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Condensate Drain Vent

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  • Condensate Drain Vent

    Hey'all

    Condensate drain line does not appear to be working right. It doesn't seem plugged. I checked pitch of drain/unit and it's OK. Someone had plugged the vent on the drain at the unit. Since unit is pulling a negative I "unplugged" the vent. Condensate is still building up and overflowing in the pan. What's up with that?

  • #2
    Can you see where the end of the condensate drains out?

    How long is the condensate line?

    If possible take a small hose and push down past the tee where the drain comes out of the unit. Try to run some water through the condensate line watching to be sure you don't run any back up into the pan under your evaporator.

    To really be sure it is good and clean you can do this: If there is room to cut the line free from your unit and still reconnect it with a coupling then go ahead and cut the line. Then take a garden hose and hold tightly to the end of the pipe. Run water through the pipe until you have a solid stream at the other end. Check the floor drain or what ever your condensate drains into to be sure it is not plugged also so you don't end up with a bigger mess than you started with.

    You can jury rig a fitting on the end to allow for a solid connection where you put the hose but it should only take a few monments to blow the snot (the general consistancy of a condensate blockage usually looks like nasal mucus) out of the pipe.

    Let us know how it went.
    Work hard, Play hard, Sleep easy.

    Comment


    • #3
      Thanks for the suggestion. The real head scratcher I had was whether there should be a vent there or not. I will definitely give the old drain clear out a try.

      Comment


      • #4
        TYPICALLY THE DISCHARGE END DRAINS TO A SINK TAILPIECE. A SHOP VAC CONNECTED TO THIS LINE WILL USUALLY HELP MOVE IT ALONG. ALSO A BLAST OF COMPRESSED AIR WILL BLAST IT FREE. JUST WATCH OUT FOR THE MUCK. IT WILL END UP WHERE YOU DON'T WANT TO CLEAN. A VAC IS MUCH CLEANER.
        ALL THE MUCK THAT IS STCUCK IN THE PIPE CAN BE WASHED AWAY IF YOU CAN ESTABLISH FLOW. ALSO A SMALL FISH TAPE OR 1/4'' CABLE CAN ALSO BE RUN FROM EITHER END. YOU PROBABLY WON'T GET PAST A 90 TURN. SO TRY FROM BOTH ENDS. YEARS OF BUILT UP MUCK MIGHT TAKE SOME EXTRA EFFORT.

        DEPENDING ON THE HUMIDITY AND THE SIZE OF THE UNIT, YOU CAN HAVE 5-15 GALLONS OF CONDENSATE FORM A RESIDENTIAL UNIT, PER DAY. LOTS MORE ON A COMMERCIAL SIZE UNIT.
        JUST THINK A LITTLE SWEAT WILL PAY OFF WITH A COOLER, DRIP FREE UNIT.

        GOOD LUCK RICK.

        Comment


        • #5
          My PVC Drain lines always get plugged with dust. So the pan overflow was always dripping on the floor. I just put a piece of 1/2 inch clear on the end of it and routed it down the drain. Usually once a year I'll go inside and blow all the junk out of the PVC.

          Comment


          • #6
            also

            Also you must make sure you fill the trap on the condesate line before you start up the unit or else it will not be able to start draining. (just sucking air into the unit) The vent (after the trap) should be left opened to eliminate the slight chance that the trap would be siphoned. (very unlikly but i guess possible) try draining when the unit is off to make sure the unit is not sucking the trap back into it. I guess this is not a problem since it has been working at one time. so as the others said a good clean is probably all it needs

            Comment


            • #7
              also

              Also you must make sure you fill the trap on the condesate line before you start up the unit or else it will not be able to start draining. (just sucking air into the unit) The vent (after the trap) should be left opened to eliminate the slight chance that the trap would be siphoned. (very unlikly but i guess possible) try draining when the unit is off to make sure the unit is not sucking the trap back into it. I guess this is not a problem since it has been working at one time. so as the others said a good clean is probably all it needs

              Comment


              • #8
                Mine used to overflow the pan, took me awhile to figure it out. The line looked level, but after putting a level on it it was running up hill. We all know water does not run up hill.
                SSG, U.S. Army
                Retired
                K.I.S.S., R.T.F.M.

                Comment


                • #9
                  you shouldn't have a vent on your drain unless it is after your trap. You do have a trap don't you?

                  Comment


                  • #10
                    Re: Condensate Drain Vent

                    Shut the fan off and observe the level of water in the pan.
                    If it drains the fan suction is holding the water.
                    Solution is to make the height of the drain trap = to the suction of the fan. Suggest you use transparent pipe for the trap

                    Comment


                    • #11
                      Re: Condensate Drain Vent

                      Originally posted by marrud View Post
                      Shut the fan off and observe the level of water in the pan.
                      If it drains the fan suction is holding the water.
                      Solution is to make the height of the drain trap = to the suction of the fan. Suggest you use transparent pipe for the trap
                      Please elaborate for us non-engineers

                      Comment


                      • #12
                        Re: Condensate Drain Vent

                        Originally posted by OkieBill View Post
                        Please elaborate for us non-engineers
                        Knowing the type of install would help

                        A typical furnace with a AC A-Coil on top would be a positive pressure coil/drain pan/drain

                        An Air handler's coil is typically upstream of the fan, thus the drain is under some negative pressure/suction.

                        Now if the trap, type of trap, location of vent, ductwork in inadequate, causing high static, all these will affect proper condensate drain, besides the obvious (drain pan or drain line pitch).

                        Comment


                        • #13
                          Re: Condensate Drain Vent

                          Originally posted by marrud View Post
                          Shut the fan off and observe the level of water in the pan.
                          If it drains the fan suction is holding the water.
                          Solution is to make the height of the drain trap = to the suction of the fan. Suggest you use transparent pipe for the trap
                          This is what I wanted explained

                          In my experience if you have an Air Handler holding water it is do to air not getting on top of the condensate. Proper line size is important where a slightly undersized line could get maxed out on a humid day thus not letting air flow through the pipe then the air handlers negative pressure causes complications of course each situation is different...

                          Comment


                          • #14
                            Re: Condensate Drain Vent

                            I agree with Okiebill, I say it may be too small of a pipe, for drain. I see lots of condensate drains run in 1/2". Our code here says minimum of 3/4". JMO

                            Comment


                            • #15
                              Re: Condensate Drain Vent

                              Originally posted by OkieBill View Post
                              This is what I wanted explained

                              In my experience if you have an Air Handler holding water it is do to air not getting on top of the condensate. Proper line size is important where a slightly undersized line could get maxed out on a humid day thus not letting air flow through the pipe then the air handlers negative pressure causes complications of course each situation is different...
                              I don't disagree with that, but that is also why vent stand pipes are added after trap to vent the long condensate drain.

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