I'm replacing a section of sewer line that is cast iron pipe with ABS, 3". I'll be using a Fernco coupling to join the two. Do I need to bevel the end of the ABS then butt-joint it to the cast iron or just butt-joint them together?

 

It's not going to hurt anything if you want to bevel it, the less lip you have the better, otherwise debris can get caught on any sharp or protruding edges. Be sure to use a metal shielded Fernco.

 

Thanks, XSleeper for your response! I thought of using the metal shielding from Fernco, but thought it was not rated for underground? My bad for not clearly stating that the sewer line is buried underground!

 

That's correct. Not underground.

 

Got it! Thanks, again!

 

I've been pre-gluing (actually, welding) some connections together before I start the actual work. I noticed that despite twisting and pushing the parts together--such pipe to coupling--there seems to be a small gap. About a sixteenth to an eighth of an inch. I've attached a photo showing the gap. The end of the pipe stops just short of the coupling stop. This is a 3" ABS pipe, that will be buried underground. Is the gap a problem? The gap seems to be filled with ABS glue. Just would like to know before I proceed with further pre-connections. Thank you.

 

It's hard to tell from the picture, but from what you describe, 1/16" won't make a difference anywhere. When the second pipe goes in, it'll 'level' out. There's always going to be a little bit of a lip/divot where pipes join into fittings, you just don't want anything significant.

You're all good!

 

Thank you, Zorfdt, for your response!

So, I'm off to the races!

 

So, I completed my connections since my last post, and tested it out for about 6 days. No leaks, water seemed to be flowing just fine (I have a two-way clean out upstream from the section I replaced). Called for inspection and passed! Inspector signed-off. Afterwards, for a few hours, I started packing the dirt back into the ground. The next day, before I continued to repack the dirt, I was watching a load of laundry water flowing through the sewer line. It started to back up and out the clean out! (Stopped the machine, of course). I don't know what went wrong. I had the lined checked for stoppage, but the plumber didn't find any, but mentioned there was a lot of water in the line, per his camera. Thinks the slope is off. Maybe the way I was packing the dirt in threw the slope out of alignment? I had also replaced a long turn sweep and am wondering if there's some special considerations to use on the other end of sweep when attaching pipe for sloping concerns? For the last several days, I've been removing the dirt in the trench and have been realigning the slope, but it doesn't seem to help the water to drain out. I just kind of think it may have something to do with the sweep. Any thoughts are appreciated!

 

It is likely a clog somewhere. Even if the line was back-pitched, the most you should see is 1/2" - 3/4" water pooling at the bottom of the pipe. Not a good thing long-term as gunk can build up, but it certainly wouldn't cause a backup immediately.

How much pipe did you replace? How much of a pitch did you have on it before backfilling?

I ask because obviously a 40' run could have a section backpitched an inch or two as it was backfilled - whereas a 3' run really can't have much of anything.