Results 1 to 8 of 8
  1. #1
    Join Date
    Dec 2003
    Location
    Kenilworth New Jersey
    Posts
    230

    Honeywell W7900 won`t shut off

    We have a W7900 in a Trane air cooled recip chiller with 2 Model R compressors set up for 6 stages of cooling. The 6 stages are set on a dial on face of the controller itself, not a resister like the W7100 uses. We are running a 30% propylene glycol solution. Problem is as setpoint is approached and passed the last stage of cooling does not shutdown and the temp just keeps dropping. Our mechanic replaced the controller with a used one we had laying around and it does the same thing, the LCW sensor was ohmed out and tests good. Any ideas? Sorry about not having the chiller model #. Thanks for any input.

  2. #2
    Join Date
    Jun 2008
    Location
    Windsor, Ont.
    Posts
    490
    I can't even find a w7900 on Honeywell's website, it's likely OEM to Trane the only info I can find is at the link.

    http://members.cox.net/epittman2/hva...CGWC-SB-2A.pdf

  3. #3
    Join Date
    Dec 2003
    Location
    Kenilworth New Jersey
    Posts
    230
    Looks like you`re right and Thanks

  4. #4
    Join Date
    Jun 2009
    Location
    StL, MO
    Posts
    581
    Quote Originally Posted by h2045 View Post
    ...Our mechanic replaced the controller with a used one we had laying around and it does the same thing...
    Can we guess why the used one was lying about?

    The problem you are seeing is probably an internal issue to the W7900. We've been replacing, retrofitting actually, these regularly over the past couple of years.
    UA LU 562

  5. #5
    Join Date
    Dec 2003
    Location
    Kenilworth New Jersey
    Posts
    230
    The problem you are seeing is probably an internal issue to the W7900. We've been replacing, retrofitting actually, these regularly over the past couple of years.
    What are you using as a retrofit?

  6. #6
    Join Date
    Jun 2009
    Location
    StL, MO
    Posts
    581
    Johnson FX07.
    UA LU 562

  7. #7
    Join Date
    Jun 2008
    Location
    Florida (Sharpes)
    Posts
    16
    H2045
    So you have and obsolete Honeywell 7900. I have had to up-grade five of them in the last three years. I have used the MSC Magnum. The controller is a chiller control so you get all of the fuzzy logic needed to try to keep the chiller running. It has worked out as an excellent recontrol of the chiller and made for a happy owner. My e-mail address is in my profile if you would like more info.
    Robert1078

  8. #8
    Join Date
    Apr 2009
    Location
    In the south
    Posts
    30
    You can use a Trane TOL101 to check out a w7900. Comes with all connections and instructions for checking it out

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event