Is using Low speed 750 rpm on variable speed pump okay?

[clinthuey]

Is there any reason I can't run my Intelliflo i1 pump at the factory default speed of 750 rpm (speed 1) for 10 hours to do my daily circulation? Using the graph of flow rates for this pump available on the "More" tab of Pentair's webpage, it seems that I can get 20 gpm, roughly 10 hours to do a complete water turnover. This is without the Kreepy Krauly attached and without diverting water to the roof panels:

http://www.pentairpool.com/pool-pro/pro ... mp-451.htm

At this speed my pump LCD screen shows that I am using only 100 watts. I have only seen posts mentioning using 1000 rpm or higher. The temperatures in the summers here (next to Oakland, CA) don't average more than about 70 degrees.

I am currently trying to only run my Kreepy Krauly cleaner on a weekend day for 3 hours at 2000 rpm, good enough for a water turn-over. In the past raccoons have bitten into my cleaner hose causing my last pump, a WhisperFlo to run dry and damage the seals so doing the cleaning on weekends allows me to monitor the start-up. I generally don't get much debris in the pool.

The variable speed pump was just installed a week ago so I won't know yet how well the algae will be kept in check with the EcoSmarte non-chlorine system (requires pH 6.8) and the sand filter with glass media.

 

[JasonLion]

Welcome to TFP!

Running the pump at 750 rpm will work just fine. It will however use more total electricity than running around 1000 rpm for a shorter time (and moving the same total amount of water). I doubt this will come up, but occasionally you run into a skimmer that needs a higher flow rate to work correctly. Even at the lowest speed this shouldn't be an issue, but if you do notice problems with the skimmer not skimming effectively, try turning up the speed a little.

I really strongly don't recommend the EcoSmarte system. Copper is very prone to causing unsightly and difficult to remove stains, the low PH can damage your pool, and it does nothing to prevent person to person disease transmission through the water.

 

[clinthuey]

Welcome to TFP!

Running the pump at 750 rpm will work just fine. It will however use more total electricity than running around 1000 rpm for a shorter time (and moving the same total amount of water). I doubt this will come up, but occasionally you run into a skimmer that needs a higher flow rate to work correctly. Even at the lowest speed this shouldn't be an issue, but if you do notice problems with the skimmer not skimming effectively, try turning up the speed a little.

I really strongly don't recommend the EcoSmarte system. Copper is very prone to causing unsightly and difficult to remove stains, the low PH can damage your pool, and it does nothing to prevent person to person disease transmission through the water.

Looking again at the pumps flow rate curves, I'm estimating that running the Intelliflo i1 at 1000 rpm, I can do a water change in 6 hours. (The 750 rpm can actually do it in 8.7 hours compared to 5.9 hours at 1000 rpm.) I just went to the pump and tried this setting to see what the power consumption was for 1000 rpm. It jumped between 135 watts and 190 watts, which averages around 160 watts. I suspect that because the flow rate through the fine Vitro Clean glass media is very slow that sometimes the flow rate into the filter will exceed what can pass through. When I multiply the power consumption times the running time for the two speeds, I actually get a better energy saving at the slower speed.

I check my copper levels at around 5 ppm and haven't noticed copper staining on my old plaster pool. How can pH 6.8 damage my pool? Regarding person to person disease transmission, our family doesn't use the pool but a half dozen days out of the year.

 

[JasonLion]

Both the watts number displayed by the pump, and your flow rate estimates are subject to quite a bit of error. The pump is indeed more efficient at 1000 RPM than it is at 750 RPM, though the difference is fairly small.

 

[mas985]

clinthuey,

The wattages you are quoting are more consistent with the Intelliflo VS not the i1. The i1 should be much less like 75 watts at 750 RPM. Are you sure you have the i1?

Note too, you cannot use the Intelliflo VS charts for the i1. Different head curves and power curves.