Bottom drain

[Roddapool]

How do you blow out the bottom drain in the deep end.

[Poconos]

I have to admit I haven't paid attention to any posts about this issue. I'm not qualified to comment on this at all so when I see some info I'll add it to my sticky. I know there was a lot on the old forum, before the crash. You may also try the search function. Don't have time right now.
Al

[ChuckD]

How do you blow out the bottom drain in the deep end.

Hey Roddapool,
Fellow Long Islander here (but my pool's Upstate).
Last year was my first time closing my 22K IG. It's at 1000' elevation outside Albany, so deep freeze is to be expected. I lowered the water level ~18", forced air into the pump end of the maindrain line with the leaf blower part of my shopvac and quickly capped with a rubber stopper and duct tape. I'm pretty sure I wasn't 100% effective getting the water out but consider that the level of the water in the maindrain line will only rise as high as the surface of the pool water, just like a water level. So for me that puts it 18"+ below the ground surface.

i guess it could happen that the ground would freeze that deep (that"s why they specify foundation footings to be 52" deep in our area) but with the inevitable air cushion in the pipe, I don't worry too much about bursting.

HTH.

Chuck

[Poconos]

A number of years ago I remember reading an online paper on some Alaskan site about why pipes burst. As I recall it is anytime you confine the water and then it freezes and expands. Simple Physics. The confinement can be simply two sections of pipe freezing and then the water in the middle freezes and the pipe bursts. Such as a water pipe in a crawl space. Your logic sounds right in that with a pipe down to a main drain, even with water up to the pool waterline and therefore above the frost line, the water would start freezing closest to the surface and work its way deeper but the bottom end of the pipe is always open to the pool. Therefore no ice plug and no burst. I guess where one could get into trouble is if there is a horizontal run above the frost depth. Anyone doubt this just stick a vertical piece of PVC in a pool that will freeze and see what happens after the Winter. It shouldn't crack. This thread made me think a little about the main drain issue. More comments welcome so I can include info in the sticky about closing IG pools.
Al

[ChuckD]

And that would describe my situation: 35' from the pump to the closest point on the pool (in my case, the skimmer). Then another 8' horizontal to the drain.

That's why I go to the trouble at all to try to blow it out, to get water out of that horizontal run. I'd like to know the density of this RV antifreeze I hear about. If poured into water, will it sink or float? Or just mix?

Maybe I can get Letterman to try this for me??

[ChristopherS64]

I have always blown air into multiport valve with it opened to main drain. After seeing steady stream of bubbles coming from main drain I assume line is void of water and close valve thus trapping air into line.

[JonnyG]

My pool company uses a rubber stopper with a tire air fitting on it. Places the rubber stopper into the pipe on the filter end and then uses compressed air to fill the line until air bubble come out of the main drain. Seems like this is standard procedure for them.

John

[tphaggerty]

Ha! That is what I was thinking of doing (except using one side of a union with a PVC capped glued on with a tire valve put in). My PB just filled the line with antifreeze last year, that seemed to work as well.

[MarkC]

Pool stores carry that type of stopper with the tire valve stem on them.

[tphaggerty]

Pool stores carry that type of stopper with the tire valve stem on them.

I didn't know that. I'll have to check it out, lots easier than building my own. Thanks.