Proper pump speed for VS pump?

[dufus]

I've been getting conflicting opinions about what rpm's I should be running my brand new pentair VS-3050 pump.

I've got a 12K gallon pool and the skimmer is about 35 feet from the equipment and is a straight shot. It's a pretty standard pool with no spa and is basically a rectangle with a 6foot deep end. The filter is a pentair 420 cartridge (150 GPM). We are using a vacuum cleaner and it is using one of those skimmer\main drain setups where most of the suction is thru the skimmer and nothing really goes thru the main drains. We also have an intellichlor IC40 (my pool guy told me to buy the big one) which from what I read needs at least 25GPM to operate.

Can someone recommend a ballpark rpm setup for this configuration? I've got one guy telling me about 2300 rpm and one guy telling me that 1000 rpm is fine. I'm sure it's more scientific than this....

Thanks, Chris

 

[mas985]

The short answer is what ever works. The most efficient setting will be around 1000 RPM but that may not be fast enough for your skimmers and/or cleaner. Try 1000 and if it isn't working for you then up the speed some.

Here are some rough approximations for flow rate depending on your plumbing size:

Intelliflo on 1.5" Plumbing: Flow Rate (GPM) = RPM / 45
Intelliflo on 2.0" Plumbing: Flow Rate (GPM) = RPM / 35
Intelliflo on 2.5" Plumbing: Flow Rate (GPM) = RPM / 30

 

[dufus]

Thanks for the info. When I do a calculation for a 4 or 5 hour turnaround (its hot here in Las Vegas), it would give me an rpm of about 1800. If I set it to 1800, the skimmer is barely sucking water and the pressure gauge on top of the filter is barely five pounds. I always thought the norm on the filter would be around 10 psi... hmm..

 

[mas985]

Filter pressure is dependent on RPM as well.

Lower RPM --> Lower GPM --> Lower Head Loss --> Lower Filter Pressure

One of the downsides of lower GPM is that the skimmers do not work as well but that is usually worth the sacrifice to get lower energy use. One solution is to run the pump at higher speeds for a short time each day but use the lower speeds most of the time.

 

[brg88tx]

i just keep mine on speed #2 most of the time (1500 rpm). uses about 300 watts at that speed.

 

[JamesW]

If I set it to 1800, the skimmer is barely sucking water and the pressure gauge on top of the filter is barely five pounds.

I would think that at 1800 rpm one single skimmer should be working fairly well. Perhaps there is something not working correctly or misconfigured.