No announcement yet.

help!!TRAIN roof top unit

  • Filter
  • Time
  • Show
Clear All
new posts

  • help!!TRAIN roof top unit

    I have a big AHU which feeds the core area and many offices of my building and can’t seem to control the temp.

    It seems to blow pretty hard through the ducts. I have tried 3 different pulleys and there are no dampers in the diffusers to manually control it.

    I have the temp set at 76 f .

    The first floor the temp in the offices are 69F the second floor the temp is 72 f and the third floor the temp is 66 to 69.F

    The thermostat is on the second floor.

    The problem first began 1 month ago. The unit froze up because the pulley was worn and I had the coils cleaned for the first time in three years. I just took this building over`

    I have had three A fitters look at it and they all say the unit is running great.

    I now am in the process of trying to get the system balanced. I’m not sure if this is a wait of time as there are no adjustments on the ducts to be maid??

    Any advice would be much appreciated

  • #2
    se other post

    My seek the peek fundraiser page

    new work pictures 12/09


    • #3
      On track

      I think you are on track getting the system balanced. Make certain the coil was cleaned properly by shining a light through it and using a mirror.

      "I have tried 3 different pulleys", the correct pully needs to be on. Check and set the motor amperage as you may over amp the motor and cause a premature failure. I am not sure why you changed the pulley, was it to improve air flow??

      Check temp drop across coil, that will tell you somewhat what the system is doing.

      If you don't get the issue resolved call a knowledgeable tech and look over his shoulder to see what he fiinds, it would be a good teaching lesson for you. Tell him what and why you are doing that and most guys will take a little extra time to bring you up to speed.

      I found years ago not to make my own problems, the unit has a problem and you add another. Like changing the pulley unless they are failing. There is nothing more difficult than multiple problems with a system. Such as low air flow combined with low charge or a bad tx valve, really confuses a person.

      Put the same diameter pully back on as per mfr's spec so as to bring the system back to original. Once you find it needs to be a larger or smaller then change it but remember don't make your own problems. Find out what is wrong then fix it.


      • #4
        Hey thx for the good advice thorn.I will do that