Intelliflo VF Questions

Jump to latest Follow Reply
I looked at the spread sheet. I may be reading it wrong but it looks like at 3450 RPM and 0 GPM, which is a dead headed pump, the wattage used is less than a non-dead headed system.

I would expect the strain from the dead head to consume more, not less. What am I missing?

Scott
PoolGuyNJ
 
I struggled with that at first, too. A pump pushing no water is doing less "work" than a pump pushing a lot of water. Hence, as PSI rises, electrical consumption actually goes down on a continuous speed pump.

For me, that's not intuitive until you work with it a time or two.
 
duraleigh said:
I struggled with that at first, too. A pump pushing no water is doing less "work" than a pump pushing a lot of water. Hence, as PSI rises, electrical consumption actually goes down on a continuous speed pump.

For me, that's not intuitive until you work with it a time or two.
Click to expand...

That is correct.

It is somewhat counter intuitive but the pump will consume less energy at the left most point on the head curve and consume the most energy at the right most point of the head curve. This has to do with the difference between potential energy (pressure) and kinetic energy (flow rate). The power required to drive the pump (pumping HP) is related to the product of the head and flow rate.

At dead head there is no flow rate and only pressure so technically there 0 pumping HP delivered. However, because of the recirculation loss in the impeller, friction loss in the pump and motor and IR2 losses in the motor, there is still quite a bit of consumed energy. More than what would be in a free running motor but less than a fully loaded motor. Pump designers will usually target the service factor HP to be the run out point on the pump which is usually the right most point on the head curve. This is where the pump will draw the most current but not necessarily the best pumping efficiency.

A good example of this phenomenon is to look at the energy curve of the Intelliflo shown in the manual here on page 47. Note how the power increases nearly linearly with increasing flow rate. The minimum power consumption is at dead head for each RPM value.

Here is a pretty good article written by Joe Evans which explains this in much more detail.
 
117 watts is really low- maybe to low? (question because I'm not sure)

After running a battery of tests on my own pool Ive come to the conclusion that below a certain RPM/Watt power consumption level there simply isnt enough flow for good skimming action hence (heres where I need some opinions) On my particular pool 200 watts seems to be the lowest flow at which everything "works"

Below this setting 2 things happen

1. My chlorinator give me a low flow warning. Im not sure if its still producing or not , but I would assume the warning s there for a reason.
2. Im not really "skimming" anymore. Below 200 watts my skimmer weir starts to bob and cycle as opposed to producing a smooth continuous inflow.

Is 117 a realistic working figure?

Thanks.

UD
 
Just how slow you can run the pump varies from pool to pool. You need to maintain enough flow to keep the SWG happy, so that is probably the limiting issue in your setup. Others might not have that particular issue.

You can work around the "not skimming" problem by speeding up the pump for 10 minutes every couple of hours. Of course, to do this you may need a fancy timer or an automation system that supports many different pump run times with different speeds.
 
JasonLion said:
Just how slow you can run the pump varies from pool to pool. You need to maintain enough flow to keep the SWG happy, so that is probably the limiting issue in your setup. Others might not have that particular issue.

You can work around the "not skimming" problem by speeding up the pump for 10 minutes every couple of hours. Of course, to do this you may need a fancy timer or an automation system that supports many different pump run times with different speeds.
Click to expand...


Totally agreed on the "pool to pool" differences.

Does the intelli-touch/easy touch offer this or some other style of 10 minute "bump" capability?

Who amongst these boards currently holds the low wattage record.
ie are guys really going down to that low of a wattage/flow level and sustaining this?

Thanks!

Dave
 
You can schedule a "feature" to turn on that simply uses a higher flow rate. However, it's a pain to set up since you have to program each 10 minute interval that you want separately (i.e. there isn't any "turn on for 10 minutes every hour" feature). At least this is how it works on my Intellitouch (I don't do this boost feature, but can see how I could make it work since I do have "features" for higher flow rates I sometimes use on demand). Note that a "feature" doesn't mean a real feature like a waterfall -- it can just be a higher flow rate and not turn on any valves or do anything else.
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply