Had a problem with the sewer system on the second floor.
Ended up opening up the wall on the first floor and had to cut out a
three-foot section of 4" cast iron sewer line. Sealed up the system by
installing a 3-foot section of 4" PVC (sch-40) using two 4" Fernco
I can't get the Ferncos to seal. The top Fernco weeps just enough to
show a moisture ring at the top. The bottom fernco has significant
leakage at the bottom. I tightened the clamps in stages with a
screwdriver and then switched to a ratchet with 1/4" bit. The Fernco
rubbers are simply not sealing on the cast iron.
Ugh. I'm at a loss. How can I seal this beast and still be able to get
access in the future???
I suspect that you used a flexible coupling like one of these:
these make no attempt to keep the piping lined up. I also suspect that
your new pipe is not a good fit in the old pipe run.
Change out the couplings to one of the shielded type:
"No Hub" clamps work well on cast iron/PVC connections.
These hold the pipe intersection in line. The new pipe should have an
1/8 to 1/4 gap at each coupling.
One person wrote,
"My guess is that your corrosion crack
is extending past the point that you cut."
I think that may be a possibility, especially since you wrote, "The top
Fernco weeps just enough to show a moisture ring at the top". Seeing that
on the top connection seems unusual to me.
But, if it is not a cast iron pipe that is still cracked, the other thing
that I would try is to sand/grind the outside of the cast iron to make a
smoother surface for the Fernco to seal with, and also add 100% silicone
caulk in the connection between the Fernco and the cast iron to help it seal
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