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    Another lost neutral

    Went on a call yesterday where the problem was an open neutral. It was a power company problem as their cable had the open.

    Here is the question. Open neutral may have caused the AC compressor to burn/short. May have been a coincidence.

    It was a Lenox unit and only a couple of years old. High efficiency unit with speed controlled compressor. An HVAC tech was there and he seem to think that a lost neutral would effect the control module for the compressor.

    Anyone ever seen or herd of a lost neutral causing an AC compressor to lock up and short out. I would have figured that the controller board in the air handler would have burned and shut the unit off during a power surge like that but would like other opinion or comments.
    The 95% of people that you can't trust give the other 5% a bad name.

    #2
    AC unit is 120V?
    If Billy Idol is on your playlist go reevaluate your life.

    Comment


      #3
      Originally posted by ActionDave View Post
      AC unit is 120V?
      No it was a 5 ton 240 volt unit. The only 120 volt on the system would be at the air handler and normally their is a transformer to drop that down before the controller board.
      The 95% of people that you can't trust give the other 5% a bad name.

      Comment


        #4
        So according to the HVAC guy a lost neutral is frying a 240V motor on a piece of equipment that doesn't use a neutral?

        I'm not in a position to argue with anyone that is on site but I don't know about that.
        If Billy Idol is on your playlist go reevaluate your life.

        Comment


          #5
          When we have claims for this and it is deemed our fault (which is rare) it is always 120V appliances, TVs etc.
          NEVER paid a claim for a 240V appliance.

          Was it it just a bad connection at the weatherhead? Old aluminum split bolt connectors?

          Comment


            #6
            Originally posted by Hv&Lv View Post
            When we have claims for this and it is deemed our fault (which is rare) it is always 120V appliances, TVs etc.
            NEVER paid a claim for a 240V appliance.

            Was it it just a bad connection at the weatherhead? Old aluminum split bolt connectors?
            The bad neutral was caused by a tree limb rubbing the neutral conductor ( I guess as the wind blows). That's what the lineman that did the repairs said.

            We didn't have that much of a loss from appliances only a cable box. Before I left the TV and the microwave was back up and working. They were real lucky on that one. I shut power off as soon as I checked ( about 5 minutes ) and figured the problem was a bad neutral.

            The only thing I can't figure out is what happened to that AC unit. It just doesn't make sense. I have been reading a bit and that Lenox unit does have a more sophisticated control than a normal AC unit (because of the different speeds that the compressor can run). A friend of mine that's an HVAC contractor is supposed to go by and check it out and see if there are really $4K of repairs needed (estimated repair cost and that's just labor as the parts are under warranty ). He said it didn't sound right to him either.

            Other than the AC unit cost would be minimal and not worth worry about.

            I don't pretend to know everything but I have never seen an AC compressor (240 V circuit) damaged by a lost neutral.

            The 95% of people that you can't trust give the other 5% a bad name.

            Comment


              #7
              Originally posted by Hv&Lv View Post
              When we have claims for this and it is deemed our fault (which is rare) it is always 120V appliances, TVs etc.
              NEVER paid a claim for a 240V appliance.
              I don't think they would have much of a claim against the power company since trees on private property are the homeowner's responsibility . I'm not sure just how many homeowner's are aware of this. You see power lines running through trees all the time.

              The 95% of people that you can't trust give the other 5% a bad name.

              Comment


                #8
                Originally posted by growler View Post

                I don't think they would have much of a claim against the power company since trees on private property are the homeowner's responsibility . I'm not sure just how many homeowner's are aware of this. You see power lines running through trees all the time.
                AFAIK, the POCO is responsible up to the weather head, regardless of who owns the trees.

                Comment


                  #9
                  Originally posted by gadfly56 View Post

                  AFAIK, the POCO is responsible up to the weather head, regardless of who owns the trees.
                  +1
                  Its been awhile but when I was doing tree work around power lines POCO had a 20 ft right of way from the lines.
                  Sometimes I don't know whether I'm the boxer or the bag.

                  Comment


                    #10
                    Originally posted by growler View Post

                    I don't think they would have much of a claim against the power company since trees on private property are the homeowner's responsibility . I'm not sure just how many homeowner's are aware of this. You see power lines running through trees all the time.
                    Along the rights-of-way the POCO will come by and either prune a tunnel through the branches, remove half of the tree to avoid the wires, or remove the tree entirely. So the POCO does have some responsibility... at least up to the point where the homeowner's tap begins.

                    Comment


                      #11
                      Originally posted by gadfly56 View Post

                      AFAIK, the POCO is responsible up to the weather head, regardless of who owns the trees.
                      Nope. We don’t have right of way for secondary cables.
                      They are the customers trees.
                      I don’t know of a POCO around that could afford to cut trees for every secondary cable on their system.
                      Primary and transmission is different.

                      Comment


                        #12
                        Is the AC unit 120/240 by chance?
                        Our comedian shamelessly joked about a blackout. Talk about dark humor.

                        Comment


                          #13
                          Originally posted by mbrooke View Post
                          Is the AC unit 120/240 by chance?
                          No. 240 V.

                          That's what doesn't make sense.
                          The 95% of people that you can't trust give the other 5% a bad name.

                          Comment


                            #14
                            Originally posted by gadfly56 View Post

                            AFAIK, the POCO is responsible up to the weather head, regardless of who owns the trees.

                            The power company will repair their cable when damaged at no cost to the customer. But trying to get any damages out of them for damage done to appliances because of a lost neutral is another thing.

                            The 95% of people that you can't trust give the other 5% a bad name.

                            Comment


                              #15
                              Originally posted by growler View Post

                              No. 240 V.

                              That's what doesn't make sense.
                              Was just the neutral in the drop damaged or the phases? If a phase was intermittently open or shorting to neutral, the fluctuating L-L voltage could've kept stalling the compressor after it started.

                              More likely the fluctuating voltage at the 120 volt air handler was causing the AC contactor to keep dropping in and out.

                              Our comedian shamelessly joked about a blackout. Talk about dark humor.

                              Comment

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