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  1. #1
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    Sep 2014
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    Confused New Trane install... ECM Questions

    Hello all!

    First post long time lurker. I tried to search for this but I couldn't find it.

    I had a new system installed this week after getting multiple quotes. I went with a Trane system.

    XT95 (100k BTU) paired with a XB16 (3.5 ton)

    This is roughly the same size of the old system that was replaced.

    House:
    Location: Kansas City
    2 story with 3/4 finished basement.
    2500 sq ft. 500 of that in the basement.
    house was built in 1996
    No external dehumidifier.

    The old system (installed when the house was built and it was builders grade) was able to keep me comfortable with a thermostat setting of 72 and the humidity in the house stayed between 40-45% in the summer.

    I find the new system feels comparable with the new thermo set at 68/69 but I am averaging around 47-54% humidity.

    Questions:
    1. the XT95 has an ECM motor but I don't hear a difference in the sound or pitch when the A/C is running. Does this mean it is running at a single speed the whole time? Shouldn't I be able to notice a difference in the 4 speeds the ECM has? When it receives the call/signal it just starts up to full speed it seems like and stays at that noise/speed until it quits.

    2. I am slightly concerned about the humidity increase. I have a feeling it might be related to the increased efficency and shorter run times with the new system. Shouldn't the XT95 with the ECM be able to run at a slower speed to help dehumidify?

    3. Could the board/ ECM wires be wired incorrectly thus preventing the ECM from running different speeds?

    So am I crazy or does it sound like it's working correctly?

  2. #2
    Join Date
    Jul 2001
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    Anderson,SC
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    Did the HVAC contractor install tonnage IAW Manual J and Manual D?
    Sounds like over sized and ecm/CFM setup wrong.

    Stud

  3. #3
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    Sep 2014
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    Thread Starter
    I doubt this will suprise you but.... I had 5 highly rated companies (many reviews on Angies List) give me quotes and not a single one did a calculation. Might just be my part of the country.

  4. #4
    Join Date
    Dec 2010
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    The Quad-Cities area (midwest).
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    Quote Originally Posted by jdwksu View Post
    I doubt this will suprise you but.... I had 5 highly rated companies (many reviews on Angies List) give me quotes and not a single one did a calculation. Might just be my part of the country.
    No, it almost is impossible to get a load calculation performed. That would require time and knowledge. You A/C is oversized. The new high efficiency systems do not dehumidify as well as your old 'builders model.'

    Because of that, proper sizing is more important than ever. You should get a thermostat that has a dehumidify feature. Then you should hear the fan (blower) slow down.

    What size is your filter?

  5. #5
    Join Date
    Jan 2014
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    New England
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    the XT95 series

    It includes a single-speed motor instead of a variable-speed motor. Most basic furnaces come with single-speed blower fan motors. It runs slightly less efficient and louder than a variable-speed motor.

    The unit also inlcludes a single-stage burner, instead of a 2-stage or modulating-stage gas burner. Operating in 1 heat-level, the burner does not maintain room temperature as well as units with more advanced

  6. #6
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    Sep 2014
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    Thread Starter
    Filter size is 5" 24x20 or something around that size.

    Do the thermostats with humidity function require hardwired power, my current thermo is battery.


    TUH1C100A9H41B Model # for the XT95 w/ Constant Torque ECM Blower Motor

    If I follow the manual it shows:

    FURNACE AIRFLOW (CFM) VS. STATIC PRESSURE (ins.w.g.)
    MODEL SPEED TAP 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
    TUH1C100A9H41B
    4 - HIGH - Black 1586 1552 1517 1477 1443 1410 1366 1331 1289
    3 - MED-HIGH - Blue** 1893 1858 1826 1793 1759 1724 1691 1646 1582
    2 - MED-LOW - Yellow 1364 1320 1282 1241 1205 1167 1120 1078 1045
    1 - LOW - Red 1107 1060 1003 959 919 863 825 782 730

  7. #7
    Join Date
    Dec 2010
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    Quote Originally Posted by jdwksu View Post
    Filter size is 5" 24x20 or something around that size.

    Do the thermostats with humidity function require hardwired power, my current thermo is battery.


    TUH1C100A9H41B Model # for the XT95 w/ Constant Torque ECM Blower Motor

    If I follow the manual it shows:

    FURNACE AIRFLOW (CFM) VS. STATIC PRESSURE (ins.w.g.)
    MODEL SPEED TAP 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
    TUH1C100A9H41B
    4 - HIGH - Black 1586 1552 1517 1477 1443 1410 1366 1331 1289
    3 - MED-HIGH - Blue** 1893 1858 1826 1793 1759 1724 1691 1646 1582
    2 - MED-LOW - Yellow 1364 1320 1282 1241 1205 1167 1120 1078 1045
    1 - LOW - Red 1107 1060 1003 959 919 863 825 782 730
    I'm sorry to tell you that your blower motor is not a variable-speed. It does not have dehumidification capabilities.

  8. #8
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
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    That's an x13 ecm motor which can be more efficient than a standard psc (depending on static pressure). A static pressure test would need to be performed to see if it should be on the med-high or med-low speed tap for cooling. My guess is med-low would give you more what you're looking for but static pressure will need to be measured to confirm.

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