartridges. What is the clean filter pressure at your normal rpm? At what filter pressure are they cleaned?
 
I don’t pay attention to the GPM. I just use whatever RPM works. My pool is closed so I can’t look at it now.

I am suspicious of how good your cartridges are. If they are old then they could be clogged and restrictive.

For the SWG you should determine the minimum RPM that gives you the green flow light. That RPM +100 to 200 rpm is your minimum flow for the SWG.

For the MasterTemp heater I think Pentairs 40gpm minimum is conservative. I run my MasterTemp with less flow and no ill effects. What you need to do is put your hand around the manifold and output pipe. They should be barely warm to the touch and not hot. As long as the output pipe is not hot you have enough flow.
 
mknauss said:
I would be very suspect of your filter cartridges. What is the clean filter pressure at your normal rpm? At what filter pressure are they cleaned?
Click to expand...

I normally run the pump at 2350-2500 RPMs when not heating. The filter pressure is 11 & 12 psi at these RPMs (see first post).

The filter was cleaned ~3 months ago and is due for another cleaning in 3 months.
 
ajw22 said:
I don’t pay attention to the GPM. I just use whatever RPM works. My pool is closed so I can’t look at it now.

I am suspicious of how good your cartridges are. If they are old then they could be clogged and restrictive.

For the SWG you should determine the minimum RPM that gives you the green flow light. That RPM +100 to 200 rpm is your minimum flow for the SWG.

For the MasterTemp heater I think Pentairs 40gpm minimum is conservative. I run my MasterTemp with less flow and no ill effects. What yiu need to do is put your hand around the manifold and output pipe. They should be barely warm to the touch and not hot. As long as the output pipe is not hot you have enough flow.
Click to expand...

Good info. I'll test that out at some point.

I'll ask the pool guy about our filter cartridges the next time I see him. How often are they typically replaced? He cleans them twice a year, but he hasn't said anything about them needing replaced.
 
As a test pull the cartridges out of the filter, reassemble the filter without the cartridges, and see what your flow is at various RPMs.
 
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