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  1. #1
    Join Date
    Dec 2009
    Location
    TN & MS
    Posts
    60

    R134a vs POE oil

    Question regarding R134a vs POE oil.... Which is heavier? I have a 23xrv machine, 450 tons, with the following:
    Cooler-
    EWT- 60.2
    LWT- 50.7
    Refrigerant temp- 39.7

    Condenser-
    EWT- 80.6
    LWT- 92.2
    Refrigerant temp- 97.2

    % amps- 94%

    With the machine operating, the evap and condenser refrigerant temps match on the PT chart the correct pressures, and transducers and thermistors are correct (verified with gauges). We have shut the machine down and have noticed that the evap refrigerant temp will show a different temp than the EWT and LWT. Ex: EWT and LWT of 71 degrees F, Evap temp of 51 degrees F. This will slowly rise during the day. The thought is the thermistor that reads the evap temp is on the bottom of the cooler, oil Is logged there,therefore we are getting the high split between the water temps and the refrigerant temp with the machine off.

    My concerns are (1) is oil lighter or heavier than the refrigerant, and (2) the readings line up with the machine running, yet we still have a high evap approach, is this a low refrigerant issue?

    Waiting at this point to get some feedback from our higher ups at our shop on what they want done next, but I wanted to share and get some different inputs on what could be the issue/ issues.

    I apologize for any thing left off this, if more information is needed, please ask.

    Thanks and have a great day!!
    "The race is to the driven....not the swift."

  2. #2
    Join Date
    Mar 2004
    Location
    ottawa canada
    Posts
    1,847
    How are the water flows compared to design and when were the tubes last cleaned ?
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
    You bend em" I"ll mend em" !!!!!!!
    I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
    Best Austin Healey In Show twice in 2013 .....All those hrs paid off .

  3. #3
    Join Date
    Dec 2009
    Location
    TN & MS
    Posts
    60
    Tubes cleaned 2 weeks ago. We are close to design flows but not exactly there. Design 11.6 on the cooler pressure drop and 12.6 for condenser. We are around 12 to 14 respectively.

    Thank you!
    "The race is to the driven....not the swift."

  4. #4
    Join Date
    Mar 2004
    Location
    ottawa canada
    Posts
    1,847
    Quote Originally Posted by ColdAirMan View Post
    Tubes cleaned 2 weeks ago. We are close to design flows but not exactly there. Design 11.6 on the cooler pressure drop and 12.6 for condenser. We are around 12 to 14 respectively.

    Thank you!
    Condenser and evaporater ?
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
    You bend em" I"ll mend em" !!!!!!!
    I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
    Best Austin Healey In Show twice in 2013 .....All those hrs paid off .

  5. #5
    Join Date
    Dec 2009
    Location
    TN & MS
    Posts
    60
    Quote Originally Posted by Healey Nut View Post
    Condenser and evaporater ?
    Both evap and condenser tubes brushed.
    "The race is to the driven....not the swift."

  6. #6
    Join Date
    Dec 2009
    Location
    TN & MS
    Posts
    60
    Update: started to pull liquid R-134a out the chiller to get oil out and to distill, weigh the charge back in as vapor to see how much oil was in the system. Seems we have a leak in the system or the shop that had this machine before shorted the charge after checking the integrity of the muffler. Will keep updating as this job goes on. Thanks for the inputs!
    "The race is to the driven....not the swift."

  7. #7
    Join Date
    Jun 2012
    Location
    Los Angeles, California
    Posts
    37
    You could of mentioned something about discharge temp. If this chiller was oil logged, it would have been carrying over, and would of showed as low discharge superheat. Good way to tell if it's the charge or oil logged. If the chiller is low on charge than more than likely the sensor is out of the liquid. Oil would read the same.

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