In the Part 1 of this guide to installing a double kitchen sink drain, you learned how to fit the drains to the sink and attach the fittings to the wall. In Part 2, you will attach the drain outlet pipes together and place the fittings on the trap arm. You will also learn how to avoid basic beginner mistakes. Once the hard parts of the task—such as the original fittings on the sink—are completed, then the rest of the installation of your double kitchen sink drain should not be too difficult. With a few basic skills, you should be able to do this job in a couple of hours.
Step 1 - Add the Second Drain Pieces
Once you have got the first tail pipe added to the drain, you can then attach the outlet drain to the t-fitting, and then to the second drain tailpiece. This should be done by adding a washer, with the beveled edge facing towards the second tailpipe. When you have added this drain outlet to the fitting, you should tighten it as much as possible. Ensure that both drains are covered by the drain outlet pipe. Add a layer of pipe grease to the outlet end of the pipe.
Step 2 - Attach the P Drain
When the outlet drain has been added to both of the drains, you can then attach your P drain fitting to the top of the outlet pipe, and screw it into the T-fitting. Using the washer, you should screw the top of the P pipe into the bottom of the outlet drain, and place a second washer on the other end of this fitting. Keeping the P angle in position, you should then tighten the bottom side of the drain. Make sure that you tighten that the edge of the pipes, so that it holds it together, and that there are no leaks between the edges of the pipes.
Step 3 - Finishing
You can then add some plumbers tape to each of the joints, tying it tightly around the edge of the joint. The nuts should be screwed onto each of the fittings, and then attach tape to the edge of the pipe, and tightening it. Make sure that the pipes are not leaking before you screw it in.
Step 4 - Mistakes and Errors
It is sometimes possible to make a number of errors in this simple installation. The biggest problem is not to install the fitting to the second drain. Without this second fitting the whole pipe may leak. You should also take care to ensure that all of the joints are fitted together tightly, and covered with plumbers tape, otherwise the water pressure may force the joint apart, and this would result in a leak. You can also have a problem in fitting the drain if you do not put the putty on carefully, it will not stick properly onto the sink.