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  • Dishwasher Vent

    I am an amateur handy man around the house. I am remodeling our kitchen and have ordered a new counter top and sink. However, I don't want that nasty vent sticking up above my new quartz counter and sink.

    Can I mount the Y pipe under the counter instead or is that to low? Do I have to take the vent all the way under the floor to the outside of the house? (that would mean the vent hose would drop below the dishwasher)

    Any advice will be appreciated.
    Marti

  • #2
    Re: Dishwasher Vent

    Air Gaps are code in KY for keeping that "nasty" germ/bacteria laden waste from ever reentering your dishwasher in the event of a clog.

    I'm reworking a drain system after christmas where somebody dropped the Air Gap under the sink, lost its effectiveness and destroyed the base of the cabinet. I'm not coming back until all the black mold is gone, new surface to bottom of sink base.

    Air Gaps serve more purpose in the lines of backflow safety than what the end user is willing to understand.

    It protects in the event of a clogged kitchen sink drain; fluid dynamics will send that reversal of flow back to the dishwasher.....not knowing it has happened.


    You are gambling at best....
    Northern Kentucky Plumbers Twitter Feed | Plumbing Videos

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    • #3
      Re: Dishwasher Vent

      Marti,

      The dishwasher is required by the Uniform Plumbing Code but not by the International Plumbing Code. Oddly enough Washington adopted all International Codes with the exception of the Plumbing Code where they adopted the Uniform Plumbing Code. I reviewed Washington's amendments to the UPC and there was no exception for dishwasher air gaps. In other words you must install a dishwasher air gap to be legal.

      Mark
      "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

      I never lost a cent on the jobs I didn't get!

      Comment


      • #4
        Re: Dishwasher Vent

        when I was plumbing in Washington, a "Johnson Tee" was an acceptable alternative to the air gap.

        http://www.dalspc.com/Sub/pdf/Cat2005.pdf
        a johnson tee is on page 22.
        Last edited by BAPlumber; 12-21-2007, 04:19 AM.
        Brent

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        • #5
          Re: Dishwasher Vent

          I looked on page 22 at the Johnson Tee.

          I have no idea what the hell that thing is or what it's supposed to do.

          Please clue me in

          Comment


          • #6
            Re: Dishwasher Vent

            You don't need to mount the thing above the counter. It can be mounted just below with the proper hardware. Interestingly enough, quite a few new dishwashers have a trap and air gap built in. the ipc wants the drain hose looped and clipped to the highest point under the counter top, but this effectivly double traps the fixture, which is a code no no. Sometimes you have to do a it of explaining to the inspector and perhaps have a copy of the code handy.
            sigpic

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            • #7
              Re: Dishwasher Vent

              Originally posted by plumberscrack View Post
              I looked on page 22 at the Johnson Tee.

              I have no idea what the hell that thing is or what it's supposed to do.

              Please clue me in
              I don't think anyone has installed one in our area in the last 40-years but they are an approved and listed air gap under the UPC. Just like a standard air gap they must have a critical line which is higher than the flood rim of the fixture. The main difference is unlike a standard air gap which is installed in the counter top or sink ledge and then drained via a 7/8" hose to the dishwasher the Johnson Tee has a separate 1 1/2" trap and riser in the wall that the Johnson tee sits on. You then have copper in-wall piping running from the dishwasher area and then making a loop above the Johnson Tee and tying in to the top of the Johnson Tee. The vent can then either be through the splash above the sink or out through the exterior wall. They are a good system but add quite a bit of cost to a dishwasher rough in.

              Mark
              Last edited by ToUtahNow; 12-21-2007, 11:14 AM.
              "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

              I never lost a cent on the jobs I didn't get!

              Comment


              • #8
                Re: Dishwasher Vent

                Okay I found some photos of a Johnson Tee installation and vent.

                Mark
                Attached Files
                "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

                I never lost a cent on the jobs I didn't get!

                Comment


                • #9
                  Re: Dishwasher Vent

                  Okay never mind it looks like they are no longer available even if you wanted to install one.

                  This is from the IAPMO Listing pages:

                  Generated On: 12/21/2007</I>

                  File Number: 1926
                  Product Description:Airgap Fittings (Dishwasher Waste)
                  Listee: JOHNSON INDUSTRIES, INC.
                  1015 S MYRTLE ST
                  SEATTLE, WA 98108
                  CANCELLED
                  Expiration Date: no data
                  Identification:
                  Manufacturer's name or trademark, model number, Flood level, and UPC® certification mark.


