Results 1 to 9 of 9
  1. #1
    Join Date
    Feb 2005
    Location
    sliema
    Age
    52
    Posts
    138
    Rep Power
    20

    Exclamation pipe lenght vis a vis oil traps



    Hey Guys,

    Yesterday vbeen on a hitachi HAS-12HNC.Found shorted compressor insulation !! Between the 5 indoors and the top roof level outdoor there are 7 storeys. There is not a single oil trap. Does not consider it normal . what are the views ? VRFs allowable to be a straight pipe or ? I cannot understand how the oil will be pulled up in that height back to compressor. Am I missing something ?



  2. #2
    Join Date
    Dec 2011
    Location
    England
    Age
    42
    Posts
    131
    Rep Power
    14

    Re: pipe lenght vis a vis oil traps

    I was always told, never trap a jap!! However, always follow the manufacturers instructions!!

  3. #3
    Join Date
    Feb 2007
    Location
    UK
    Posts
    2,479
    Rep Power
    45

    Re: pipe lenght vis a vis oil traps

    Always, always follow the manual. Or as we say over here RTFM.

    Although I believe all VRV/VRF manufacturers are the same, I can only tell you for certain how the Samsung kit works.
    No oil traps allowed regardless of rise or pipe length. The system will periodically enter what is known as "oil recovery". Basically the system open the indoor valves, raising the velocity of the refrigerant and pushing the oil back to the compressor.


  4. #4
    Join Date
    Oct 2007
    Location
    manchester
    Age
    50
    Posts
    5,707
    Rep Power
    45

    Re: pipe lenght vis a vis oil traps

    no oil traps,double risers,service valves onn any vrf as long as the install is within the design limitations then no issues

  5. #5
    Join Date
    Feb 2005
    Location
    sliema
    Age
    52
    Posts
    138
    Rep Power
    20

    Re: pipe lenght vis a vis oil traps

    Hi Guys,

    Thanks for replies. Yes actually that cannot insert oil traps in fancoils !! I mean the riser in my email. The riser is 7 storeys high and found system already there. I am trying to figure out prior to change compressor.

    Question is :

    The pipe work from Outdoor unit on roof goes down through a 7 storey shaft with no oil traps.Should there be one ?

  6. #6
    Join Date
    Feb 2007
    Location
    UK
    Posts
    2,479
    Rep Power
    45

    Re: pipe lenght vis a vis oil traps

    Short answer is "most likely not".

    Your best bet is to get hold of the installation manual for the system in question or call Hitachi.


  7. #7
    Join Date
    May 2014
    Location
    Bulgaria
    Age
    32
    Posts
    34
    Rep Power
    0

    Re: pipe lenght vis a vis oil traps

    I also confirm that most VRF systems do not need oil traps.

    There are enough oil recovery mechanisms installed in the outdoor unit, which seem to be well working at least in my installations.

  8. #8
    Join Date
    Aug 2012
    Location
    Russian Federation
    Posts
    17
    Rep Power
    0

    Thumbs up Re: pipe lenght vis a vis oil traps

    Quote Originally Posted by AC_From_Hell View Post
    I also confirm that most VRF systems do not need oil traps.

    There are enough oil recovery mechanisms installed in the outdoor unit, which seem to be well working at least in my installations.
    1. HITACHI RAS-12HNC very good airconditioner.

    2. But it is not VRF! It is Utopia Splits (RAS-12HNC - IVX standart)
    http://www.hitachiaircon.com/argws/en/ranges/utopia

    3. There is a function "oil recovery" or not in Utopia IVX standart - is unknown. In the service manual (SMGB0079 rev.0 - 01/2013) information is not available.

    4. IVX standart - maximum 4 indoor unit (IDU). IF 5 IDU - it is not good for oil return.


    kerrcell
    5. What is the total cooling capacity of indoor units?

    6. "Between the 5 indoors and the top roof level outdoor there are 7 storeys"
    7 storeys - how many meters of height difference ?

    7. Tell what position switches DIP DSW2 on PCB outdoor unit ?

    Best regards,
    Alex
    Last edited by AlexAlex; 25-04-2015 at 09:14 AM.

  9. #9
    Join Date
    Aug 2012
    Location
    Russian Federation
    Posts
    17
    Rep Power
    0

    Re: pipe lenght vis a vis oil traps

    deleted...
    Last edited by AlexAlex; 25-04-2015 at 08:56 AM.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •