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    why would Compressor vibrate? (20 Posts)

  • elfie elfie @ 11:13 AM
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    why would Compressor vibrate?

    what would cause a compressor to vibrate excessively?

    this is a large compressor for a 20 ton system.

    thanks
  • Spence Spence @ 11:58 AM
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    Vibration

    Some manufacturers put large compressors on springs. If this is your case, after hundreds of hours of operation, a spring or springs can break, throwing the compressor off-balance. Kits are available for replacement.
  • elfie elfie @ 12:34 PM
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    vibration -bearings?

    could it be a sign that bearings are a problem?

    have been told bearings are a problem - how is this diagnosed?
  • Spence Spence @ 5:36 PM
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    Bearings

    Do you have a hermetic (sealed) compressor, or a semi-hermetic (looks like a small car engine)?
  • Spence Spence @ 5:45 PM
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    Bearing Check

    Attach your gauges to see their readings as compared to the factory charts. Under operation, measure the compressor amps on the COMMON lead. Compare your amps to the nameplate. If your vibration is not a broken mounting spring and your amp reading is 15% or more above the nameplate, that would certainly indicate damaged bearings.
  • Spence Spence @ 5:56 PM
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    Vibration

    If this is a start-up and you have a scroll compressor, it might be running in reverse. If this is the case, switch around the power legs at the disconnect until it quiets down and your pressures look normal, or if you have a phase monitor, the LED will be green when it is happy.
  • Techman Techman @ 6:22 PM
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    vIbRaTeeInG CoMp.

    What comp style? How old? AC? New problem or existing? Compressor oil sight glass? Press/temps? Amps? You hear it? You feel it? You see it? You sense it, Grasshopper !? It could be a broken TXV thermal bulb strap .It could be...............!
    This post was edited by an admin on June 21, 2013 6:31 PM.
  • RJ RJ @ 12:49 PM
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    vibration

    pretty sure from last post it is a carlyle ( made for carrier equip.) semi hermetic.  probably worn bearings or crankshaft, you can pull the heads and look at the pistons.( dont do this unless you have experience in compessor teardown ).  chances are if the vibration is extreme you will need to replace compressor.  than find the cause ( liquid refrig or oil slug ? )
    RJ
  • elfie elfie @ 2:59 PM
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    a carlyle compressor faced with liquid slugging

    i guess if you have freon that has not fully evaporated returning back to the compressor it could lead to compressor problems like vibrations.  (i.e liquid slugging damaginh pistons and cause bearing problems which causes vibration, etc)

    there has been chronic foaminess in the oil sight glass, and its likely air flow through coils/ventilation system is not adequate (which causes freon to not fully evaporate)

    does all this make sense

    thanks
  • RJ RJ @ 5:24 PM
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    vibration

    sounds like liquid in the crankcase.   check your air side , get a fan curve for the ahu, get some air side readings,  check refrig piping sizes, dont put in another compressor until you check these.
    RJ
  • Techman Techman @ 5:55 PM
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    Oil sight glass

    That foaming in the glass could be, excess oil in the crankcase or maybe a massive "flood back" to the comp, testing SH @comp & TXV will help. Press/Temps? Indoor/Outdoor temps? How old?
  • elfie elfie @ 6:25 PM
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    compressor age

    compressor fort his 22 ton Carrier system was rebuilt in 2000 but is used infrequently (3-4 hrs per week)

    its got a long freon run (about 200 feet) so that seems to cause oil pressure problems which tend to shut down unit after a few minutes (and leads to jumping to bypass oil pressure controls)

    its my belief that a Carrier certified rep (hopefully with best knowledge of compressors and systems) may be best to take a look
  • Techman Techman @ 7:44 PM
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    Comp

    Now NO OFFENCE TO ANYONE !!!!!!! Rebuilt vs. remanufactured !?  Reman is the only way to go! There is a LiquidLineSolenoidValve ? Where in the LL is the LLSV? There is a CrankCaseHeater? And the CCH is hot for those 152 hrs. a week the comp is idle? After being off for 2-3 days  start the system and have press instruments to ck the oil/crankcase/low side press.
  • RJ RJ @ 9:19 PM
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    vibration

    A few questions   what are your line sizes,   how much horizontal pipe, how much vertical pipe. how many 90s.   Is there an unloader on compressor,  If you have a 40RM style AHU what size are your TXVs,  do you have cond. fan cycling, is your crankcase heater operational. is your AHU blower rpm set to match what your fan curve is calling for.
    RJ
  • Spence Spence @ 9:02 AM
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    Oil Foaming

    Again, check pressures and amp draw against nameplate. Sounds as if you're running hot has anyone checked, really checked, the condenser coil?
  • unclejohn unclejohn @ 6:51 PM
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    Put your hand

    On the oil pump after the unit has run for 20 mins or so. If its cold you have flood back. It should be warm. If cold put your hand on the heads of the compressor. 20 ton should be a three header. One or more of the heads may have a unloader. Make sure the compressor is fully loaded. One side of all heads should be cool the other very hot. The ones that are all hot have broken valves and a new valve plate should do the trick and then address the flood back problem.
  • RJ RJ @ 7:22 PM
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    vibration

    I agree with part of the hands on diagnosis, but bad valves themselves would not cause extreme vibration in a semihermetic compressor, they are although a symptom of liquid floodback, maybe time to get a second set of eyes on this job, preferably someone with exp. in semihermetic and open drive compressors. It might be time to reclaim the refrig. and get any liquid out of the crank than see if you still have vibration
    RJ
  • Techman Techman @ 8:01 AM
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    vibrate

    Start the system and test the SH @ evap and @the comp Do the comp test 1st. Then you know right away if the SH is proper or not. Check the 3 pressures all at the same time, oil pump press , suction line press and the crankcase press. Do a hi side reading also.
  • elfie elfie @ 1:02 PM
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    pic of compressor

    fyi,   here is a pic of the carlyle compressor
  • Techman Techman @ 10:45 PM
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    Looks nice.

     Now don't go &  get this wrong OK . Looking Pretty don't mean squat if you're not working right! As an apprentis  , there was an AC cond unit in , what was called "Pigeon Ship Alley" , looked HORRIBLE , but it ran and the customer was happy. You had to beep the horn a bunch of times , A BUNCH OF TIMES to clear out the alley before venturing out into THEIR territory . Rain coats optional!!!!!!!!!!!!!!!

    So a few readings go a looooooooooooooong way!
    This post was edited by an admin on June 24, 2013 10:56 PM.
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