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  1. #1
    Join Date
    Jul 2008
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    York rooftop with economizer

    So I will fully admit, I am a terrible tech when it comes to economizers, generally call tech support, they diagnose.
    Yesterday working working on a 2 stage compressor roof top, with economizer, it was 28c outside and damned if it would run in free cooling for like 10 minutes, then start 1st compressor, and control board giving me signal of compressor locked out do to free cooling, is this just a set up issue, for ambient temp, no manuals on site. If anyone has scene this before I would appreciate some advice. The economizer was full open, with 1st stage compressor on, I disconnected, the economizer motor linkage, and left economizer open 5% for now, because they were closing and had to leave.

  2. #2
    Join Date
    Nov 2006
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    Southeastern Pa
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    Model and serial please.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist
    Member, IAEI

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  3. #3
    Join Date
    Dec 2004
    Location
    Chicago area
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    Most likely an outdoor enthalpy or temp sensor error. Most enthalpy sensors require replacement every 3 to 5 years. But, regardless of that most OEM economizer set ups in the smaller RTU's are strait up garbage. Biggest issue is that you or anyone cant plainly see the information that they are processing (what it thinks the OA temp or enthalpy is, or what mode it is supposed to be in)
    You can probably get what is their corrected, but now days I usually push for an upgrade to Honeywell Jade control, or the Belimo set up that does the same thing. The wiring is simplified, and there is a display that can be navigated to plainly see what it sees.

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  5. #4
    Join Date
    Dec 2004
    Location
    Chicago area
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    Also, something to look for is impropper locations of the OA sensor, and inaccurate settings for the climate. I cant count how many times that I find the OA sensor located in the return air instead of the outside air. I always set economizers to the lowest possible enthalpy, or if possible 55F outside air, to limit humidity issues when running free cooling.

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  7. #5
    Join Date
    Jul 2008
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    Thread Starter
    York
    Zh090n15n5aaa5a
    N1m2303155

  8. #6
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    Jul 2008
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    Thread Starter
    I ordered the the outdoor sensor Friday, was a hunch, but actually took the sensor out of the unit, long leads stuck to the outside of the unit same issues, stuck outside cause the outside metal of unit a lot hotter than OEM placement, I appreciate your feedback heatingman, like I said, me and economizers not so good,

  9. #7
    Join Date
    May 2014
    Location
    Bay Area California
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    I haven't had any luck with Carrier or Trane tech support during the past two or few years, but York tech support has been superb.

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  11. #8
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    Jul 2008
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    Thread Starter
    I'm just really lost as to why 1st stage compressor kicking on, and free cooling in effect, there is no compressor crank case heaters on either compressor, y1 should be free cooling, and y2 be compressors, ambient temp sensor say it's to hot, turn on compressors. Unit has a logic board, maybe it's not set out properly since install, I'm really not sure. A world without DC controlled economizers would be the best, I need to be sent on a course😉 If your looking into reasoning behind issues heatingman, thnkyou

  12. #9
    Join Date
    Dec 2004
    Location
    Chicago area
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    If the unit thinks free cool is good to go, the Y1 = damper, and Y2 = first stage compressor only, not both. So what was happening is normal for an econ that thinks its okay to free cool.

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  14. #10
    Join Date
    May 2016
    Location
    Toronto, CAN
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    The unit is shooting for 55 deg f discharge air. It has 4 ways of doing it, econo only, econo & comp 1, comp 1 only, compressor 1&2. That unit would likely have a Honeywell 1042 in it. I have the bottom setting to D, to limit the usable range. Humidity is the issue here rather than sensible temp. There are time delays built in to stop it from moving the damper like a yoyo. You can download the pdf from Honeywell on the control which helps. More and more things are going to the jade control which is in some ways better, as it gives a display of what sensors are doing and what it's doing.

  15. #11
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    Mar 2008
    Location
    NC
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  16. #12
    Join Date
    Mar 2005
    Location
    Portland
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    Quote Originally Posted by BBeerme View Post
    I haven't had any luck with Carrier or Trane tech support during the past two or few years, but York tech support has been superb.
    well they should be.. they must be getting thousands of calls everyday..lol
    you will attract more flies with honey than with vinegar, but you can attract the most with a dead cat

  17. #13
    Join Date
    Jul 2008
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    Thread Starter
    Thank you for the Great video,ncboston, makes things a lot clearer,
    Thank you to all other posters as well, heading back to this job site tomorrow.

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