Fernco coupling failure?

I cut out a vertical section of 4" cast iron and replaced it w/a section of 4" PVC, tied to the remaining cast iron w/ 4" Fernco mission style rubber couplings on each end. The bottom coupling leaks from the cast iron side of the joint. I don't think I can tighten it anymore, and it still leaks!

I don't know what to do - is it a bad coupling or could the cast iron have a deformity. The cast iron looks ok and the cut I made was very clean. Would a banded rubber coupling work better?

This has never happened to me before. Any suggestions?

Thanks.

Unless it is underground, you need the no-hub connector to be legal. Try one of them and see what happens.

Like jadnashua said code is banded couplings above ground and rubber coupling with hose clamp style bands on the ends for underground.

You have to use special transition couplings....
The rubber is thicker on the cast iron side than the ABS side and they have stainless steel sleeves over the rubber...
Otherwise the joints will distort and leak...

I am working in the basement ... is this considered underground? I was under the impression that banded couplings are required when working in walls to prevent a nail or screw from entering, but that mission style was acceptable for CI to PVC in a basement.

Wrong...you have the wrong idea about the band - it is to keep the ends of the pipe aligned. Underground, you backfill the hole properly, and that keeps the pipes aligned. A nailing flange is a totally different thing.

salpher said:

I am working in the basement ... is this considered underground?

Click to expand...

If it will be covered with dirt it is underground, if it is not it is above ground.