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  1. #1
    Join Date
    Mar 2020
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    1
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    New Trane XR15 doesn't dehumidify as well as old Intertherm

    My first post. I'm here to learn. Be gentle.

    I had a new Trane XR15 (manufactured 9/2019) installed in November 2019. It works fine, but doesn't dehumidify as well as my old Intertherm system. This is a split system with outside compressor and inside air handler. When I ran the A/C with my old unit the humidity never got about about 45%. It felt cold inside when it was set to 75 deg because the air was dry.

    With the XR15, inside humidity stays around 52-53%. I have to keep it as a lower temp to get the same comfort level I had with the old unit at 75 deg.

    I recognize these are totally different units. Should the XR15 be lowering the humidity to 40-45%? Is there anything I can do to increase the amount of dehumidification?

    I had a technician here yesterday from the company to check the refrigerant level. It is fine.

    A new Honeywell VisionPRO 8000 thermostat was installed with the XR15.

  2. #2
    Join Date
    Jan 2014
    Location
    New England
    Posts
    6,710
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    How did he check the refrigerant level, by pressure only? Or by subcooling, superheat, a combination, did he follow the manufacturers guide to check and adjust charge? What did the invoice say?

    Same size or smaller tonnage as your old unit? Different CFM movement?

    Did you register your system to get the 10/10 compressor and parts warranty.

  3. #3
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
    27,144
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    Super Heat
    Sub Cooling
    CFM's
    TSEP

    All have to be checked

    Fine is not a level!

    How did they check in November, was it hot out?

    Tell them you want a FULL Start up and Commissioning Report. Takes about 1/2 a day if everything's right.

  4. #4
    Join Date
    May 2014
    Location
    Bay Area California
    Posts
    26,506
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    If you put in a system of greater capacity than your old system, that's your problem. Not running long enough to get the same de-humidification.
    I do a triple evac with nitro to remove non condensables.

  5. #5
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    9,763
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    Quote Originally Posted by Bazooka Joey View Post
    How did he check the refrigerant level, by pressure only? Or by subcooling, superheat, a combination, did he follow the manufacturers guide to check and adjust charge? What did the invoice say?

    Same size or smaller tonnage as your old unit? Different CFM movement?

    Did you register your system to get the 10/10 compressor and parts warranty.

    A lot of good comments. It is a combination all of the above. The final adjustment is the air flow. This determines the amount of moisture removal verses the sensible cooling rate. Less air flow produces colder air with a lower dew point, and higher %RH condition air.

    Too cold and the coil may freeze and the supply ducts sweat. A/c not running, no moisture is removed.
    evenings, days with +mediun outdoor dew points, and rainy days make the home damp.
    Occupants with health and comfort issues will do much better if the indoor %RH is <50%RH.
    Adding a small whole house dehumidifier will keep homes <50%RH during most green grass climate conditions.
    Keep us posted.
    Regards Teddy Bear
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

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  7. #6
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    40,746
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    Model # of air handler? Model # of thermostat? Do you run the fan on auto? Same size as oldie? New A/Cs often don't dehumidify as well as oldies so a dealer just going with same size, which was likely oversized, can cause you trouble.

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  9. #7
    Join Date
    May 2014
    Location
    Bay Area California
    Posts
    26,506
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    Call a tech and have him/her put the blower on low speed for cooling, and high speed for heating. That's what I did, except I'm the tech, LOL. Been like that for over 20 years now, love it.
    I do a triple evac with nitro to remove non condensables.

  10. Likes ksefan liked this post.

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