Re: Wash Machine Discharge
Posted by More on December 27, 2001 at 20:41:58:
In response to Re: Wash Machine Discharge
The Washing machine discharges a pressurized waste into a gravity drain sanitation system. The pressurized waste requires no vent, the gravity system does. The "in the wall" standtube is not likely a 2 inch diameter, but more likely an inch and a half. The washing machine hose is likely a three quarter inside diameter with one inch outside diameter. If you jamb that one inch into a 1 1/2 inch plastic line, it will create a venturi effect that will be caused by the pressure waste falling into the gravity line, which will be starved for venting capacity. In these cases, the vacuum formed tries to vent in the closet fixture, and sucks the water out of a trap (trying to equalize ambient air pressure) which in turn causes an unsanitary admission of sewer gas and odor into the house from an unrelated fixture. The 2 inch drain size allows the washing machine hose to rest inside while providing area at the annulus to allow venting. But there is a need to protect this washing machine drain from allowing sewer gasses back into the room, which normally requires opening up the wall, and installing an adequate trap. Some manufacturers supply an aftermarket trap protected washing machine drain that will protect your family.


In remodeling laundry room I wanted to switch from discharging into a laundry tub to an in the wall "stand tube". I think I remember seeing that basically that is just a 2" pipe with atleast 24" above its trap. Is this right? Anything else I need to know?

: Thanks, Kent

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