                  Characteristics:

                  Dishwasher drain airgap made of listed plastic DWV material. The airgap meets or exceeds the requirements of IAPMO Property Standard PS 23 and shall be installed in accordance with the manufacturer's instructions and the provisions of the latest edition of the Uniform Plumbing Code.

                  Models:
                  6/18/04-file canceled at applicant's request/no longer producing, JUNE PRC - tk AG-4P Johnson Tee

                  Additional Companies:


                  Additional Company Info:






                  Mark
                  "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

                  I never lost a cent on the jobs I didn't get!

                  Comment


                  • #10
                    Re: Dishwasher Vent

                    Thank god we don't have to do that here. How long would that trap last on an outside wall in our weather.
                    sigpic

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                    • #11
                      Re: Dishwasher Vent

                      Originally posted by NHMaster3015 View Post
                      You don't need to mount the thing above the counter. It can be mounted just below with the proper hardware. Interestingly enough, quite a few new dishwashers have a trap and air gap built in. the ipc wants the drain hose looped and clipped to the highest point under the counter top, but this effectivly double traps the fixture, which is a code no no. Sometimes you have to do a it of explaining to the inspector and perhaps have a copy of the code handy.


                      I've read your response and can't understand it. Can't tell what you're expressing.


                      The only way an Air Gap serves its purpose is only when the device is above the flood level rim it serves. Any Air Gap open to the free atmosphere at the dishwasher (moisture, possibility of error in a concealed location) would be at a minimum, 2" below flood level. The "Critical Level" is the point at where the device may become submerged and backflow may occur. These are predetermined settings set forth by all regulating commissions.



                      Clipping the hose and high looping under the sink is the same as draining a pool with a garden hose draped over the edge, the end of that hose at a lower elevation to provide fluid dynamics to start the siphon process.

                      The first plunger to the sink drain and/or the waste level rising to the flood level rim at which the fixture will over flow, it will travel to the dishwasher.

                      Built-in check valves on dishwashers do not supercede local authority codes in the removal of an Air Gap.


                      An Air Gap is mandatory on all commercial industrial applications on the idea and premace of dishtank equipment, there is absolutely no reason the code should be relaxed down to the residential level just because the likelihood is less.

                      In my opinion in all that I've seen in my days as a plumber, the risk is higher on the residential level.
                      Last edited by DUNBAR PLUMBING; 12-21-2007, 12:02 PM.
                      Northern Kentucky Plumbers Twitter Feed | Plumbing Videos

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                      • #12
                        Re: Dishwasher Vent

                        Originally posted by DUNBAR View Post

                        Built-in check valves on dishwashers do not supercede local authority codes in the removal of an Air Gap.
                        The IPC allows a loop to the bottom of the drain board and NO air gap if the dishwasher has it built in.

                        Mark
                        "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

                        I never lost a cent on the jobs I didn't get!

                        Comment


                        • #13
                          Re: Dishwasher Vent

                          the higher end european machines have an automatic check valve built into the water supply. all of the local inspector accept them as designed and approved. they don't require an air gap.

                          has anyone ever serviced a dishwasher? sure you can get waste water in the machine, but that's what the dishwasher was designed for.

                          there is a built in air gap on the water fill to the tank. i will try to get a picture today as i have a new one at my shop.

                          same with a washing machine.

                          rick.
                          phoebe it is

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                          • #14
                            Re: Dishwasher Vent

                            Thanks Rick, Good explanation. The codes have gone round and round for years over this issue. I live right on the Maine boarder, a upc state, and they have required the chrome mushroom for years. Homeowners hate it and I can't say I blame them. You put in a thousand dollar Kohler sink and faucet and then stick that ugly assed thing on top. I have honestly in 35 years of plumbing never seen a back flow problem involving a dishwasher. I can see hot it might be possible though.
                            sigpic

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                            • #15
                              Re: Dishwasher Vent

                              Originally posted by PLUMBER RICK View Post
                              the higher end european machines have an automatic check valve built into the water supply. all of the local inspector accept them as designed and approved. they don't require an air gap.

                              has anyone ever serviced a dishwasher? sure you can get waste water in the machine, but that's what the dishwasher was designed for.

                              there is a built in air gap on the water fill to the tank. i will try to get a picture today as i have a new one at my shop.

                              same with a washing machine.

                              rick.
                              Wait a minute. I thought the main purpose of the air gap was to keep waste water out of the dishwasher and off the clean dinner plate being served to me.

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