This is somewhat similar to my last question, but it's different enough that I am going to ask about it specifically.

I am trying to add a second bathroom to a house that was built in 1940. I have most of the waste/vent/drain plumbing figured out, except where I will connect to the sewer hub in the basement floor.

I have done something like this previously and I purchased a rubber donut that snuggly fit into the sewer hub. This allowed me to connect a 3-inch PVC pipe into the sewer.

In this case, I bought a 4-inch donut for a 3-inch PVC pipe (i.e. it is a reducing donut hub)... but this is too big for my sewer hub. I then bought a 3-inch donut hub for a 3-inch PVC pipe... and this is too small.

Are there other sizes available? Where might I find one for purchase? Should I be solving this problem a different way?

I'll try and post a photo soon.

Thanks,
Tim

Did you lubricate the outside of the 4" donut before inserting it in the hub? The 4: should fit. What's the outside measure of the donut? Let me know, Tom

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Originally Posted by speedball1

Did you lubricate the outside of the 4" donut before inserting it in the hub? The 4: should fit. What's the outside measure of the donut? Let me know, Tom

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My recollection is that the inside diameter of the hub is 4.5 inches. The photograph (which I still need to get off my wife's camera) includes a tape measure... so I can get that.

What would you use as lubricant? Perhaps that is my problem...

p.s. This is essentially what I have... although the website claims that there are no standard hub sizes

Fernco Flexible Donuts, fernco, fernco donut, fernco donuts, Sewer Pipe Compression Joint Donut Seal, Donut Shaped Compression Seal, Sewer Pipe Joint Seal, Pipe Compression Seal, Plumbing Donut Seals | Fernco


Here is the photograph of the sewer hub.

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What would you use as lubricant? Perhaps that is my problem...

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When we roughed in using dionuts we used Duel-Tite Lubricant , a heavy grease, to make the job easier. Insert the neoprene gasket into the hub. Grease the outside of the gasket before inserting. Now take a file and bevel the sharp edges so the pipe won't hang up on the ridges in the gasket. Next lube the pipe and the inside of the gasket with Dual-Tite Lubricant or a heavy grease. Push the pipe in until it seats on the bottom of the hub. If the pipe's difficult to start it's OK to trim back the first few ridges with a sharp knife. Good luck, Tom

Back in the old days they used to install 3.5 inch cleanouts once in a while. I bet Tom remembers those! You may have to lead this one in.