How to blow out main drain attached to skimmer basket

[bostonpool]

Hi Folks:

My 40 year old gunite poll will be closed this week. I've been thinking about attempting to do this myself. Despite my pool's size, I've got a pretty simple plumbing layout. I've got 2 return jets from the filter (no valve), and only 1 skimmer basket. The main drain at the bottom of my 8' deep end is connected to the bottom of my skimmer basket and flow is directed via a float valve.

I'm pretty sure blowing out the return jets and skimmer basket should be easy using a shop vac, particularly once I drain the pool down to below the return jets.

But I have more reservation about the floor drain. Since there is no valve, I'm very concerned about how to do this properly. I believe typically my pool guys use a ton of compressed air to blow out the main drain line. Then, once the compressor is removed they "quickly" put in one of the stoppers into the port at the bottom of the skimmer and tighten quickly.

My concern is, this seems very error prone. What happens if I can't get the plug in before water has refilled the line? How can I tell if it was done properly?

Hmmm....
Suggestions?

 

[cowboycasey]

that is exactly what I have heard that people/companies do... once the air is flowing from the main drain you have seconds to get a plug in there to air block the water from coming back into the pipe... there is no way to know how much is blocked in what time, I imagine you have about 3 to 5 seconds... there are thousands of pounds of water in your pool, 282,000 pounds/ 141 tons for your pool.. that is a lot of weight pushing down on that pipe..

You may try it a couple times and the first time to see exactly how long till you see water come back up the pipe... if it takes 8 seconds then you have 4..

 

[trivetman]

Give it a couple practice runs. If you successfully trapped air in the pipe you’ll feel it being pushed out when you release the plug.

also keep in mind that near ground level is where the freeze concern is. The part of the pipe underneath the pool should be pretty well insulated from freezing temps ( i think!) like the water pipe coming into your house. So as long as you trap some air, should be ok I think. In any case, you’re doing exactly the same thing that someone you’re hiring would do. You just don’t have anyone to scream at if it goes wrong...except yourself

good luck!

 

[1Sammy]

You will require a lot of air volume to push that water down. Then you will require the speed of Flash Gordon to get the air line and fitting out of the way and get the plug in far enough to be air ( under pressure) proof. Use 3 to 4 feet of foam rope 3/4 -1" and poke it down there, then screw in the plug. Also no need to drain away all your water down past the returns. Plug them when you get a good flow of air coming out under water.