2 washer machines one drain?

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Jadnashua

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I don't think it would work...if both were draining at the same time, I think you'd get backup in the line. If you could increase the pipe size to 3" where they combine, it should work. the ID of a 2" pipe, say = a factor of 1, a 3" pipe, being the square of the radius = 2.25, or over twice the ID area, so more than twice the capacity of the 2" line. You'd need to properly vent each trap so when one drained, it didn't siphon the other's trap dry.
 

Speede541

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A washer has a DWV fixture unit of 2, and a 2" drain pipe has a capacity of 6. Besides, a washer only has a 1-1/4" drain pipe. Is there a reason why this shouldn't be done?

I've given half a thought to two side-by-side combination washer/dryer units, vs. a separate washer and dryer. No solid plans or research into these machines, but that would be part of the planning.
 

Terry

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Some codes allow two washers on 2". UPC in Washington would be okay with 2".
IPC wants 3" after the vent. IPC wants that for suds control. Though, I've seen 3" that wasn't sloped correctly have issues too.

A washer may pump out with a small line, but once it hits the standpipe and trap, it has to drain by gravity.
 

Sylvan

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NYC has increased the discharge from one washing machine from 2" to 3 "

If you have a 2" waste line and a double sink laundry tub you maybe able to use two machines as each tub maybe able to handle the volume with a controlled flow . The newer machines use a lot less water
 
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