Page 2 of 2 FirstFirst 12
Results 14 to 25 of 25

Thread: Carrier RTU

  1. #14
    Join Date
    Nov 2009
    Location
    Bismarck ND
    Posts
    86
    Found belt broken causing y2 to call and bring on mechanical. Thinking about adding an outdoor lockout to stop mechanical cooling from coming on as the compressor were a huge block if ice

  2. #15
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    18,549
    Quote Originally Posted by HVACTECHND View Post
    Found belt broken causing y2 to call and bring on mechanical. Thinking about adding an outdoor lockout to stop mechanical cooling from coming on as the compressor were a huge block if ice
    Many units use a low pressure safety, too.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







  3. #16
    Join Date
    Sep 2007
    Location
    NH
    Posts
    1,150
    Or a freeze stat.

  4. #17
    Join Date
    Feb 2006
    Location
    USA
    Posts
    4,381
    Quote Originally Posted by timebuilder View Post
    That is possible. A lot of guys have no interest in learning how an economizer works, or how to troubleshoot it.
    So true. Economizers have kept me very busy during the winter over the years. On many new accounts I often find enthalpy sensors disconnected with nothing else wrong. I tell young guys to learn about them because they generate work for the cold months when some get slow. I urge guys to not look at the controller and get overwhelmed. I tell them to break each circuit down and things get much less complicated. That is of course once they get an understanding of them

    Sent from my SGH-T999 using Tapatalk 2

  5. #18
    Join Date
    Feb 2006
    Location
    USA
    Posts
    4,381
    Quote Originally Posted by Dchappa21 View Post
    Or a freeze stat.
    That was my initial thought . .

    Sent from my SGH-T999 using Tapatalk 2

  6. #19
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    18,549
    Quote Originally Posted by Dchappa21 View Post
    Or a freeze stat.

    Also a good idea to have that in the chain. We also install a low ambient control for those Y2 calls on cooler days.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







  7. #20
    Join Date
    Mar 2012
    Location
    Georgia
    Posts
    21
    Economizer would disable 1st stage mechanical cooling if outdoor conditions were suitable (sounds like they are) for free cooling. Suction line freeze stat on 2nd stage compressor or Low ambient thermostat for 2nd stage lockout. These units are not designed to protect the compressors from ANY unit malfunction.
    Last edited by Cold shot; 12-31-2012 at 05:15 PM. Reason: incorrectly described the product that was being talked about.

  8. #21
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    18,549
    I can't say that I know of any design that "protects the compressors from any unit malfunction....."
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







  9. #22
    Join Date
    Mar 2012
    Location
    Georgia
    Posts
    21
    True, but there are several things that can be added. Air proving switch, freeze stat, low & high pressure switches, discharge line thermostats, phase monitors. All to protect the compressor.

  10. #23
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    18,549
    Quote Originally Posted by Cold shot View Post
    True, but there are several things that can be added. Air proving switch, freeze stat, low & high pressure switches, discharge line thermostats, phase monitors. All to protect the compressor.
    I'll go with that. You can protect the compressors from SOME malfunctions.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







  11. #24
    Join Date
    Feb 2005
    Location
    In a van by the river
    Posts
    621
    Quote Originally Posted by Cold shot View Post
    Economizer would disable 1st stage mechanical cooling if outdoor conditions were suitable (sounds like they are) for free cooling. Suction line freeze stat on 2nd stage compressor or Low ambient thermostat for 2nd stage lockout. These units are not designed to protect the compressors from ANY unit malfunction.
    Just to prevent any confusion, when second stage cooling is energized while a system is economizing, first stage compressor energizes and comes on (compressor 1 and not compressor 2)
    ## + years in the field never made you a know-it-all This industry is far more diverse than you are

  12. #25
    Join Date
    Jan 2010
    Posts
    6,297
    I always shake my head when I see a economizer installed but never hooked up.

Page 2 of 2 FirstFirst 12

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