Question on Manual Vacuuming

[jp99]

New to pools. Having a problem in priming vac hose; slowly sinking the hose (attached to vac head) into the water with hose following does not fill the hose; placing the hose end over the water outlet/return does not seem to fill the hose - outlets are not particularly powerful and most return water comes in from the attached spa. New hose with lots of coil torque.

Used spa jets to force water through hose - worked fine but, of course, added air to the lines. Removed as much air as I could via the filter bleed valve but doesn't seem to get it all. Having tried this, the manual vac will work but with air in the system it's not outstanding. Normal filter pressure is 15 lbs and with this clumsy solution filter pressure cycled between 5 and 10 - didn't sound good so I quit early.

Questions:
1 any suggestions on priming the vac hose correctly?
2 when hose prime is good and skimmer connection is good, I assume the filter will run at normal pressure when vacuuming manually - true?

Thank you.

[Poolio]

have you tried isolating suction down to only the skimmer you're using? If you have three-way valves that are plumbed in front of the pump make sure that the other skimmer (if you have more than one) and the main drain are off or at least partially restricted. If you are pulling mostly from one line, the pump should be able to prime itself up again. **If you restrict the suction solely to one line you may get cavitation in the pump (air swirling under the lid accompanied by louder motor).

I'd turn off the drain and partially restrict the other skimmer. "Off" on the valve handle should face the pipe you want to turn off.

[jp99]

Only one skimmer; remove skimmer basket and it shows a suction pipe (rear) and an "inlet" pipe (front, poolside) which is connected to main drain; suction pulls "in" from main drain; no three-way valves in front of pump. So, no way to turn "off" the main drain.

Seems that the air in the vac hose should bleed out when the main filter air vent is opened. When doing that, air did come out followed by water, but cavitation still obvious at the pump and filter pressure fluctuated at 5-10 lbs rather than steady 15 lbs. I ran it that way for about 5 minutes, expecting the air to bleed out and cavitation to stop and filter pressure to get to normal. Do it longer??

[Poolio]

Okay, you probably need a skimmer control plate. This is inserted into the skimmer and has a hole in it and a plug. Like this: http://www.spapartsshop.com/51b1024.aspx

This has a tab that, when rotated in front of the main drain inlet to the skimmer, blocks that port and takes all the suction from the skimmer. You insert the vac hose into the hole in the middle and this should solve the problem by cutting off the main drain.

[jp99]

Poolio - thanks for your patience on this. Perhaps I wasn't clear enough. The vac hose attaches very well to the "suction" pipe in the skimmer - when so attached, there is no draw from the main drain pipe in the area of the "suction" pipe - full pump draw is at the vac hose attached.

The remaining problem (which I think is a problem) is air in the system. Per earlier post, my problem was getting all the air out of the hose. Did this again yesterday but this time I used a separate pole to force the hose down and it seemed to work much better - the hose seemed to fill much better. On attaching the vac hose to the skimmer suction side, the draw was excellent with much less cavitation at the pump - still some though. Bleeding air at the filter helped but not completely. I did get a steady 7 lbs at the filter where normal is 15. It was good enough to vac the pool and it worked nicely.

Question - when you vac, as I am trying to do, what pressure change do you see - if any - at the filter? In my case I saw a drop from a normal 15 lbs to 7 lbs. Do you see a pressure drop when vacuuming?

Thank you.

[czechmate]

When you vacuuming, ALL other returns must be closed. This will create the maximum suction by the pump on the single remaining return line. Since you returning only through single line, the supply to the pump is very low. Therefore, the pumps water supply is low and it can not create much of backpressure. It is starving a bit and may have a higher pitch sound. 7 pps is about right.

[jp99]

czechmate - very helpful - thank you for taking the time to respond and educate.