Lowering kitchen sink drain height - copper drain pipe

[pianomannick]

Hello


I'm renovating my kitchen and wanted to add a garbage disposal. House was built in the late 50s and drain enters wall too high for a disposal to fit. As you can see in the picture, I have copper drain pipe. It seems easy enough to just cut and add a Fernco coupling at the height I need it to be. However, the threaded 45 degree vent piece threads right into the tee for the drain. Does anyone have any suggestions for a way to tie into the threaded vent pipe?


Thanks!
Nick

 

[Twowaxhack]

Take another pic with a wider view.

I’d like to see where the copper goes to the left and how the vent is installed in relation to everything…….

There are rubber/stainless adapter couplings to transition between materials. Commonly referred to as ferncos or mission bands.

 

[pianomannick]

No problem. See attached for wider view.

 

[MicEd69]

The only problem you have is that the copper sanitary tee is pretty close to the outside wall. Cut the vertical line below the tee leaving enough pipe to connect the proper Fernco. One approach would be to not disturb the galvanized vent line and cut the branch off the sanitary tee as close to the tee as you can. That will allow you to unscrew the tee from galvanized street 45. Clean up the threads on that fitting with a wire brush and you can then use a threaded PVC fitting to screw onto the fitting. Makeup the assembly with a PVC sanitary tee, short pieces of pipe, a sink drain adapter, and a P-trap. Use the proper Fernco to attach the PVC to the cooper drain line.

Another approach would be to cut the copper line as desrcibed above, and then carefully unscrew top part of the upper 45 from the vertical pipe. That will allow you to unscrew the copper sanitary tee without having to cut off anything.

The galvanized pipe is only a vent, and probably won't cause you issues. But you may want to consider replacing it with PVC as you are into this renovation this far.

 

[TomFOhio]

If it was mine I would cut below the tee and put a SS band and then cut above the 45 and put a band
there and then pipe the rest with PVC or ABS which ever you prefer. Make sure everyone in the family
knows to put a little at a time in the disposal and lot of water following it. It will last a long time and
the drain won't get clogged as easy.

 

[Twowaxhack]

Let it be known that copper kitchen sink drains are famous for the bottom rotting out of it.

Acidic dishwasher soaps.

Have a great day

 

[MicEd69]

Let it be known that copper kitchen sink drains are famous for the bottom rotting out of it.

Acidic dishwasher soaps.

Have a great day

Usually in a copper P-trap though, right? The copper drain line here will normally be "dry" without sitting water in it.

Note this is a question, not a statement. Just wanting a little education here from a pro.

 

[TomFOhio]

Most of the copper drain lines that I've seen ate out are on the top and usually the main drain
because of not flushing the toilet.

 

[Twowaxhack]

Usually in a copper P-trap though, right? The copper drain line here will normally be "dry" without sitting water in it.

Note this is a question, not a statement. Just wanting a little education here from a pro.

The waste arm and all copper piping on a k-sink drain.

The trap is usually cast brass, not copper.

Automatic dishwashing soap is acidic. It eats the bottom of the pipe out where the flow is over the years. Most copper drains are over 50 years old now.

It’s so common that I routinely diagnose the problem over the phone for the customer.

 

[Twowaxhack]

Most of the copper drain lines that I've seen ate out are on the top and usually the main drain
because of not flushing

Most of the copper drain lines that I've seen ate out are on the top and usually the main drain
because of not flushing the toilet.

I’ve found them eaten alive from sewer gas. Sewer gas is acidic. It can cause cast iron stacks to split and copper to be eaten away.

The higher the concentration of gas the more likely it is to happen.

 

[TomFOhio]

I guess he could cut the pipe clear back to the main line tee and run plastic from there. That would
get rid of the copper and it wouldn't be hard to do.

 

[Twowaxhack]

I’m not trying to say one way is right and another way is wrong. I want that to be clear.

I usually heat the cast iron hub up enough that you can’t touch it with bare hands. But don’t over heat it.

Don’t start a fire……wet the area and remove flammable building materials.

Once the cast iron is good and hot( don’t heat the copper ). I use a pipe wrench to remove the copper male adapter while the cast is expanded from the heat. Lock the wrench onto the male adapter and kick it like you’re starting a motorcycle.

 

[pianomannick]

Thank you all for the replies! I certainly have a few options now. Actually someone had also suggested I could leave the existing copper tee as a cleanout and put my new pvc tee and drain in right below it. That way I didn't have to deal with the threaded galvanized vent. I appreciate the help.

 

[sawsaw]

or, you can reconsider and scrap the addition of a disposer. At a plumber's reccomendation, I discarded my disposer. Just set a little strainer trap on top one of the strainer baskets to catch little things. All garbage/waste goes in the garbage. Why did I do this? About every three years, plumbrr had to clear the drain line. About six years have passed and not one problem with the drain line. Plumber had said, more and more people were choosing this course of action.

 

[MicEd69]

or, you can reconsider and scrap the addition of a disposer. At a plumber's reccomendation, I discarded my disposer. Just set a little strainer trap on top one of the strainer baskets to catch little things. All garbage/waste goes in the garbage. Why did I do this? About every three years, plumbrr had to clear the drain line. About six years have passed and not one problem with the drain line. Plumber had said, more and more people were choosing this course of action.

I still have a garbage disposal, but I take all the garbage out of the sink, and only use it for the small pieces that are left.

 

[TomFOhio]

Thats usually how we it to. We've had our insinkerator for about 25 years. Wouldn't be without it. If you
use it right they will last a long time with no problems.

 

[Twowaxhack]

There are neighborhoods here that are on gravity drains city sewer but have a settling tank buried in the front yard

It’s a small septic tank but the outlet goes to city sewer.

All the gravity drains in the 3,000+ house neighborhood lead to a pumping station. From there is makes it’s way to the areas sewage treatment plant.

When you set up an account with the water/sewage provider you agree that you will not install a garbage disposal.

If they start getting excessive grease build up in their pump station, they have the option to camera each lateral and trace the source of grease. Then they’ll bill you for all the work.

A disposal that’s used as the manufacturer intended is bad for your drain pipes. The less grease and oils that enter the drain system the better. The less food that enters the system the better.

Your body is the first stage of sewage disposal. Your body breaks the food down, a disposal doesn’t.