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  1. #1
    Join Date
    Feb 2010
    Location
    Rhode Island
    Posts
    8

    Trane Voyager Issues

    I have been troubleshooting a "no heat" call on a Trane YCD061 rooftop unit and it seems I'm at a point where I need further assistance. This unit is equipped with a UCP and CTI board, both of which were replaced this past summer for problems with cooling. Now, during a call for heat from the programmable space thermostat, the unit will come on for about 10 seconds and then cycle off. Other times, when I jump out LTB 14 and LTB 5 to bypass the thermostat, nothing happens, but I do notice the green light on the IGN board is not lit. When I check the voltage at the TH+ terminal on the IGN board, I get 12 volts AC, not 24. I also get 12 volts AC at the J1-22 pin on the UCP but get 24 volts at the J1-21 pin (either side of the K6 contacts). It seems as thought I'm getting a voltage drop in the UCP board at the K6 contacts. But, when I unplug the cable at the IGN board and check the voltage at PPF3-2, I get 24 volts. I've checked both TC01 and TC02 and they're ok. If I take 24 volts right from the step-down transformer and apply it to TH+, the heat goes through a typical start sequence and lights off ok. The system runs ok when in the test mode.
    Very frustrating. Any help would be appreciated!

  2. #2
    Join Date
    Dec 2002
    Location
    SouthEast NC ICW & Piedmont Foothills
    Posts
    7,635
    1st- what are you using as the control a (conventional t-stat or a baysens)?

    2nd- why aren't you using the test feature?

    3rd-do you have the microcontrol manual?
    It`s better to be silent and thought the fool; than speak and remove all doubt.

  3. #3
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    18,593
    Speaking for myself, I want you to get Pro membership if you are a working pro, and post in the closed forums.

    It sounds as though an untrained person (or an unTraned person?) has been working on the unit, and things need to be checked in a methodical and professional manner, none of which can be imparted to you in an open forum on the site.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

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  4. #4
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,125
    Moved to tech to Tech commercial forum.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  5. #5
    Join Date
    Mar 2009
    Location
    Triad - North Carolina
    Posts
    333
    The first issue is jumping out terminals on a digital system. which terminals are which evade me as I'm not standing at it and looking at the diagram. It does have a set of "test terminals" at the top of that terminal strip that are meant to be "jumped out" by temporarily shorting or the installation of a resistor of the correctsize for you particular test.
    If you connect ( short ) the test terminals together the system will cycle through cooling and heating stages and you can remove the jumper when the heating cycle starts. this will tell you if the basic control functions are working at that point.
    Every problem gives us the opportunity to choose from several solutions: stupidity, ignorance, indifference, or brilliance. Which one will you choose?

  6. #6
    Join Date
    Feb 2010
    Location
    Rhode Island
    Posts
    8
    Thanks for replying, Keith. As I stated, I did run the unit through the test mode and the heat cycled normally. But that's where "normal" ended.

  7. #7
    Join Date
    Jan 2010
    Posts
    6,327
    So which stat do you have ?

  8. #8
    Join Date
    Feb 2010
    Location
    Rhode Island
    Posts
    8
    It's a Honeywell programmable. Not sure which model. It's wired between terminals LTB 14 and LTB 5. T-stat works ok.

  9. #9
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    18,593
    If you notice your original post was already moved to this forum so you didn't need to start a new thread

  10. #10
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    18,593
    Let me see if I have any info on this in the truck.

  11. #11
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    18,593
    LTB 14 and 5 should bring on your call for heat and jumping LTB 14 to LTB 7 should be your fan call.

    Are you a technician or the equipment owner?

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