Stationary tubs drain mystery

I have the concrete stationary tubs, one big tub with a petition in the middle making two tubs. In the back right and left hand corners of the two tubs are the drains. These drains immediately go in one inch and one half pipe with a trap. The wash machine pumps the waste into the left tub. As it drains into the main drain, some of the waste to about a depth on one to two inches comes up into the right tub. However, if I fill up the right tub with water, it will drain without any of the drain water coming up into the left tub. And no, I don't want to drain the wash machine into the right tub. What's going on?
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TOM KAN PA wrote:

Your description of the plumbing is a little vague, I take it that there is only ONE trap, and a tee merges the two drain's pipes into that trap.
Since you didn't mention this, any chance the twin tubs aren't on the level, and the right tub's bottom is lower than the left one's?
Maybe the drain from the right tube is restricted a bit before it reaches the trap, so water going through it flows slowly enough that it can all get through the drag/restriction of the trap without any backing up into the left tub.
Try seeing how long it takes a full bucket of water dumped in turn into each side to drain out completely. If the left tub empties faster, even with some backup into the right tub, then my restriction suggestion is likely the cause.
Let us know what you find,
Jeff
--
Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"As long as there are final exams, there will be prayer in public
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<< Your description of the plumbing is a little vague, I take it that there is only ONE trap, and a tee merges the two drain's pipes into that trap. >> I guess you could call it a tee. The two drains are about six inche apart. The water goes into each, to an elbow immediately beneath the exits. And then there's a couple of inches to a tee which goes into the common drain. This drain set-up from the tugs is a complete unit made for this application. It probably came with the purchase of the tub(s). It is not a home made jerry rigged device. The tubs aren't perfectly level, but we're not talking really out of level. Just a CH, a red CH to be exact.
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is
The
application.
level.
All that means is that your P-trap is doing it's job. Going out the other drain hole is an easier route for the air-water mix from washer hose to take, than to overpower the standing water column in the trap. What happens when you fill up left side with standing water (not swirling drain hose water), and then pull the plug? Does it still come up right drain?
Damn, now you got me curious. I get same phenomena in the 2-hole sink in the break room at work. Now I'm gonna have to experiment.
aem sends...
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<< Subject: Re: Stationary tubs drain mystery From: "ameijers" snipped-for-privacy@worldnet.att.net >> << What happens when you fill up left side with standing water (not swirling drain hose water), and then pull the plug? Does it still come up right drain? >> ____Reply Separator_____ Yes!
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