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main drain does not work, can I close off?

main drain does not work, can I close off?

Old 11-21-05, 10:02 AM
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Arrow main drain does not work, can I close off?

Hi there,

We recently moved into a new home with a 26 year old pool.

When we had a new pump installed, we were told that the main drain did not work and if we wanted to let water out we could use the back wash.

We have a leak, and we've ruled out the skimmer and light fixture, and believe it's from the main drain.

Can we seal off the underground pipe that it is the main drain? We're wondering that if we do, and water gets trapped, if it would eventually release gas/chemicals underground that could damage the pool later on.

Any info would be appreciated, thank you! :0)
Old 11-29-05, 10:20 AM
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You can plug the main drain with now issues about out gassing chemicals. You don't mention what type of pool you have, concrete, vinyl liner or fiberglass. There are some many leak possibilities in all these pools. If I have more information I can make some recommendations. If you think the main drain line is the problem then I would recommend that you have a pool professional pressure test the line for you. If you look in the yellow pages under leak detection these people can help as well, and perhaps tell you exactly where underground it is leaking.

You can drain your pool without the main drain. The term main drain carries over from the early 1900's when pools did not have filtration and sanitation. What they would do when the water started to get bad was open the drain at the bottom of the pool and drain all the water out then refill it until it got bad again. Boy those were the days. No equipment no chemicals! Even thought we call it a main drain today its main purpose is to complete the circulation of the pool water from the bottom of the pool. If you close this suction line off make sure you direct one of your return jets to point to the bottom of the deep end. This will help the circulation and keep the deep end from becoming cloudy.

To drain the pool you would have to hook up the vacuum hose like you were going to vacuum and then if you have a multiport valve that has a "waste" position use that. Try to avoid backwashing to drain the pool if at all possible. If not you can use backwash but if you have a sand filter you may end up dumping sand (your filter media) out of the filter and may have problems later.

Good Luck,

Guru of Pools
at xxxxxxxxxxxxxx.com

Last edited by Annette; 11-29-05 at 10:24 AM. Reason: advertising personal business websites is PROHIBITED!
Old 11-29-05, 03:26 PM
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if it were a return line (in a pool with 3-4 returns) I'd say, "yeah, close her out"

and yes, you can close off the main drain ... but it may not be worth it though

it comes down to cost of repair vs. inconvenience of not having main drain

first, skimmers "skim" --- they only pull the first 6-12" of water from the surface --- the Main Drain's taking care of the rest --- that's reason enough to repair it

more reasons:

what if the skimmers or their lines began leaking?

you'll have to constantly maintain high water level (which you should do anyways --- but if the water drops below the skimmer, and there's no main drain, the pump will run completely dry -- and burn out

and --- you'll either have to hook up your vacuum (and plug remaining skimmers) or use a trash pump to drain the pool ... "Back wash" is a setting on a valve ... it has nothing to do with operating a pool with a main drain or no main drain ... backwashing is used to clean filters --- don't drain the pool with that anyways --- use the "Waste" setting when you're intentionally draining.

closing off the main drain because of a leak (and while you did rule out skimmers & other lines --- are you positive it is the MD leaking??) is like having your arm amputated because it got broken.... (pardon that really odd analogy, lol) ...

all in all, i'm not the one with the check book --- it's very easy for anybody to say "just fix it" when they're not paying for it--- the cost of the leak repair vs. inconvenience of no main drain is the big question for you ---

good luck!

Last edited by dally69; 11-29-05 at 03:36 PM.
Old 11-29-05, 03:40 PM
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haha, yeah like what guru said --- he beat me to it!!!

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