Cast Iron Fernco / Wye Help (3/4" difference in spec)

[djfremen]

Hey Gang,

First post here. Thanks for having me.

I don’t have enough room to adapt to PVC so I went with No-Hub Cast Wye.

The issue is my 4x4x3 Charlotte Cast Wye is too small for the 1900’s extra heavy cast iron. (1/4" smaller)

See the images for a circumference comparison with a guide wire.

My concern is solids will snag on the small diameter when they go to the street.

What do I do? Does fernco make an adapter for extra heavy or can I get a different cast iron wye that is thicker?

Thanks,

 

[Terry]

You can't use a Fernco on cast iron pipe and fittings.
The coupling can be a shielded coupling, the kind with a metal wrap to prevent sagging of the pipe and rubber years later.

No-hub x copper is what you are looking for.

 

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[Reach4]

Does fernco make an adapter for extra heavy or can I get a different cast iron wye that is thicker?

See https://www.fernco.com/plumbing/shielded-couplings/proflex-couplings and look for the phrase "XH CI".

 

[djfremen]

Forgive my ignorance on this subject but even if I get the correct shielded pro-flex coupling, the wye will still be smaller than the original XH CI pipe... Or am I over thinking the 1/4" reduction in pipe circumference? Just trying not to upset a system in place for 80 years with tenants in the building. Also, I thought I read somewhere that shielded couplings couldn't be buried... other than a Anaco Husky type product. Thanks much.

 

[hj]

The inside diameters should be the same. If you use the correct coupling the insides will line up properly. You read wrong.

 

[djfremen]

Fits snug. Thanks again.

 

[Reach4]

Also, I thought I read somewhere that shielded couplings couldn't be buried

I think you read something else -- along the lines of unshielded couplings should only be used when buried.

 

[djfremen]

Ah... might be an old code: https://www.s1eonline.com/articles/2016/05/03/shielded-couplings-new-industry-standards

 

[hj]

It NEVER was code to not bury No-Hub connections. Your pipe is NOT 3/4" larger. If has 3/4" larger circumference so the pipe itself is only about a 1/4" larger which was the difference between SV and XH cast iron pipe.