Replacing cast iron with ABS, no hub coupling or donut?

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Skhunt42

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Hello, long time lurker and first time poster. I’m installing a new vanity and the drain sits too low. I have an option of cutting a fairly large hole in the cabinet (particle board) to clear the p-trap but I would like to weigh out my options. An s-trap is against code here in California.

I have the drywall torn out already and I figured it would be a good idea / beneficial to replace a section of the cast iron with ABS since it’s already exposed.

Would it be in acceptable to just cut where the red lines are and run a no hub coupler? Are there any reasons to actually cut the lead joint and run a donut instead?

1F2B53A3-14A9-43A1-94F9-2DB1CD662CC3.jpeg
 
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Skhunt42

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You can do either, my preference would be for the donut with 2" pipe into the 2" hub.
Hey Terry! Thanks for the reply. I discovered a post where you also mentioned this but can you follow up with a benefit over a no hub coupler? Is it just preference?

After a few days of researching on here I’ve come to the conclusion that it’s more tedious to run the donut due to cutting the existing lead out and finding a proper size donut.
 

Terry

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It's also a bit tricky finding a coupling that fits old cast iron pipe.
Removing lead from a 2" hub has always been easy for me.

index.php


The donut allows me to use a 2" pipe.
No grinder needed and super easy to do.
 
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Jeff H Young

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I never did it Terry's way . I think his way looks cleaner I just make 2 cuts though and don't have to get precise measurements etc, probably making more out of it , just sort of preference
 

breplum

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We always cut the C.I.
Sometimes have to grind down seams that old C.I. often has.
Mini-grinder is the tool needed there.
 

Skhunt42

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Just flawlessly cut the galvanized pipe that connected to the cast iron pipe. The galvanized OD measures at 50mm and the cast iron OD measures at 60mm. The plumbing supply store says I would be okay with just a 2" (50mm) shielded no hub for both pipes.

Would you guys agree with the plumbing supply store?
 

Terry

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Just flawlessly cut the galvanized pipe that connected to the cast iron pipe. The galvanized OD measures at 50mm and the cast iron OD measures at 60mm. The plumbing supply store says I would be okay with just a 2" (50mm) shielded no hub for both pipes.

Would you guys agree with the plumbing supply store?
A guy that has never done plumbing, works at a hardware store giving out advice.
They make couplings with with many dimensions. If you are going from galvanized steel to plastic (PVC or ABS), they make couplings for that. Normally the OD of galvanized to plastic is the same. Cast iron can be a few different sizes. Some old stuff is more like a copper size.

Most of the time when I remove galvanized waste lines, they are barely draining anymore. Why would anyone leave them there?
 
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wwhitney

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The galvanized OD measures at 50mm and the cast iron OD measures at 60mm.
That means the galvanized pipe is 1-1/2" nominal (1.9" OD) and the cast iron is 2" nominal (2.3" OD). So you'd want a 2" schedule 40 x 1-1/2" schedule 40 shielded coupling. E.g. Fernco 3000-215 or Mission Rubber CP-215, if you need to connect those two.

Although if the galvanized is a drain (haven't been following the thread), better to remove all the galvanized.

Cheers, Wayne
 

Skhunt42

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Are you using a meter stick to measure? I suggest that you get a digital caliper with a big-enough jaw to measure your bigger pipe. https://www.harborfreight.com/hand-...eter/calipers/6-in-digital-caliper-63711.html should do it well. https://www.harborfreight.com/hand-...ers/6-in-composite-digital-caliper-63586.html is probably adequate for less money and fewer digits.

That’s exactly what I used to measure the pipes. Although the battery ran out and I rounded up a bit. Should I find a cast to ABS coupling at 60mm instead of attempting to stretch it over?
 

wwhitney

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For 2" CI (~60mm OD) to 2" Plastic (2-3/8" OD), use Fernco 3000-22 or Mission CP-200. For 1-1/2" galvanized (~50 mm OD) to 2" Plastic (2-3/8" OD), use Fernco 3000-215 or Mission CP-215.

Cheers, Wayne
 

Skhunt42

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That means the galvanized pipe is 1-1/2" nominal (1.9" OD) and the cast iron is 2" nominal (2.3" OD). So you'd want a 2" schedule 40 x 1-1/2" schedule 40 shielded coupling. E.g. Fernco 3000-215 or Mission Rubber CP-215, if you need to connect those two.

Although if the galvanized is a drain (haven't been following the thread), better to remove all the galvanized.

Cheers, Wayne

Hey Wayne, I have to run an abs San tee between the 1.5” galv and 2” ci. Do you have the part number for those?

Disregard, the post above did not load until now.
 

wwhitney

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Hey Wayne, I have to run an abs San tee between the 1.5” galv and 2” ci. Do you have the part number for those?
For 1.5" galvanized to 1.5" ABS, it's 3000-150 or CP-150.


(Galvanized is Steel, which appears as ST in the chart).

Or you could just use a 2" san-tee, with a 2" ABS stub on the vent, and use the 3000-215 / CP-215 to connect the 1.5" galvanized to the 2" ABS.

Cheers, Wayne
 

Skhunt42

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For 1.5" galvanized to 1.5" ABS, it's 3000-150 or CP-150.


(Galvanized is Steel, which appears as ST in the chart).

Or you could just use a 2" san-tee, with a 2" ABS stub on the vent, and use the 3000-215 / CP-215 to connect the 1.5" galvanized to the 2" ABS.

Cheers, Wayne

I'm going with the second method you posted below, thank you guys all for the advice!
 
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