Copper Drain to PVC - Fernco Tee?

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LCF

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I need to tie a new PVC sink drain into an existing and old copper stack.

Is a Fernco tee like attached the best way to do this? I don't think they make reinforced Fernco Tee's and I hate the idea of using it, but I don't see another way.

Also, what is the best way to cut the copper? A hack saw? I don't think I have enough clearance to use a pipe cutter that wraps around the pipe while you turn.
 

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wwhitney

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Definitely no on the all rubber tee. I'm not aware of any approved permanent use for them.

Is the horizontal copper in your picture a sink trap arm that depends on the stack for venting (not good, the wye plus 45 should be a san-tee instead) or an already vented horizontal drain (no problem)? Perhaps moot if your work involves replacing it rather than adding a new san-tee above or below.

The way to marry some new PVC with an existing portion of that stack is to use 2-3 (depending on what all you are cutting out) shielded rubber couplings made for PVC to copper transitions. I.e. depending on size, Fernco 3001 or 3007 series, or Mission Rubber CK or PK series.

As to cutting the copper, someone with more experience may know what way is best, but with care you could do it with a hacksaw, a reciprocating saw, an oscillating saw, or even an angle grinder. Just file and deburr afterwards to get nice smooth, square ends.

Cheers, Wayne
 

LCF

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Definitely no on the all rubber tee. I'm not aware of any approved permanent use for them.

Is the horizontal copper in your picture a sink trap arm that d on the stack foependsr venting (not good, the wye plus 45 should be a san-tee instead) or an already vented horizontal drain (no problem)? Perhaps moot if your work involves replacing it rather than adding a new san-tee above or below.

The way to marry some new PVC with an existing portion of that stack is to use 2-3 (depending on what all you are cutting out) shielded rubber couplings made for PVC to copper transitions. I.e. depending on size, Fernco 3001 or 3007 series, or Mission Rubber CK or PK series.

As to cutting the copper, someone with more experience may know what way is best, but with care you could do it with a hacksaw, a reciprocating saw, an oscillating saw, or even an angle grinder. Just file and deburr afterwards to get nice smooth, square ends.

Cheers, Wayne

I like the idea much better about using 2 shielded rubber couplings to connect to PVC with a PVC sani tee in the middle. I didn't even think of that. Thank you! The horizontal line you see to the left of the stack is an already vented drain.

I prefer the idea of angle grinding the pipe, but I don't think my grinder would go deep enough to cut through so I am considering all options.
 

wwhitney

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The horizontal line you see to the left of the stack is an already vented drain.
OK, are you sure the stack has no drainage from above? It's just an unnecessary vent stack? Or do you have another plan for venting your new sink?

Cheers, Wayne
 

LCF

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OK, are you sure the stack has no drainage from above? It's just an unnecessary vent stack? Or do you have another plan for venting your new sink?

Cheers, Wayne

There used to be drainage above, but I am no longer using that sink so it's being closed off. The new sink I am installing will have an air admittance valve. This is an old barn. Not a house.
 
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Tuttles Revenge

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Definitely no on the all rubber tee. I'm not aware of any approved permanent use for them.

Is the horizontal copper in your picture a sink trap arm that depends on the stack for venting (not good, the wye plus 45 should be a san-tee instead) or an already vented horizontal drain (no problem)? Perhaps moot if your work involves replacing it rather than adding a new san-tee above or below.

The way to marry some new PVC with an existing portion of that stack is to use 2-3 (depending on what all you are cutting out) shielded rubber couplings made for PVC to copper transitions. I.e. depending on size, Fernco 3001 or 3007 series, or Mission Rubber CK or PK series.

As to cutting the copper, someone with more experience may know what way is best, but with care you could do it with a hacksaw, a reciprocating saw, an oscillating saw, or even an angle grinder. Just file and deburr afterwards to get nice smooth, square ends.

Cheers, Wayne
Agree with all the above including the cutting methods. A 6" fine tooth metal blade on a Recip saw would be the best. I suggest cutting most of the way through on your first cut.. leaving enough material that it stabilizes the other cut. Cut the second cut all the way, then finish off the first.


Just a couple FYI's concerning the Fernco Tees...

1- they're not a full 1.5" or 2" through the tee, so therefore a restriction.
2- they're Iron Pipe Sized which is much larger than the outside diameter of copper DWV pipe size
 
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