Jandy ePump 2.0 flow rate

[zhenya]

I am new to pool ownership and desperately looking for help. I have a new Jandy variable speed pump - ePump JEP 2.0
Where can I find some kinds if chart or a table that shows the flow rate (GPM) at various speeds. I am trying to figure out how long I should be running my equipment and at what speed.

Thank you.

 

[jblizzle]

It is not that simple. The flow rate is a function of the pump speed and the the total head loss throughout your plumbing and equipment. Generally there is no need to know the flow rate. For the cheapest electrical cost, you want to be running at the lowest possible speed that allows your pool's features to work.

This may offer more insight: pool-school/pump_run_time

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[zhenya]

Thank you for the response. I read the article you pointed me to but I think it's even more confusing. This being a SW pool would mean that I have to have a certain flow for the salt cell to function. Also not knowing the GPM how can I estimate how long the pool should run for at any speed?

 

[jblizzle]

Most SWG require pretty low flow rates to work, if you have the pump very low and get a no flow warning, then adjust the speed up a bit. That is the advantage of the VS pumps. I would suggest trying about 1000 RPM as that is close to the most efficient speed and see if the SWG is happy.

Read the article again.

You need to run the pool long enough so that it is filtered enough for your liking. There is not minimum amount of water that needs to be moved. Just keep in mind that the longer you run the pump (at a low speed) you will need to lower the SWG as well to maintain the same FC level.

 

[poolkid]

Here's the flow chart published by Jandy.

As Jason pointed out, you'll need more information to calculate your flow rate. Specifically, you'll need to calculate your TDH at various RPMs.

Even then, it's not 100% accurate. A properly installed flow meter is about the only way to get a fairly close flow rate.

Steve

 

[mas985]

Standard flow meters are actually very poor at determining flow rates. Most quote an accuracy of 10% of full scale which can be as high as 10 GPM. The check valve flow meters are a little better at about 2% of full scale. However, I have a few spreadsheets that can get pretty close to actual flow rates by using the filter pressure and a description of the suction side plumbing.

But I agree with JB that there really is no need to know flow rates. Flow rate has little to do with required pump run time.