Thursday, June 3, 2010


We have lived without a dishwasher for almost 7 years and I thought we could get by a little longer but I was wrong.  Our dishes that have figured out how to reproduce by themselves and it's time for some birth control!

Today is the day that our new dishwasher will be delivered!  It won't be hooked up but it will be in the house, which is a step in the right direction.  I had hoped that the new kitchen island would have been ready but that didn't go as planned.  Turns out it was better that the island wasn't set because we decided to switch positions of the sink and dishwasher.  It would have been terrible to cut holes in the wrong locations in the cabinets!

We also need to properly vent the island sink.  Of course the original island sink was not vented and only worked because it was a double sink with one of the sinks serving as a vent.  I searched online and found a few ways to vent the sink.
  • Provide a loop vent according to the Uniform Plumbing Code
  • Provide a loop vent according to the International Plumbing Code
The Air Admittance Valve would be the easiest to install and take up the least amount of space under the sink but I wasn't able to determine if it could handle the discharge from the dishwasher.

The loop vents are similar in both the Uniform and International Plumbing Codes.  The difference is that the uniform code has a separate branch out to a vent to the roof.

I'm opting for the International Code, not because it will be easier.  Well, actually I am doing it because it will be easier as running a separate vent 3 1/2 stories up and through the roof is not something I really want to do.  And tying into the existing stack would be equally difficult if not impossible. 

I'm fairly confident that the International Code will work fine but if not I could always add the branch in later.  I will post the results when done.


plumbob said...

your diagram on the uniform plumbing code is not correct. You show the Tee for the vent thru the roof upside down. If you can't draw the diagram, I doubt you have the knowledge or skill to actually do the installation. You should call a licensed professional.

Forest said...

Wow, thanks for the comment (I think). Just for the record, I did not draw the diagram and put it up in an attempt to illustrate the different options. If I were to draw the diagram I would have shown a true tee fitting that would not have an up side or down side.

Also, just for the record, I am a licensed Professional Engineer and if I happen to read something in a blog (in my field) that I believe is not correct or dangerous I try to offer constructive comments. Your statement implies that you are familiar with the Uniform Plumbing Code. Though I wouldn't use the fitting shown in the diagram would you care to elaborate on why it is upside down?