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Diver64
Backup from washing machine into kitchen sink

OK, here it go's...I bought a 75yr old house and everything is in need of repair. Here is one of the things that has me stumped and I can not find a thread that explains it out for me.

The kitchen has a washing machine in it which was added sometime and a hole cut in the floor for the drain. The drain line runs down to the crawlspace and is a 1.5 inch black water line, not rigid and ties into the drain for the gray water field downstream from the kitchen sink line using a rigid Tee connection. These are the only 2 lines on this. The main line out of the house looks to be 4 inch PVC. The line from the washer to the Tee is about 20ft long and its also 15ft from the tee to the kitchen sink which looks like a 3in rigid line. There is no venting on this line for either the kitchen sink or the washer inside or outside the house or on the field. With the original washer when it ran air would bubble out of the kitchen sink. No water backup and the washer seemed to work fine just air and splashes. I surmised that the field was not large enough so first replaced the washer with a new HE machine that used less water. No dice. I then dug up by hand the gray field and replaced the single pipe there with 2 pipes on sand and gravel. I also put a surge barrel before the small field figuring with only a washer and a sink it would be big enough and would fix the problem but it still bubbled up into the sink. I then put a stodder vent on both the sink (under it) and behind the washer but it still backed up. I then removed the rigid connection where the washer went into the main line below the sink line and put a flexible tee there to see what would happen leaving the top open and water comes out of it where the washer comes into one side and the sink still bubbles but not quite as bad. Now what?

Anyone have a solution to this?

Is the field maybe still not large enough and I have to put a second surge barrel in or make the field itself bigger since the soil is only a few feet deep and then solid clay?

Vent down stream of both sink and washer maybe cutting into the main line outside the house and putting it there?

Change the washing machine line from 1.5in to 2 or 3in line?

Totally stumped here and all of the help I can get would be appreciated. Thanks

JLMCDANIEL
Re: Backup from washing machine into kitchen sink

Newer washing machines require a 2" or larger drain.

Jack

Diver64
Re: Backup from washing machine into kitchen sink
JLMCDANIEL wrote:

Newer washing machines require a 2" or larger drain.

Jack

What do you mean by "newer"? The original machine was a regular old washing machine and it still threw water into the kitchen sink. Thanks

johnjh2o
Re: Backup from washing machine into kitchen sink

If all you have on the two lines are Studer vents that is more then likely your problem. You need to have a least one vent that extends to the atmosphere. Studer vents only allow air to enter the system the don't allow any to escape. When the washer drains it is causing a back pressure in the waste line because there is no where for the displaced air in the line to escape.

Diver64
Re: Backup from washing machine into kitchen sink
johnjh2o wrote:

If all you have on the two lines are Studer vents that is more then likely your problem. You need to have a least one vent that extends to the atmosphere. Studer vents only allow air to enter the system the don't allow any to escape. When the washer drains it is causing a back pressure in the waste line because there is no where for the displaced air in the line to escape.

ok! Does this vent need to be downstream from both pipes?

1) I'll replace the 1.5 inch pipe with rigid 2 in or, since I'm changing the pipe should I go larger on the washing machine line?
2) I'll put a vent in downstream outside before the surge barrel. One that looks like the vents at dumps for methane I guess. How big does the vent pipe have to be? 2in, 3in....? and how tall. A few feet with an elbow for rain be big enough since I have no smell from the washer or sink when it backs up.

Thanks for the help.

dj1
Re: Backup from washing machine into kitchen sink

1. 2" is enough.
2. For the vent use 1-1/2" or 2". Has to extend about 1 ft above the house. No need to protect it from the rain.

Diver64
Re: Backup from washing machine into kitchen sink
dj1 wrote:

1. 2" is enough.
2. For the vent use 1-1/2" or 2". Has to extend about 1 ft above the house. No need to protect it from the rain.

Why above the house? This old house has no plumbing on the second floor only the ground floor.

dj1
Re: Backup from washing machine into kitchen sink
Diver64 wrote:

Why above the house? This old house has no plumbing on the second floor only the ground floor.

I don't think you are following. Vents should rise up to the exterior, preferably through the roof. They should extend about 12"-15" above the roof.

keith3267
Re: Backup from washing machine into kitchen sink

First, I think you will find a major clog in the main drain line. Second, I don't think you need to vent through the roof for this, but you do need a vent to atmosphere somewhere along the line.

Diver64
Re: Backup from washing machine into kitchen sink
dj1 wrote:

I don't think you are following. Vents should rise up to the exterior, preferably through the roof. They should extend about 12"-15" above the roof.

No, I am following you. I'm just wondering the reasoning behind extending the vent pipe over the top of the roof. I have no way to run this pipe inside so it will have to be outside of the building.

I did pull the main pipe apart when I put in the new gray water field and tank and it was clean.

BTW: I went and read the installation instructions for the HE Maytag Cabrio I put in and it does say 2 in line right there in black and white. I guess I never thought to check the drain line size under the house assuming it was bigger.

Thanks for the help.

Mastercarpentry
Re: Backup from washing machine into kitchen sink

The venting occurs above the roof for two reasons. One is odor- above the roof it dissipates quickly and is rarely an issue. Second and most importantly is that sewer gasses can be poisonous and contain nasties which can lead to another obituary column.

Many old houses here have the entire drain stack (including the vent) ran on the outside of the house. While not pretty, it works. You really need to vent above the house somehow. So long as it's within 40ft laterally of the fixture being vented and there is an upward pitch toward the vent, you can locate it anywhere in a convenient wall where repairs are easier, such as in an exterior closet wall. At the top plate line it can turn so that it either clears a couple feet above the eaves or so that you can run it through the roof. It's not that tough to do and one vent can usually serve all fixtures when it's done properly.

Studor vents are to be used only where proper venting is practical impossibility such as with a sink in an island. They are not to be used as a stand-in for a proper vent which is where this problem comes from. Get out the drill and holesaw and run a proper vent before someone gets deathly sick.

Phil

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