Draining through the Pump?

[JakHammer]

I need to exchange some water in my in-ground, plaster pool and I'm wondering if I can just use the pool pump to take water out?
I have two intake pipes with a "both-or-either" valve and there is a regular faucet bib on the pipe between the pump and the filter.
Assuming that one intake pipe is for the skimmer and vacuum and the other for the drains, couldn't I just hook a hose to the faucet, shut out the skimmer side, and pump the pool down to where I need it to be?
I know it would be slower than getting a submersible with a 2" hose, but I'm in no great hurry...
I'm in AZ so no worries about water tables or floating the pool, and I don't plan to have the water level down for long.
I just don't want to screw anything up with the pump.
Any thoughts?
JaK

 

[JohnT]

At some point, the water may get low enough that the pump can no longer lift water out of the pool, so you'll need to keep an eye on it, but it won't hurt the pump unless you let it run with no water moving through it for a while.

 

[JakHammer]

Wow. This would be reallllly slow...
When I have both intakes open the water flow out of the hose is pretty strong, but when I go to the drains and vac only - cutting out the skimmer - water pressure goes down dramatically. Also get lots of turbulence and air in the strainer bowl at the front of the pump.
Guess I need to go rent a pump. So much for shortcuts.
BTW: Note to self: Always shut off the auto-fill valve before attempting to drain the pool.

 

[JohnT]

If you have a vacuum hose, you can put it in the skimmer with the vacuum on the bottom in the deep end so you can leave both open.

You could also plumb a T and a valve into your return line or open a union and connect a pipe to it to get rid of water instead of sending it to the pool.

 

[CUTiger78]

If you're really in no hurry, you could siphon the water out with a garden hose. That's what I do in the winter, when the water level gets too high.

 

[jblizzle]

Are you sure the suction lines are skimmer&vac in one pipe and floor in the other?

I would have assumed that one was the Vac and the other was the skimmer/floor with a diverter in the skimmer to pull from the floor.

With the skimmer closed, you may be only pulling from the Vac line.

 

[JakHammer]

That could be.
All I know for sure is that when I turn the valve one way the skimmer shuts down and the vac goes into high gear, and when I turn the valve the other way the vac stands still and the skimmer sucks hard.
I know nothing about pool plumbing and can only guess about the drain without throwing a dye-pack or something to see what the water is doing down there.
It surprises me how dramatically the flow is reduced when I'm running on just one side or the other though.
Apparently the pipe between the valve and the pump is too short resulting in serious cavitation when only one of the inlets is engaged.
I rented a submersible for 40 bucks and the pool is over halfway drained now.
Next comes the fun of scrubbing the walls!
Jak

 

[jblizzle]

If you care to figure your plumbing out, what do you see under the skimmer basket? There should be a float/diverter that you can pull out and then I am guessing you will see 2 pipes. One goes to the floor drains and one to the pump. The diverter should have a slide on it to adjust how much is sucked from the bottom and how much from the skimmer.
Either the space ship:
images/ve/lovingHDTV-SkimmerDiverter.jpg
Or the Twinkie:
images/ve/joenj-SkimmerDrainDiverter.jpg

 

[JakHammer]

Ah ha!
That's where the flying saucer on the floor of the pump room is supposed to be.
Looking down the skimmer I see two pipes; one full of water, the other empty.
There appears to be some sort of putty around the top of one of them like something broke and someone tried to fix it with caulk or something. I haven't investigated yet. I'll bet they broke the flying saucer and tried to glue it back on.
Jak

 

[jblizzle]

The saucer should just sit on an o-ring in the skimmer under the basket.

BUT, you should see 2 open pipes. It almost sounds like they either broke something in the other pipe or they tried to close the floor drain or my theory is completely wrong and the floor is not plumbed into the skimmer (although it could be just tied to the skimmer pipe underground)

Post up a pic of what you see.