Too much suction !!

[karenkr]

Hope I am posting in the right place--
Have an IG pool. have been having problems with algae so have been shocking and vacuming a lot. Problem is now I have too much suction and the vacum wont move. I have to pick it up to move to another spot. Started about 2 wks ago--before that no problem to vacum. For some reason it just wont roll. Any suggestions anyone????

[tenax]

you say it won't roll..is this an auto vac? does it have a regulator attached to the hose that you can control the suction with? i've had that problem with both an autovac and manual. especially with the manual as it had no regulator. in my case, i've got a main drain return and skimmer return so i can simply open the main drain a bit to reduce the suction. not as convenient as a regulator on the hose. i have been considering installing a valve that allows some air to get into the vacuum line going to my skimmer (as is the case on the auto vac line) and that would work great.

[tenax]

ps- you said it didn't happen..now it is..i'm guessing that your filter likely needs cleaning. i know with mine that when my filter is dirty, it goes from a standard 10 lb per square inch clean to 15 when dirty, which in turn creates more water pressure in the system overall, leading to stronger suction.

[JohnT]

Hope I am posting in the right place--
Have an IG pool. have been having problems with algae so have been shocking and vacuming a lot. Problem is now I have too much suction and the vacum wont move. I have to pick it up to move to another spot. Started about 2 wks ago--before that no problem to vacum. For some reason it just wont roll. Any suggestions anyone????

Check the brushes for wear (assuming it has brushes). Once they get down so far, the head will start to stick to the bottom.

[duraleigh]

Karen,

I doubt it's too much suction. Your flow thru the system would have to had inexplicably increased for the suction to go up.

Actually, if it was too much suction, that is easy to fix by simply restricting one of the ball valves on the pressure side of the pump. Your filter pressure will go up, and the flow thru the system will decrease resulting in less suction at the vac head.

[tenax]

duraleigh, i'm no expert, but can only go by experience that when my filter pressures rises, my suction increases, rather than decreases. that is factual experience. i can definitely tell the suction has increased?

[cwstnsko]

That seem counter-intuitive. It'd be like saying that your vacuum cleaner has more suction with a dirty bag than with a clean one. To have more suction, you need higher flow rate. Dirty filters cause a lower flow rate and should result in less suction

[mas985]

There is only one condition where this can be true and that is with a 2 speed pump. Going from low to high speed, you are effectively changing the HP of the pump so you will see both a rise in PSI as well as suction.

Assuming the same pump and speed, and the PSI rise is due to a dirty filter, solar or other return restriction, higher filter pressure = more head loss which means less GPM. Less GPM = less suction. This what hydraulic theory dictates and what I have confirmed through measurements.

If you had a suction guage on your pump, you would see it drop with higher filter PSI. However, just the opposite happens when the PSI drops so perhaps this is what you are experiencing.