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  1. #1
    Join Date
    Aug 2008
    Posts
    9

    Trane 2 stage heat proper operation?

    This past summer I had a complete Trane system installed. I got the XL15i 2.5 ton A/C unit and a XV95 furnace, which is a 2 stage variable speed furnace.

    I was told, that the way the heat would work is that the system would kick on at a low blower speed (50%?) and only kick to full blower speed and BTU's if it was not able to keep up. I was told that I would basically have a steady very quiet and slow stream of warm air out the registers.

    This morning, the 2nd time the heat kicked on (after an earlier on period that warmed it to the programmed temp), it just seemed to blow normal like when the AC was on completely. When the AC unit would kick off outside, the blower would run at probably 50% for a couple minutes - this is what I expected the initial on period of the heat to be.

    What should be happening?

    Thanks,
    Matt




    Here are the settings for the system...

    First the Dip switches on the board...
    1 - off
    2 - on
    3 - off
    4 - off

    5 - on
    6 - on
    7 - off
    8 - on

    Wires attached to board Left to Right...
    BK - Nothing
    W2 - Brown
    W1 - white
    R - White (thick white wire - power?)
    G - Green
    B/C - 2 Blue
    Y - 2 Yellow
    YLO - Nothing
    O - Nothing

    T-Stat settings (TCONT-802) that I think are relevant
    0170 - 9 (2 Heat / 1 Cool)
    0240 - 3 (3cph used for 2 stage fossil fuel forced air systems)
    0350 - 3 (3cph used for 2 stage fossil fuel forced air systems)

    T-Stat wires: (Using Inner Heat/Cool letters)
    RC, R are jumpered together with Red wire attached to R
    W1 - White
    Y - Yellow
    G - Green
    B - Blue
    W2 - Brown

    I also have a Outdoor temp sensor (S1/S2) for display only with a separate 18-2 wire run for that.

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,704
    0170 is set wrong.

    9 is for a 2 stage furnace.
    Not a dual fuel set up.
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  3. #3
    Join Date
    Feb 2008
    Location
    Waffleville
    Posts
    10,339
    i thought the XV95 was three stage
    If Guns Kill People, Do Pencils Misspell Words?

    http://www.youtube.com/watch?v=An2a1...eature=related

    Before we work on artificial intelligence why don't we do something about natural stupidity?

  4. #4
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Quote Originally Posted by beachtech View Post
    i thought the XV95 was three stage
    Nope, XC95 is 3 stage.

  5. #5
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Quote Originally Posted by beenthere View Post
    0170 is set wrong.

    9 is for a 2 stage furnace.
    Not a dual fuel set up.
    Been, he does have 170 set to 9

  6. #6
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,704
    Quote Originally Posted by mayguy View Post
    Been, he does have 170 set to 9
    I thought he said he has a heat pump and 2 stage furnace.
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  7. #7
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Quote Originally Posted by mattg View Post
    I was told, that the way the heat would work is that the system would kick on at a low blower speed (50%?) and only kick to full blower speed and BTU's if it was not able to keep up. I was told that I would basically have a steady very quiet and slow stream of warm air out the registers.
    If the temp setting was left alone all the times, yes the furnace will run 1st stage most of the time.

    This morning, the 2nd time the heat kicked on (after an earlier on period that warmed it to the programmed temp), it just seemed to blow normal like when the AC was on completely.
    In Recovery mode, the thermostat is going to put the furnace into 2nd stage to help recover from set point.

    When the AC unit would kick off outside, the blower would run at probably 50% for a couple minutes - this is what I expected the initial on period of the heat to be.
    After the burners goes out, the blower will run for about 90sec (depends on what it is set at the control), to cool down the heat exchanger then it will shut down.



    Wires attached to board Left to Right...
    Y - 2 Yellow
    O - Nothing
    Looks like a jumper was not added to get the full "Comfort-R" profile.

  8. #8
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Quote Originally Posted by beenthere View Post
    I thought he said he has a heat pump and 2 stage furnace.
    Maybe beddy time for you? :-)

    Quote Originally Posted by mattg View Post
    I got the XL15i 2.5 ton A/C unit and a XV95 furnace, which is a 2 stage variable speed furnace.

  9. #9
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,704
    Quote Originally Posted by mayguy View Post
    Maybe beddy time for you? :-)
    I saw that after I read it for the third time.
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  10. #10
    Join Date
    Aug 2008
    Posts
    9
    To clear up a couple things...

    No, it is not a dual fuel. The outdoor XL15i is A/C only. Heat it totally controlled by the XV95 furnace.

