# Variable speed pump speed to push water up to the roof

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• Last Post 01 November 2016
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Afshin posted this 30 October 2016

I have solar heating for my pool. The water is pushed to my roof which is 13 feet higher than the pool level through the pump. My questions is: What speed shall I choose for the pump (when solar heat is activated) so it won't go through a lot of pressure when pushing the water up to the solar heating system? I am using Intelliflo Variable Speed Pump:

http://www.pentairpool.com/pdfs/IntelliFloVSOM.pdf

In fact, how do you mathematically calculate that?

Thanks

InyoRob posted this 31 October 2016

Hello Afshin - We'd be glad to assist you. Since every pool system is different, there is not a set speed for solar panels. You'll need to figure out how many gallons per minute your solar system will require. Most panels require 3-5 gpm per panel. Count the number of panels and multiply that by 3-5. This will provide you with correct operating gpm.

You will then need to figure out how many gpm your pump is pushing at a given speed. You can use the pumps curve chart (page 27 in manual) to figure this out or you can install a flow meter. The flow meter is the easier way to get an accurate reading.

Flow Meter Example: If you have 8 panels you can multiply 8 (panels) x 4 (gpm average). This equals 32. So you need to set the pump at a speed that provides 32 gpm. Start the pump on a low speed and work up until the flow meter reads 32 gpm. Note what speed reached 32 gpm and you are all set.

Afshin posted this 31 October 2016

Thank you very much for your detailed Info InyoRob. They were significantly helpful. I will try it today and let you know how it goes. Does it hurt the panels if the speed is set higher that what you explained above, or it is just the lower speed that hurts the pump?

InyoRob posted this 31 October 2016

Too much water flowing through them could cause damage to the panels. Double check the designed flow rate of those panels

On the other hand, too low of a speed may not push the water up to the roof.

Afshin posted this 31 October 2016

Thank you very much. That was very useful. I also was checking the pumps curve chart (page 27 in manual) to calculate the speed. How do you calcualte the "Total Dynamic Head in FT" of water for pushing the water 13 FT above the pool level?

InyoRob posted this 01 November 2016

We have a couple different guides that explain how calculate total dynamic head.

How to Measure Total Dynamic Head with Gauges

How Do I Calculate Feet of Head for My Pool