installing a cleanout port to the main stack (4" cast iron, I think)

[LMHmedchem]

Hello,

I am having some sewer backups again. This has happened a couple of times before and I have been able to fix the issue with Instant Power Main Line Cleaner. This has worked well but it is a pain because you basically have to avoid using water for a day. I have a basement sink that is right next to the stack and connects more or less at the elbow where the stack bends to go out to the street. I put a union in the vent for that sink because it allows me to run a snake right into the main line. I can also pour in the main line cleaner at that point.

This time the cleaner did not work. I will try again but I am also looking at more direct methods. As far as I remember, there was a clean-out just after where the stack goes under the floor. There were several boards in the floor and you lifted them out and there was a clean-out port in the pipe with a bunch of gravel around it. Tonight I took up the carpet because I was going to open the clean-out in preparation for using a power auger tool. I can't find the clean-out anymore. It just isn't there. I must have put concrete over it when I put in the carpet, or else someone else did, I just don't remember.

At any rate, I may need to be able to get into the main pipe to clear the blockage. I could break up the floor and try to find the old clean-out but I am wondering if I can install one in the stack. There is about a 5' straight run of the stack between the last Y fitting and where it goes into the floor. I could cut out a section and install a T with a plug in this section but there are some things I am not sure about.

1. Can I use a rental power auger if I insert it before the elbow in the stack (where it turns to go out to the street)? I know some such tools have a straight section before the auger tip that might not go around a corner.

2. What would I use for a fitting? The current stack is cast iron and I think it's 4". I have seen junctions between cast iron and PVC with rubber sleeves and ring clamps. Is that the kind if thing I would need or is there some other way to transition between cast iron and PVC?

3. I don't have a cracking tool so I suppose I could cut the cast iron with a grinder and cutoff wheel, would that work?

I was able to run drill powered snake all the way out to 25', so what ever is blocking the pipe is not terribly difficult to get through. There was resistance at a couple of points but the drill worked the snake through it with little issue. Nothing came out when I removed the snake.

Does anyone have any information or suggestions?

LMHmedchem

 

[LMHmedchem]

Here is a picture of the main stack where it enters the floor.



The old clean-out used to be in the floor about 3' on this side of the pipe The distance between the floor and the first flange in the pipe is a bit less than 44". The cast iron pipe is 4" OD. The 2" PVC to the left is the plumbing from a double sink. The horizontal 2" PVC at the bottom is the drain from the washing machine. The union in the 2" PVC is the vent for the sink and this is where I can go in with a snake or add the drain cleaner. This 2" PVC enters the stack below the floor somewhere.

I used some more main line cleaner and it seems to have helped some but has not cleared the problem. I can run the snake in further then I could before but I am still hitting an obstruction. If I run the basement sink it will eventually fill with water. The water will go down slowly so some water it getting through. If I flush a toilet enough times to fill the stack then that will end up in the basement sink as well.

Based on my measurements with the snake, the obstruction is just on the other side of the outside wall, which puts it under the front porch. What is odd is that the snake hits something where I cannot push the snake through by hand. If I apply a little power with the drill, the snake goes right forward. I have done this with the sink full of water and punching through does not seem to affect the rate of drain. I have gone forward and backward with the snake. I have powered the snake in some and then pulled it back by hand. I have powered the snake in some distance and then ran it backwards while pulling it out. None of this seems to make any difference, which doesn't make sense. How can the snake go through but the drain not clear?

At any rate, I can brace the stack and put a clean-out in the ~44" vertical section of cast iron pipe using a 4" DWV PVC "Y" fitting, or I can cut into the floor and put a new clean-out in there. Above the floor would certainly be easier from the manual labor point of view but I don't know if it will work as well for using a power auger.

LMHmedchem