Simple vacuum, pump not fully priming

Wildcat · Feb 16, 2014

I have a pool with pop ups and with occasional manual skimming and brushing I never needed a vacuum. But this year has been drier than normal and windy so I am getting leaves. Bought a simple hose and vac to attach to my pole. Works ok, I am hooking it to the suction side of my skimmer as I have no other way to connect with my piping setup. I have an Ecostar VSP which fully primes at most rpms with only a few tiny bubbles at 1000 RPM.

But when I use the vac it only fills about 3/4 way with water with a lot of turbulence. Seems not to matter if I run at 1500 RPM or 2500 RPM.
Is this normal? I try and prefill the hose with water but that isn't easy to do, or I don't know the trick. Is that the cause of this?
Will it hurt my pump if I vacuum for only a few minutes every week?

mas985 · Feb 16, 2014

The pump should already be primed before using the vacuum. You should never try to prime a pump with a vacuum attached. Also, the pump should not lose prime if turned off.

If the pump basket is filling with air after you attach the vacuum, then you have an air leak somewhere. Probably the pump lid gasket.

Wildcat · Feb 16, 2014

mas985 said:
The pump should already be primed before using the vacuum. You should never try to prime a pump with a vacuum attached. Also, the pump should not lose prime if turned off.

If the pump basket is filling with air after you attach the vacuum, then you have an air leak somewhere. Probably the pump lid gasket.

No indication of an air leak under any other circumstance. I presented it wrong, the pump is primed, but when I attach the vacuum it gets a void in the basket. Maybe I should have the pump running before attaching the vac so there is continuous flow of water?

Richard320 · Feb 16, 2014

I hook mine up while it's running, and you can really hear the difference in pitch, and I see a lot of turbulence in the strainer basket, but it's not air, it's actually a vacuum. The pump is starving, since I use the hose straight into the skimmer. When I'm done, everything immediately goes back to normal. No air comes out the bleed, therefore, no air got in.

If you fill the hose with water before attaching it you shouldn't draw any air. You'll know if you're sucking air because air bubbles will come out the returns, or the air bleed (if equipped) will hiss when it's opened.

Wildcat · Feb 16, 2014

Thanks, I do see a lot of turbulence, as you say. If one fills the hose with water first will that reduce the turbulence or is it inevitable?

mas985 · Feb 16, 2014

Yes, you should fill the vac hose with water so the pump does not lose prime.

Wildcat · Feb 16, 2014

Stupid question, how do you fill the hose with water, submerge it or with a hose?

zea3 · Feb 16, 2014

There are a couple of ways to fill the hose with water. The best is to position yourself near a return and connect the hose to the vacuum head, lower it into the pool, then hold the free end of the hose against the return so the air is forced out and the hose fills with water. Cap off the free end with your hand while submerged and connect the hose to the skimmer.

Otherwise connect the hose to the vacuum head, lower it into the pool, then submerge the entire length of hose until no more bubbles come out. Cap off the free end of the hose with your hand while submerged and connect the hose to the skimmer. You may need an extra pair of hands to submerge the entire hose at once. Using a garden hose to fill the vacuum hose with water will not work.

Richard320 · Feb 17, 2014

Wildcat said:
Stupid question, how do you fill the hose with water, submerge it or with a hose?

I connect the hose to the vacuum and lower it into the pool, with the hose on the deck, then slowly feed the hose in holding a length at a time vertical so any air in the hose gets pushed up and out the open end. I can usually keep it underwater as I shove it through the skimmer opening and down into the suction port.