Page 1 of 2 12 LastLast
Results 1 to 13 of 20

Thread: carrier RTU

  1. #1
    Join Date
    Apr 2010
    Location
    Southeast
    Posts
    40

    carrier RTU

    Any thoughts on disabling the algorithm on a comfort link for the condensing fan motor?? Why didn't they just add a high pressure transducer to turn it on..

  2. #2
    Join Date
    Jul 2006
    Location
    Anytown USA
    Posts
    2,055
    Why would you want to do that?

    i know the condenser thermisters always fail, but thats no reason to change something from OEM.

  3. #3
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,702
    Makes me wonder what your talking about , I'm thinking there is a bit more to this.
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  4. #4
    Join Date
    Sep 2007
    Location
    NH
    Posts
    1,136
    I find most of the thermisters mounting clips break causing them to not be on the u bend... Just throw a tie wrap around them and they work fine....

    I have found 2 fail open though.
    Last edited by Dchappa21; 04-25-2010 at 05:18 PM. Reason: thermisters not transducers duh

  5. #5
    Join Date
    Apr 2010
    Location
    Southeast
    Posts
    40
    There always is more to the story....It is controlled by an ems system and they decided to not run some of the units to save power. It is only a problem in low ambient conditions and with first stage. The failure of the thermisters has a different error code and I have replaced a few in the past too. This is a different failure. You can watch the readings and see that the thermister is fine and of course ohm them out. Mounting I agree is of course a issue and this is not a problem. The error happens only after the unit first starts then after that does not have any problems. I am just a tech not a engineer but a transducer make so much more sense...Thanks for you comments.

  6. #6
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,702
    Quote Originally Posted by ccservicefitter View Post
    It is controlled by an ems system and they decided to not run some of the units to save power. It is only a problem in low ambient conditions and with first stage. So for the mean time I wired the first fan motor contactor to the first stage contactor. I like the idea of placing the thermister on the u bend of the coil. It will work just fine however a transducer make so much more sense...Thanks for you comments.
    What's the model of roof top you working on?
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  7. #7
    Join Date
    Dec 2004
    Location
    Brooklyn, New York
    Posts
    170
    is carrier moving away from motor master fan control?

  8. #8
    Join Date
    Apr 2010
    Location
    Southeast
    Posts
    40
    I don't have the model number, it was on a Target store. Carrier has that special relationship with Target. The model is particular to Target according to Carrier, I talked to a Carrier engineer and he said he would get back to me on this. Well that was like 2 months ago.

  9. #9
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,702
    Quote Originally Posted by ccservicefitter View Post
    I don't have the model number, it was on a Target store. Carrier has that special relationship with Target. The model is particular to Target according to Carrier, I talked to a Carrier engineer and he said he would get back to me on this. Well that was like 2 months ago.
    Ah now that were kinda know what we are working on ? Why is the unit not economizing? Is your enthalphy switch working correctly? The HG's are pretty good unit's I bet it doesn't even have a motormaster on it . You might want to insulate the current sensor to see if that helps.
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  10. #10
    Join Date
    Jul 2006
    Location
    Anytown USA
    Posts
    2,055
    So what is the exact problem you're having? You said something about an error code during low ambient conditions, What error code are you talking about?

  11. #11
    Join Date
    Apr 2010
    Location
    Southeast
    Posts
    40
    Good point listener. High humidity in my neck of the woods for the economizer. No motormaster on this unit.
    Turbo-high head pressure is the error, I don't remember the exact error #. I know the error # is different for a failed thermister.

  12. #12
    Join Date
    Jul 2006
    Location
    Anytown USA
    Posts
    2,055
    Quote Originally Posted by ccservicefitter View Post
    Good point listener. High humidity in my neck of the woods for the economizer. No motormaster on this unit.
    Turbo-high head pressure is the error, I don't remember the exact error #. I know the error # is different for a failed thermister.

    Take the panels off where the thermisters are. I just found 5 of them broken with no error codes on the comfort link panel at 1 retail store. They would still read temperature, and would bring on the fans but late. I think they were sensing the heat generated by the coil but they were not directly sensing the coil temperature.

    Now every unit I work on with those condenser thermisters, I take the panels off to check the sensor. You would be surprised on how many I find with broken clips and are just hanging next to the coil.

    Anyway, I dont know if that helps, but its something to look into.

    good luck.

  13. #13
    Join Date
    Apr 2010
    Location
    Southeast
    Posts
    40
    Turbo- I will look into it thanks for your help

Page 1 of 2 12 LastLast

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