Trouble with main drain

[jspeacock1978]

My wife and I bought a new house last August with a 19,000 in ground pool. Our last home had a 7,000 AGP so I know enough keep the new pool from turning green. A few months ago, I heard a strange noise coming from the pump after a strong storm. It turned out the pump was cavitating and very little water appeared to be moving through the pump's skimmer basket. The pool skimmer was completely full of leaves. I tried to pull the basket out but there was so much suction, I had to turn the pump off first! After I cleaned the basket and turned the pump back on, I began to wonder if the main drain was drawing any water from the pool. Fast forward to a few weeks ago. With warmer weather upon us, I took time to dive into the pool and remove the cover from the main drain. There appear to be a bunch of silt under the cover. I stirred up the silt until the pool began to get cloudy and turned on the pump. The silt didn't react except to fall to the bottom of the pool. I shoved a garden hose into the the pipe off the drain and was able to feed about 12 feet into it. I'm sure it stopped due to a 90 somewhere in the system. I was unable to clear the blockage with the hose on full and there was no improvement when I attached one of those expanding bladders to the hose and tried again. I tried putting the hose into the suction side of the pump and the pool skimmer, but each time, the water came out the other side with no movement at the main drain.

I'm at my wits end over here. There are two ways for water to get out of my pool, the skimmer and the main drain. There is a single pipe that emerges from the ground and goes into the suction side of the main pump. My skimmer has a single hole at the bottom so I know the main drain isn't running through the skimmer. My only guess is that someone connected the skimmer and drain together somewhere between the pool and pump, but I'd rather not dig it up and begin hacking apart the lines looking for the blockage.

How can I find/resolve my blockage issue?

 

[kadavis]

Could you post a picture of the skimmer, and the suction side plumbing at the pump

 

[Jimrahbe]

js,

If you have a single pipe that comes out of the ground into your pump, then your main drain is plumbed into your skimmer. In most cases there are two holes in the skimmer, one to the pump and one from the main drain.

But, this is not always the case. I have a rent house that only has one visible hole in the center of the skimmer. But, at one time there was a plastic door that you could slide over the hole which basically shut off the skimmer and selected the main drain. I don't ever use the main drain, but found that I could put a rubber ball in the hole and then water would be drawn from the main drain.

Thanks,

Jim R.

 

[jspeacock1978]

Here are the pictures requested. The first is the skimmer with the single pipe at the bottom. Sorry, about the picture, but the pump was on and without the basket in the skimmer, there is so much suction, I get the whirlpool. The second is all of the pool plumbing, but it shows the suction side of the main pump fairly clearly.

 

[Jimrahbe]

js,

With only one pipe coming up out of the ground and going directly into your pump, then most likely your main drain is plumbed into the bottom of your skimmer.

Thousands of pools have no operating main drain and they work just fine. So the simplest option is to do nothing about your main drain not working.

But, if you want to see what happens, you can take a tennis ball, or something similar, and place it over the hole in the bottom of your skimmer with the pump running .. One of two things will happen.

1. The pump will immediately run out of water. If so, turn off the pump and remove the ball. Do not let the pump run more than a minute without water.

2. The pump will start pulling water from the main drain. The pump may strain a little and you may get a few bubbles.

If I were to drain my pool I would not use the pool pump as that is not what they were designed to do. I would rent of buy a submersible pump and drop it into the pool's deep end.

Thanks,

Jim R.

 

[kadavis]

I believe that is the old Admiral skimmer, the main drain line is connected to center in the front. There was a diverter used called the vari flo so you could run both top skim and bottom or by turning you could shut off bottom drain. Skimmer Diverter, Pent /American Products Admiral, Vari-Flo - PST Pool Supplies

 

[jspeacock1978]

It turns out that its something similar to that Admiral skimmer. I think the "spoon" is broken off, but the arrow actually points to a 180 degree dial. At the 6 o'clock position the skimmer blocks off the main drain entirely and at 12 o'clock its wide open to the main drain. I've set it at about the 5 o'clock position so it allows for a small amount of suction to be diverted to the main drain for filtration and "deep" water circulation.
Thanks guys!