    I plan to bring this up when they come out for my fall service visit. I am trying to educate myself on the setup before they get here so I can ask the right questions.

    Additionally, 2 thicker white wires come into the furnace from the water sensor in the pan on the floor. One of those goes to the board, and the other is tied into the red wire from the t-stat.


    Quote Originally Posted by mayguy View Post
    If the temp setting was left alone all the times, yes the furnace will run 1st stage most of the time.
    In the limited amount of times it has kicked on, I have only noticed 1 stage, which to me, sounds (like I said) just like the AC stage sounded.


    In Recovery mode, the thermostat is going to put the furnace into 2nd stage to help recover from set point.
    I assume you mean that when the program kicks from 65 to 68 as "recovery Mode". I noticed what I believe is full on blower mode when it already was at 68 and was maintaining temp.


    [QUOTE]After the burners goes out, the blower will run for about 90sec (depends on what it is set at the control), to cool down the heat exchanger then it will shut down.[QUOTE]

    When the AC was in operation, it would kick to a slower blower spead when the outdoor unit turned off, and run for a set period of time. I noticed no such slowdown for the heat.




    Looks like a jumper was not added to get the full "Comfort-R" profile.
    I am looking at the installers guide for a 2 stage heat / 1 stage cool. There is a note about jumpers:

    "Optional humidistat is to be connected between "R" and "BK". Factory Installed jumper "R" to "BK" on the circuit board must be cut if optional humidistat is used. The jumper must also be cut when applying an Airflow command signal to the "BK" input such as with the variable speed single-zone and multi-zone system controllers. On single speed cooling only / Non-heat pump systems, Jumper "Y" to "O" for proper operation of the delay profiles and the humidistat. For two compressor or two speed systems, jumper "YLO" to "O".

    Is this what you are referring to?

    I also notice that the dip switches 5 and 6 have something to do with Comfort-R. Is Comfort-R the setting in which the t-stat controls the stages?

    Would this missing jumper affect anything on the cooling side as well?


    Thanks

  11. #11
    Join Date
    Aug 2008
    Posts
    9
    OK.

    I just did a test.

    It was 71 in the house (still warm during the day here) and I set the t-stat to 70. I then opened the windows and turned on a fan in a nearby bedroom. Outside temp is 46.

    Temp got to 70, and then eventually kicked the heat on. I then ramped up the temp to 75, and after about 10 seconds, it did get noticeably louder at the return, so it does appear to be giving me two stage... Does the O and Y still need jumpered? Does it make sense to work the way I described without the jumper?

    I also notice that there seems to be 3 different blower speeds.

    1 - Very low, used after the outdoor AC unit shuts down for a period of maybe a min or 2.

    2 - Initial heat mode

    3 - Very fast heat when I ramp up the set temp.


    I guess I was expecting the very slow (1) setting for the initial heat setting.

    Still curious to get more info on the missing jumper... what exactly does that give me?

    What is the "Full" Comfort-R profile VS what I am set for.

  12. #12
    Join Date
    Jun 2008
    Posts
    72
    I just read MayGuy's reply here regard to Comfort-R
    http://hvac-talk.com/vbb/showpost.ph...0&postcount=55
    "Comfort-R is only in A/C mode."

    I hope I quote him correctly. Because I was under the impression Comfort-R is also heat guess not.


    Quote Originally Posted by mattg View Post
    OK.

    I just did a test.

    It was 71 in the house (still warm during the day here) and I set the t-stat to 70. I then opened the windows and turned on a fan in a nearby bedroom. Outside temp is 46.

    Temp got to 70, and then eventually kicked the heat on. I then ramped up the temp to 75, and after about 10 seconds, it did get noticeably louder at the return, so it does appear to be giving me two stage... Does the O and Y still need jumpered? Does it make sense to work the way I described without the jumper?

    I also notice that there seems to be 3 different blower speeds.

    1 - Very low, used after the outdoor AC unit shuts down for a period of maybe a min or 2.

    2 - Initial heat mode

    3 - Very fast heat when I ramp up the set temp.


    I guess I was expecting the very slow (1) setting for the initial heat setting.

    Still curious to get more info on the missing jumper... what exactly does that give me?

    What is the "Full" Comfort-R profile VS what I am set for.

  13. #13
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Quote Originally Posted by Ohouse View Post
    I hope I quote him correctly. Because I was under the impression Comfort-R is also heat guess not.
    It can be for heat pumps if it's wired another way. but for regular gas heat, no.
    The heat exchanger are hotter with gas heat, and they need to get air moving over it so it don't over heat.

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