Results 1 to 8 of 8
  1. #1
    Join Date
    Jun 2019
    Posts
    7
    Post Likes

    RTAA200 error 198 (low oil flow compressor A)

    Am working on Trane RTAA200 machine. Got code 198 low oil flow compressor A. Read on this web site it is due to condenser clogged or bad condenser fan motor. I do indeed have a whole bank of motors not running due to a blown fuse. Not sure why it went off on oil failure instead of high pressure. Found and fixed problem just trying to understand why that alarm is contributed to bad fans? Thank you

  2. #2
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    3,517
    Post Likes
    Head pressure is the driving force for oil flow. Increased head means increased flow. Increased flow results in increased pressure drops in the oil circuit, including across the oil filter. If head pressure is abnormally high enough, the pressure drop can reach the trip point.
    In honor of RichardL: "Ain't 'None' of us as smart as 'All' of us".

  3. #3
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    3,517
    Post Likes
    Quote Originally Posted by Nuclrchiller View Post
    Head pressure is the driving force for oil flow. Increased head means increased flow. Increased flow results in increased pressure drops in the oil circuit, including across the oil filter. If head pressure is abnormally high enough, the pressure drop can reach the trip point.
    To add to this, the reason your chiller did not trip due to high head is that the chiller can tolerate abnormally high head pressure better than it can low oil flow. So the trip setting for "low oil flow" (which is actually oil filter differential pressure) has a tighter tolerance with respect to normal oil flow (filter diff. pressure), compared to a greater tolerance for high head pressure. Since the same sensor circuit is used for for both protections, is not unusual to see "low oil flow" trips when abnormally high head pressure conditions exist (dirty coils, bad fan motors, etc.).
    In honor of RichardL: "Ain't 'None' of us as smart as 'All' of us".

  4. Likes manny238 liked this post
  5. #4
    Join Date
    Jun 2019
    Posts
    7
    Post Likes
    Thread Starter
    That actually kinda makes sense. Thank you

  6. #5
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    3,517
    Post Likes
    Quote Originally Posted by Mhunter929 View Post
    That actually kinda makes sense. Thank you
    You're welcome.

    And welcome to the site!
    In honor of RichardL: "Ain't 'None' of us as smart as 'All' of us".

  7. #6
    Join Date
    Apr 2018
    Posts
    68
    Post Likes
    Check differential pressure switch in compressor terminal cover. Factory set to 50psid. Measures differential across oil filter. You check pressure on both sides. May be an issue with the switch oil could be clogged oil filter.

  8. #7
    Join Date
    Jul 2018
    Location
    Kazakhstan
    Posts
    23
    Post Likes
    Mhunter929, some useful info you may find in Trane service bulletin SB-12. Troubleshooting high pressure cutout and low oil flow diagnostics on RTAA 130-400 ton chillers.

  9. #8
    Join Date
    Nov 2004
    Location
    up in the hizzy
    Posts
    3,338
    Post Likes
    Quote Originally Posted by Sserrviceman View Post
    Mhunter929, some useful info you may find in Trane service bulletin SB-12. Troubleshooting high pressure cutout and low oil flow diagnostics on RTAA 130-400 ton chillers.
    Way to go
    Attached Thumbnails Attached Thumbnails index.jpg  
    There is not better place for the working men than the union! 100% UA the only HVAC union!

Posting Permissions

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