I just spent the last few hours reading all the 187 postings related to washing machine discharge overflow - but haven't quite found the answer I'm looking for.

Background - 1960's concrete slab So. Calif home.
1-1/2" washing machine discharge line going to a P-trap about 18" below it (if I remember correctly when I replaced the drywall) to a 1-1/2" vertical pipe that both extends into the attic (and is revented with the kitchen sink somehow) and going into the slab into what I think a 2" cast iron tee. I don't know how the 2" cast iron tee is stepped down to the 1-1/2" pipe, doesn't look like any threaded adapter, more like cement.

This cast iron tee is originally cleanout that now is connected to a 2" NPT male to 2" ABS trap to a wash tub about 5' away from the cleanout.

"Normally", the washing machine pumps out its contents and the water rises in the wash tub about 1". In the past eventually some blockage will make the water rise higher and higher - maybe 4", and eventually the drain will be blocked. Luckily the wash tub capacity is more than the washer and we haven't had an overflow.

If I remove the laundry tub drain at the 2" cast iron cleanout and snake it there things go back to 'normal' - which is again 1" of water in the wash tub at the end of the pump out.

The 2" cast iron tee goes into the slab and the kitchen sink too is tied into that line somehow since when it is completely blocked, the kitchen sink too is backed up. From what I can tell the path is kitchen sink - washing machine/laundry tub, a Y where the bathrooms on the other end of the house feed into, main cleanout, city sewer. Whenever there is a backup, the main line cleanout is clear as are the toilets.

Questions:
- I know I have a recurring blockage - each time (2X in the past 4 years) I've rented a power snake that is 1/2" x 50', and installed only 1/2 of one of the cutters on the end - seems this is the largest end I can put on and still get it to go into the 2" cast iron cleanout. I don't ever get it completely cleaned out since my wash tub has always backed up a little bit.

- How can I open up the obstruction even BIGGER? With one half of a cutter installed I'm guessing I can punch through maybe a 1" diameter hole. Pulling back the snake I don't see anything wrapped on it.

- The cast iron tee and I'm guessing pipe in the ground is nice and rusty on the inside - could this be constricting the diameter and how do you ream that out? Is a 1/2" snake too big for 2" cast iron pipe?

- Any chance my drain pipe and vent are undersized? I am open to the idea of replacing the washer drain pipe and vent with 2" PVC, but will this cure my problem? And how do I get the 1-1/2" copper pipe out of the 2" cast iron tee?

- I see postings about raising the stand pipe and needing 36" of standpipe. What are the symptoms of an insufficient standpipe height?

- lastly, do vents serve any purpose other than breaking a siphon from emptying traps? Reason I ask is that occasionally when the laundry tub is draining slowly, I'll hear the drain 'burp' like it is relieving an air bubble. Is this a clue?

TIA
Dave

Good morning Dave.

(1) - How can I open up the obstruction even BIGGER? With one half of a cutter installed I'm guessing I can punch through maybe a 1" diameter hole. Pulling back the snake I don't see anything wrapped on it.

We use a Ridgid K-50 sewer machine with about a 3/8ths cable with a auger tip on 2" lines. Since the washer clogs are fiber mixed with grease we always pull something back on the tip. If you have a kitchen sink with a disposal on the same line the odds of a clog increase dramatically. Since the cable flops around inside the pipe it pretty much scours the pipe walls. Sometimes with stubborn clogs we pour boiling water down the drain while running the cable. The boiling water melts the grease and flushed out the line.

(2)"- Any chance my drain pipe and vent are undersized? I am open to the idea of replacing the washer drain pipe and vent with 2" PVC, but will this cure my problem?"
With todays more powerful washer pumps all our washer drainage, trap and standpipe are 2" Even if you increased the standpipe to 2", ( the vent can be 1 1/2") you would still be choked down to 1 1/2" at the trap. I don't think your problem would be solved by just increasing the diameter of the standpipe.

(3) "How do I get the 1-1/2" copper pipe out of the 2" cast iron tee?"
A 2" X 1/2" Threaded Midland Bushing converts from cast iron to copper. it simply unscrews.

(4) "I see postings about raising the stand pipe and needing 36" of standpipe. What are the symptoms of an insufficient standpipe height?"
If the standpipe's too short the discharge can hit the bend of the trap and bounce back and overflow. The higher the stand pipe the less chance of that happening. Also a larger diameter standpipe holds more volume. Add that to a taller one and the discharge has a much better chance of draininhg away.

(5)" do vents serve any purpose other than breaking a siphon from emptying traps? Reason I ask is that occasionally when the laundry tub is draining slowly, I'll hear the drain 'burp' like it is relieving an air bubble. Is this a clue?"
Vents allow the system to breath and that's their only purpose.
Yes, "Burps/bubbles and Gurgles certainly are clues. Let me explain.
Bubbles" and "Gurgles". They are both indicters that something's going on in your drainage system.
A "bubble" indicates a clogged line while a "gurgle" indicates a blocked vent. Let me explain. When you flush the discharge drains down the pipe until it hits a partial clog. Then it rebounds back sending a "bubble" of air ahead of it. When you flush a toilet or drain a bathtub a suction is created by the water rushing down the pipe. This suction is relieved by a open pipe that runs to the outside called a vent. When a vent's stopped up the suction has to relieve itself somewhere, in this case your toilet. The noise you hear is the air being pulled through the trap by suction, (gurgle).
Hope I've helped a bit. Happy Labor Day! Tom

Thank you Tom!

Regarding increasing just the standpipe to 2", I was actually thinking of replacing the whole section with 2" PVC - standpipe, p-trap, vent, etc. I want to fix this and make it 'better'. At least I hope to extend the time between needing to snake it out.

So, a 1-1/2" vent can be used on 2" drain? That would be great if I didn't need to do any attic work!

One last question - where is the main cleanout located relative to the sewer line leaving the house? Reason I ask is that I've put all 50' of snake down this line before, yet I never see it flopping around in the main cleanout when I peer down into it. The main cleanout is only ~30' away from the laundry cleanout. I suppose the snake could be going the wrong way in the Y where the back bathrooms tie in, but I thought these Y's were directional?

Thanks again!
Dave

Anyone?

Quote:

---

Originally Posted by Probedude

Thank you Tom!
So, a 1-1/2" vent can be used on 2" drain? That would be great if I didn't need to do any attic work!

One last question - where is the main cleanout located relative to the sewer line leaving the house? Reason I ask is that I've put all 50' of snake down this line before, yet I never see it flopping around in the main cleanout when I peer down into it. The main cleanout is only ~30' away from the laundry cleanout. I suppose the snake could be going the wrong way in the Y where the back bathrooms tie in, but I thought these Y's were directional?

Thanks again!
Dave

---

Hi Dave,

"where is the main cleanout located relative to the sewer line leaving the house?"
We are required by code to install a cleanout, where the sewer leaves the house, not over 18" from the house foundation and bring it up to grade so it may be seen. Unfortunately, over time, this might be overgrown or buried. Just poke a sharp rod in the ground until you hit it. That's what we have to do.

"I thought these Y's were directional?"
They are. DO NOTsnake against he flow.
Regards, Tom