New variable speed pump - what should the de filter pressure be?

[neen01]

We replaced our single speed pentair whisperflo 1.5hp pump with a Pentair IntelliFlo 011018 3HP Variable Speed Pump w/ Timer.
We opened the pool this week and now i realized that when the pump is on different speeds the de filter pressure is crazy different.
What is a good starting pressure - is it the one when its on max? When do we backwash?
I think the old one started around 18 and we backwashed around 22.

 

[Jimrahbe]

When the filter is clean, adjust the pump speed so that the pressure is about 15 or so, the specific PSI is not all that important. Record what the RPM is. Use this RPM as your reference point in the future when you are checking the pressure.

Personally, I never backwash anymore. With the pump running at low speed most of the time, I find it easier to just tear them apart twice a year and clean them. I also do that with the cartridge filter I have at my house.

Jim R.

 

[mas985]

Filter pressure will be proportional to the RPM^2 so you will get a wide range of pressure values as you change speed.

 

[neen01]

hmm ok i was more worried because i know if the filter runs high then something might be wrong with it so since its the beginning of the season and its 10 yrs old i wanted to make sure i wasn't missing a sign of something wrong.

 

[Jimrahbe]

I doubt if anything is wrong with it, but I bet when you first turn the pump on the Pressure gage goes up to 30 or more. At what RPM does the "clean" pressure get to 10? My guess is about 2200 RPM.

The purpose of a VS pump is so that you can run it slow most of the time. Mine runs at about 1000 PM most of the time and the PSI gauge reads about 3 PSI.

Jim R.

 

[Richard320]

I'd run it full speed to get the baseline pressure, the way us luddites with single-speed pumps do. And pay attention to which valves are where when you take your readings.