New Variable speed pump, low speed operation concerns

[missourian]

Yesterday I installed a brand new Hayward MaxFlo VS with the help of my friend, everything went smooth except few minor annoyances with wiring the new pump. I have few questions related to low speed operations;

1. With my old pump(2.4 THP) the DE filter pressure was 21 PSI, but with the new pump, DE filter has a PSI at 11 even at full 3000 RPM, more than 50% drop, is this normal?

2. At 1760 RPM filter pressure stands at 3 PSI, anything less than that, pressure gauge bottoms out (goes all the way to zero), I lowered the RPM all the way down to 1000 and verified the pool return jets are pushing water without any issues and the circulation is good, so my questions is if I run the pump at 1000 RPM with pressure gauge reading zero, is my DE filter effectively doing the filtration?

3. At 1760 RPM my spa return jets not getting any water flow, I see minimal flow at 2200 RPM, I do have a spring type check value installed at the spa return line, I want to know how other VS pump owners with similar set up addressing this issue.

4. The new pump motor was made by "Hanning Elektro-Werke" and it says made in Germany, a quick search in TFP about this manufacturer returns nothing, I assume it is a good one.

5. I would say there is no effective skimming at low speed, I assume this the trade off for running low speed.

 

[JasonLion]

1) Yes.
2) Yes. You need a higher speed to coat the grids with DE. After that you can run at a very low speed and still filter just fine.
3) Run at a higher speed.
4) They are fine. There are many companies making motors that are all fine.
5) Then you should be running at a higher speed. The minimum speed at which the skimmers work is the lowest speed you should ever use.

It is quite possible that pump is too small to properly run your spa jets.

 

[missourian]

Thanks Jason appreciate your response.

 

[missourian]

sorry if this is a stupid question, is there a difference between 3HP pump operating at 1000 RPM and 1.5 HP pump operating at 1000 RPM? Especially the impact on pressure and volume of water movement.

 

[JasonLion]

Yes, a noticeable difference. To get the same flow you would get from a 3 HP pump at 1000 RPM you will need to run at a speed noticeably higher than 1000 RPM.