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Compressor Failed in Condensing Unit Twice in Two Years

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  • Compressor Failed in Condensing Unit Twice in Two Years

    We just had a second compressor on our walk in cooler fail in just over 2 years. It is 5 HP, 480 V, Copeland compressor. The condensing unit was purchased new and installed by a pro 2 years ago on our approximately 6000 cubic foot box.. The first/original compressor failed in February 2014, just about a year after purchase/installation. The second one just failed now, a little over a year after the first. The first was replaced under warranty but I am paying $2500+ for the new one now because the warranty is up (over a year).

    Over the past few weeks I noticed that the compressor sounded louder every time it ran. Some others thought I was imagining it so I didn't think too hard about it. Now I realize that was likely an early sign of it's demise.

    Any ideas what is going on? The refrigeration guy said the piping is correct and the lines have pressure and he did not think it was an oil issue. He speculated that it is something with our electrical service.

  • #2
    Is the chiller inside or outside? How much free space does the chiller have around itself?

    Have you used an ampmeter to see how many amps the compressor is pulling? Is it within spec? Does your compressor relay have a thermal overload relay? If so, is the little amp dial turned up all the way?

    You can always have the electric company install a recorder on your service panel to see if you are experiencing any voltage spikes and whether or not your harmonics are balanced. It may be nice to have a recorder installed for a month's time anyways to see how reliable your electrical service is.

    Is your BTU load in your cellar greater than your chiller's capacity? Do you have a remote glycol reservoir? Have you looked into whether you need to upsize the reservoir to help cut down on the number of times the compressor kicks on?

    Comment


    • #3
      Originally posted by NHBrewer23 View Post
      Is the chiller inside or outside? How much free space does the chiller have around itself?

      Have you used an ampmeter to see how many amps the compressor is pulling? Is it within spec? Does your compressor relay have a thermal overload relay? If so, is the little amp dial turned up all the way?

      You can always have the electric company install a recorder on your service panel to see if you are experiencing any voltage spikes and whether or not your harmonics are balanced. It may be nice to have a recorder installed for a month's time anyways to see how reliable your electrical service is.

      Is your BTU load in your cellar greater than your chiller's capacity? Do you have a remote glycol reservoir? Have you looked into whether you need to upsize the reservoir to help cut down on the number of times the compressor kicks on?
      The compressor is for a walk in cooler, not a chiller. It is inside, lots of free space around it. Not sure on any of the electrical stuff but I plan to talk to an electrician.

      Comment


      • #4
        This exact thing happened to us... we bought the walk-in cooling unit used and late last summer the compressor failed (after running for about 18 months). I replaced it, not knowing how old the original one might have been. Then about a month ago, the new replacement compressor failed. Our refrigeration tech speculated that it was also power related so we also installed a line monitor on the unit which will prevent it from coming back on if voltage is outside of tolerances... it also enforces a delay to prevent short cycling. Our unit is single phase, so the monitor was pretty cheap, for a 3ph unit, expect to pay a pretty penny but it will still be cheaper than replacing the compressor every year.

        I feel your pain, our unit has a huge receiver in it too, so filling it with new coolant is not cheap.

        Comment


        • #5
          On Premature Compressor Failures

          First thing. You need to start with a very savvy HVACR Tech rather than an Electrician to get at the root of the problem.
          Your system is misconfigured in some way and that will become apparent generally pretty quick in a case like this when someone who is versed in dealing with these matters lays hands on it.
          Warren Turner
          Industrial Engineering Technician
          HVACR-Electrical Systems Specialist
          Moab Brewery
          The Thought Police are Attempting to Suppress Free Speech and Sugar coat everything. This is both Cowardice and Treason given to their own kind.

          Comment


          • #6
            Originally posted by Starcat View Post
            First thing. You need to start with a very savvy HVACR Tech rather than an Electrician to get at the root of the problem.
            Your system is misconfigured in some way and that will become apparent generally pretty quick in a case like this when someone who is versed in dealing with these matters lays hands on it.
            +1000 on the above.
            Johnson Thermal Systems
            sales@johnsonthermal.com
            Johnsonthermal.com
            208.453.1000

            Comment


            • #7
              You don't mention if it's a 3-phase compressor, but, at 5 hp, I'll guess it is.

              We have had a couple of "events" where we lost several 3-phase motors/compressors at once over the years. One day a month ago, I was in the physical plant when all the 3-phase pumps that were not on VFDs started buzzing and stopped pumping. One leg of our 3-phase delta had gone down--the high leg, so it didn't affect any of our single-phase gear. This is almost certainly what has been killing our 3-phase motors, as, with one leg down, the motors just start producing heat and burn up.

              You can get and have installed a device called a "phase-monitoring relay". This will shut down the equipment if there is any variation between the three legs of a 3-phase system. I'm in the process of installing them on every piece of 3-phase equipment that isn't run off a VFD--which also monitors the phases.
              Last edited by TGTimm; 04-28-2015, 01:47 PM.
              Timm Turrentine

              Brewerywright,
              Terminal Gravity Brewing,
              Enterprise. Oregon.

              Comment


              • #8
                The piping/system could be contaminated as a result of an incorrect installation or pump replacement procedure. I've seen this happen even with 'professional' techs. Was the system flushed/filter driers replaced after the first install? Was the original cause of failure ever determined?

                Like mentioned, your best bet is to get a good tech to come in.


                Best of luck.

                Comment


                • #9
                  Down the list

                  This is an ICM 408C line side phase protector similar to what Timm has referred to:



                  They do a good job at protecting for single phase faults on the incoming line only and are definitely worth the expense which is not much for what they do. Installing them correctly on various machines takes some expertise with how said machine are controlled and then they have to be set correctly. The main tenet is to stop single phase faults while having things contoured to avoid nuisance trips. This model is a pilot duty device that must be integrated into the control circuit harmoniously, in some cases requiring an extra relay and so forth.

                  There are MANY chiller systems out there at large that are set up wrong from the get go as in hacked six ways to Sunday and never gone through by a highly trained and experienced chiller tech who can " debug " the TOTAL INSTALL.

                  There are myriad causes for early failure and having several failures and changeouts can create new problems down the line such as contamination and oil logging etc.
                  Just by what has been stated about the progressive sound of the compressor its possible to venture from a distance that one of several things may be going on. These are possibilities:
                  Floodback condition recurring.
                  Flooded starts
                  Overload condition.
                  Off cycle migration
                  Short cycling

                  Improper control configuration.
                  Improper control settings.

                  These are a few things that come to mind.
                  Warren Turner
                  Industrial Engineering Technician
                  HVACR-Electrical Systems Specialist
                  Moab Brewery
                  The Thought Police are Attempting to Suppress Free Speech and Sugar coat everything. This is both Cowardice and Treason given to their own kind.

                  Comment

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