Waste setting causes pump to "un-prime"

[Anaya]

Hi all, this is my first post on this forum, but I have read a lot of posts and they've helped me a lot, so I am looking forward to getting help figuring out what I am doing wrong.

Last week I added a flocculant to my pool. I turned off the pump and let it all settle. Then I went to vacuum it. I have a polaris so I seldom vacuum the pool, but I do know how - or so I thought. Anyway, I vacuumed to waste and all was fine. The next day more of the flocculant had settled and I went to vacuum-to-waste again. This time, when I turned he pump on, the water in the pump immediately drained. I tried to re-prime the pump and it took about 6 times before I could get it. (My hose flow isn't very strong, so I couldn't just leave the hose in the basket and have it continuously fill.) After I primed it I let it run on filter for a day, turned it back off, let the flocculant settle again, and then yesterday tried to vacuum-to-waste again. The same thing happened. The second I turned it on, the water in the pump basket immediately drained. I haven't had time to try and re-prime it.

FYI, the waste function runs the water out of a backwash hose, not hard-piped.

My question is this, what am I doing wrong? These are the steps I am following:

1) turn pump off.
2) fasten hose and pole to vacuum, fill hose with water by dunking it in the pool.
3) connect hose to the skimmer
4) move dial on the Hayward to "waste"
5) turn pump on
6) water instantly drains out of pump basket and no suction.

MY THANKS TO ALL RESPONDING.

[Anaya]

Extra note: originally when it was difficult to prime the pump I thought it was because I had let the water sink too low as I was vacuuming and some air was sucked in. But last night when I tried to prime it, the vacuuming had not been able to be done, so that could not have been the case.

[Teapot]

You have an air leak somewhere. Are you completely filling the pipe with water before you connect and turn on the pump? If not you'll draw air and loose prime.
Easiest way to quickly fill the hose is put it in front of the return jet and it will fill quickly. Don't loose that water but connect up and vacuum

[Anaya]

Hi Teapot, and thank you. When you say "completely filling the pipe with water before connecting and turning on the pump" I am not sure what you mean. If the pump is primed, and the filter function is running smoothly, doesn't that mean all the pipes are filled with water?
(thanks for the tip about filling the vacuum hose!)

[Teapot]

I meant the vacuum hose which you correctly understood, sorry I replied in rush.

[Anaya]

So, any thoughts on why vacuuming to waste would cause the pump to drain?

[Teapot]

It's not vacuuming to waste that's the issue it's drawing in air through the vacuum hose.

[Anaya]

So you're saying I might not have all the air out of the hose, and that is causing the problem. OK, will try again! Thanks for clarifying - I'll let you know if it works.

[Teapot]

You could also have a leaky joint somewhere, how is the vacuum hose attached to the skimmer or do you have a dedicated vacuum outlet?

[Anaya]

It could DEFINITELY be that. I have a pool guy coming out Friday to look for leaks and figure it out. However, based on your advice about air in the vacuum hose, I did a better job of filling it with water, primed the pump using giant buckets of water since my garden hose has insufficient flow to keep the pump basket filled, and WAS able to vacuum to waste. Since I had to do it after work I sustained a million mosquito bites, but I did it. I'm sure more of the flocculant will have settled by this evening, so I am going to try again and see if I have a problem or if it continues to work properly. Thanks for all your help so far.

[Anaya]

I just realized your location is UK. I spent a lot of time there around '98-'01. I don't remember ever seeing a pool! I love England so much; I still miss it after all these years.

[Teapot]

Thank you, most of my pool work was in France, now back in the UK I Google earth around where I live and there are quite a number right on my doorstep.
Where were you in the UK

[Anaya]

I was dating a crazy hippie in Glastonbury! We had a house there. Where in the UK are you? I will definitely Google Earth the area. Do you speak French?

[Teapot]

I am in South London near Bromley. Speak some French but definitely better at pools!

[Anaya]

I'll have to go look at Bromley.
Actually, through the magic of the internet we could look at each other's pools! Want to see mine?