Joining Copper to Galvanized

jelly · 09-12-2011, 09:35 PM

I have an issue with my drain, whenever I force water aggressively down my sink drain with my disposer, the water tends to back up into the bathroom sink.

The picture below shows my kitchen sink disposal drain (1) and my bathroom sink drain (2) These 2" copper lines meet then go into the galvanized waste line where I suspect the build up is.

I've read that over time the copper and iron react causing mineral build up. Since I am not in a position to replace the iron, would you recommend a dielectric union in the case?

How do you think it is joined now? I can see this opening a can of worms.

Cheers.

jelly · 09-12-2011, 09:44 PM

Closer picture of transition. Sorry for the poor quality.

**TheEplumber** · 09-12-2011, 09:53 PM

The pipe is cast iron although it looks galvanized. The union will not help you either. You have a partial blockage in your line. How well does your toilet flush. Is it ever slow or back up on you?

jelly · 09-12-2011, 10:07 PM

Quote:

Originally Posted by TheEplumber

The pipe is cast iron although it looks galvanized. The union will not help you either. You have a partial blockage in your line. How well does your toilet flush. Is it ever slow or back up on you?

Hi, the toilet didn't flush well until I replaced it, now it flushes just fine. Do you think there is a reaction happening between the metals causing the blockage? Is it safe to say I have pinpointed the area of the problem since all other drains work fine?

**TheEplumber** · 09-12-2011, 10:30 PM

If I was you I'd go rent a small drain snake and cable the kitchen line. While your at it, cable the lav too. Be sure it gets into the 4" a little bit.
IMO, the copper pipe will develop leaks before you have a major corrosion issue

jelly · 09-12-2011, 10:44 PM

When you say "rent" it leads me to believe it is a powered snake.

or are you recommending a simple snake like this?

Alan · 09-13-2011, 12:12 PM

You definitely want a powered snake.

We use the general wire ones with a small drum attached to the end of a drill.

When I do kitchen lines that have galv or cast iron fittings in them I usually use the 3/8 cable with a drop head on it. If you can get the cable to go DOWN the drain instead of up the vent, you probably could use a grease cutter head, but it kinda depends on what you've got down there. Could be a hair buildup from the lav even, so a boring gimlet head would be good for that. You might have to run it down several times to fully clear the blockage.

Good luck.