My problem is -

I have 2 sinks. The sink on the left goes down to the right and enters to the downpipe on sink on the right above the s-bend via a T piece. The downpipe line from left sink to right sink downpipe also has a 1 inch drop. I also have a dishwasher that connects to the nipple in the s-bend also.

I have taken apart all downpipe lines, bends and sections and cleaned. Although there were no build ups or blockages. I bought some Draino (Sodium Hydroxide) and followed the instructions. I knew this would only work on the downpipe lines up the S-bend, but I had to do this. I then disconnected the s-bend and placed a garden hose into the downpipe and turned it on. I had no backup of water (which I didn't expect) with the hose running full bore for a couple of minutes.

However, when I turn the tap on for sink on the right it backs up on itself and also starts to fill sink on the left as you would expect with a backup.

I also put an application of draino, using a funnel) directly down the main downpipe line, after I tried the hose. Still no solution. The sink continues to back up. I also blanked off the nipple where the dishwasher enters into the s-bend just to see if this for some unknown reason had an effect. None.

I am confused. Can anyone off any possible insights. I live in Northern NSW, Australia.

Any help would be greatly appreciated.
Thanks

Echo, take a look at this link and lets see if we can use some traditional plumbing terms to desribe your situation. Also, stop putting Draino and a garden hose together in the same pipe, your can burn your eyes out as well as skin. http://www.hammerzone.com/archives/kitchen/sink/stainless/drain.htm

Echo1... Bob's link is missing for now. I am sure he will post it when he discovers that fact... ;)

For now, tell me if these sinks have always been an issue for you? Also, tell me what happens when you run the dishwasher? Curious why that is not an issue mentioned here...

Anyway, I'm thinking you could have a big issue with venting here. That is, you may not have a vent on the sink.

But to know for sure we would need to know if this is a new issue or one that has always been an issue? If you can post a picture here that would be even better.

Let us know...

MARK

Thanks for the responses. After some more flushing with the hose, the blockage cleared. The downpipes to the sink go across a horizontal to the main downpipe to the sewer line. The Hot Water and or the Draino must have dislodged the fat chunk (about 1" thick). Without realising this it then went further down to block up all lines to the main sewer. Luckily the breather vent for this started overflowing with water and we were able to dislodge this and dissolve with some more Draino. Couldn't understand how a hose flow previously wouldn't back up when the normal sink function would.

Thanks for the replies.
All fixed for now.

Regards
David

Hey Mark, thanks for the heads up, link is now back.