Should you use a vf pump

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dalehileman

Should you use a vf pump

Postby dalehileman » Sat 11 Sep, 2010 13:25

Notwithstanding the probability of drowning an interloper I advise no winter cover since it not only blocks your view of what might be going on underneath and requires occasional tedious sweeping of debris, in spite of a potentially reduced electric bill I also question the advisability of vf:

Since our inlets are at the head (W) surface flow carries flotsam to skimmer port at foot (NE) where it's deposited in the basket. Furthermore (for anyone considering new pool construction) our prevailing wind by the sheerest chance comes from exactly the right direction (SW)

Anyone considering vf, however, might judge whether a minimal flow rate might hinder the former action especially where a summer solar cover might limit the period during which this flow is possible

Apologize if the following is a breach of protocol but it's pertinent

http://ths.gardenweb.com/forums/load/po ... 99247.html


chem geek
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Should you use a vf pump

Postby chem geek » Sat 11 Sep, 2010 19:54

As Mark noted on the GardenWeb thread, with the IntelliFlo VF you can set the flow rate to whatever you want for whenever you want. Like him, I have solar on part of the time at 48 GPM so with 3 returns that's 16 GPM per return while with the solar off it's 26 GPM so around 9 GPM per return though I have an IntelliFlo VF. I haven't notice any problems with debris getting to the skimmer, but I have an electric safety cover on the pool so debris is only an issue for the 1-2 hours per day the pool is open on weekdays and the 3-4 hours per day on weekends. Even on windy days, most leaves and debris get to the skimmer, but our prevailing winds tend to be towards the direction of the skimmer anyway.
dalehileman

Should you use a vf pump

Postby dalehileman » Wed 15 Sep, 2010 14:27

Geek thank you for that report as we are considering vf

Wondering how you change pump speed, whether there's external electronics or simply a switch on the pump itself. If both how is the external electronics unit situated to protect it from the weather and are you confident when it fails that you will be able to easily fix it. For instance, will the maker likely remain in business and if so is it easily serviced, eg, by simply replacing a circuit board etc

Thanks once more
chem geek
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Should you use a vf pump

Postby chem geek » Wed 15 Sep, 2010 14:31

You can program some things on the pump itself -- up to 4 programs, I believe. However, if you want these programs to change based on external events, such as a thermal sensor for a solar system, then you'll need an external controller. Pentair offers several at different levels of sophistication and pricing. The controller is a circuit board and panel put into a metal box with a cover so is weather proof. In my case, all of my equipment is in a pool shed designed for that purpose so this isn't a problem.
dalehileman

Should you use a vf pump

Postby dalehileman » Thu 16 Sep, 2010 15:04

geek thanks for that report. If you can program your pump I assume that means it uses semiconductor logic and switching which in an environment like mine--the Mojave Desert--bodes ill with future maintenance. I had hoped to find a simple, inexpensive vf with no semiconductors but only mechanical switches to vary its speed. During the time I worked in the Electronics Industry high-voltage high-current semiconductor devices weren't very reliable even in a laboratory environment but from what I've heard so far evidently nobody else shares my apprehensions so maybe the sort of simplistic pump I imagine doesn't even exist today

Still I hope given no choice in the matter that its maker is well established and that the semiconductor electronics is easily and inexpensively replaced but thank you once more for your input
dalehileman

Should you use a vf pump

Postby dalehileman » Thu 16 Sep, 2010 15:12

TO geek but by the way in a fabulous modern forum like this with intricacies such as confirmation codes etc how on earth does one edit one's post if previewing doesn't catch all the errors and typos
chem geek
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Should you use a vf pump

Postby chem geek » Thu 16 Sep, 2010 19:21

There should be an "Edit" button to the left of the "Quote" button in the upper right of every post that you have written.

As for the IntelliFlo VF electronics, I believe they are a unit that can be replaced separately (i.e. they attach to the pump), but you should contact Pentair about that and about your specific operating conditions.
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mas985
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Should you use a vf pump

Postby mas985 » Fri 17 Sep, 2010 09:58

A two speed pump doesn't use any electronics other than a second set of windings in the motor and perhaps a capacitor or two. A mechanical switch is sometimes used to switch between speeds but you can also use a mechanical timer to switch between speeds. Mutliple speeds without electronics requires a multi-pole motor which beyond 4-poles (2-speeds) is hard to come by and probably very expensive.

As to the VF electronics, I have seen the drive advertised but the prices seem to be about 2/3rds the cost of the entire pump.
Mark
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dalehileman

Should you use a vf pump

Postby dalehileman » Fri 17 Sep, 2010 10:17

chem geek wrote:There should be an "Edit" button to the left of the "Quote" button in the upper right of every post that you have written.

You're right, there should be, but there isn't


As for the IntelliFlo VF electronics, I believe they are a unit that can be replaced separately (i.e. they attach to the pump), but you should contact Pentair about that and about your specific operating conditions.


Thanks I will look into that but in the meantime do you understand that this external unit is necessary for speed control, in other words, if you had no need for the kind of complex programming it provides (depending only on the existing timer), could you acquire the pump without that accouterment
chem geek
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Should you use a vf pump

Postby chem geek » Fri 17 Sep, 2010 12:14

I don't believe so, but ask Pentair about your options. As Mark pointed out, a 2-speed pump wouldn't need special electronics and would be less expensive as well, though you obviously don't get the full variable speed range nor as high efficiency at lower speeds compared to the IntelliFlo.

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