I need to replace my galvanized tub drain pipe. It ran into an existing 3″ inlet in the side of my cast iron sanitary tee. The interior sides of the 3″ inlet are smooth, not threaded. Do I need a plumber to okam and lead a new metal drain pipe? Or can I use a rubber donut with 1 1/2″ pvc? Whats the best way? Thanks.
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Replies
Clean the existing hub real well & Use the rubber donut
How come your "PVC to Cast Iron" title doesn't in any way relate to the problem you afterward described? Next time you may wish to use "Day of Infamy," or maybe " War of the Worlds " as a subject for such an unrelated subject.
BARMIL, your posts are becoming nauseous.
>>doesn't in any way relate
>>doesn't in any way relate to the problem you afterward described?
What part of "It ran into an existing 3" inlet in the side of my cast iron sanitary tee" didn't you understand?
You will want to use a no-hub coupling to join the cast iron and the pvc.
Calling out pipe sizes can be confusing, and that's why you're getting conflicting advice. (No-hub coupling vs insertable donut)
When you say the tub drain ran into "an existing 3" inlet", do you mean that the OUTSIDE diameter of the inlet, or hub, is 3", or do you mean that the inlet is large enough to accept a 3" pipe?
In plumber's terminology, pipe sizes are called out by the INSIDE diameter of the pipe. But, just to confuse things, tubular sizes, like the parts that connect the sink to the waste line are are called out in OUTSIDE diameter--e.g. 1-1/2 p-traps and tailpieces, and 1-1/4 p-traps and tailpices. Thus, the outlet of an 1-1/2 tubular p-trap will fit inside a 1-1/2 drain pipe. Confused?
If you are going into a cast iron hub, use the donut. If it isn't a hub, then use a no-hub coupling. Torque the bands to 65 inch pounds, if possible.
The inside diameter of the inlet is 3".(like it was cut out with a 3" hole saw).
The donut I purchased seems like it may work fine. I'm just a little concerned about possible leaks because (1) this is a horizontal inlet, and (2) my kitchen sink drain empties into the cast iron stack just above this inlet. I don't want water to find its way between the cast iron and the donut. I was thinking of putting a little silicone at the bottom of the rubber donut where it meets the bottom of the cast iron inlet.