Washing Machine Drain Vent Pipe

A full sized vent is a primary vent where the drain line transitions at some point and becomes the vent pipe that exits the roof.

Washing machine drain vent pipe.

The correct way to drain a washing machine is to install a standpipe. As water goes down a drain air is needed to equalize the pressure in the drain line. Drain pipe not the proper size. The 3 inch pipe would never completely fill with water even if you filled the lavatory sink and pulled the stopper.

Aside from having a clogged standpipe there are a few other reasons why your washing machine drain might overflow and some of the other most common reasons are. It allows air in which prevents the possibility of a vacuum forming that could affect the water draining from your washing machine. It is the end of the trap arm the origin of the vent and the origin of the drain for this fixture. If the drain lines in your home have poor venting as in figure a for example water rushing down the drains will pull water from nearby p traps.

The standard washing machine expels enough water into your drainage system to empty other p traps in nearby toilets and sinks due to a lack of air in the system. The pipe that drains the lavatory sink is 3 inch in diameter because that drain line also acts as a vent for the toilet. This is the purpose of a venting system. The drain in the toilet bowl is basically a p trap.

A laundry standpipe connects a washing machine s drain hose to a home s waste stack. In many an older home this drain pipe is perhaps 4 inches in diameter and stays that size all the way through the roof. This wet venting is permitted by most codes. A sturdy 2 inch pipe will work well as a standpipe.

The top of the standpipe must. Is the fixtures tail piece the vertical section before upstream of the trap. You should also install a vent if your washing machine is more than 4 feet from the vent stack as this will make sure there s ample room for the washing machine to drain properly. A washing machine pipes tail piece must be at least 18 but no more than 30.

If the drain of your washing machine fits tightly into the drain you definitely need a washing machine drain vent. That is a vertical length of pipe that connects to a p trap that in turn connects to the drain. The newer washing machines may use more water and exhaust it faster than the existing washing machine drain pipe was designed for a 1 1 2 to 2 inch pipe installed where a 2 1 2 inch pipe is now needed. The inside diameter of the drain pipe should be a minimum of 1.

Step 3 install an air admittance pipe aap if it is inconvenient or too expensive to install a regular vent pipe. To properly drain your washing machine you ll need to have three components. When the tee is set upright in this fashion we call it a stack vented fixture.