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Thread: Ultra Aire 155 dehumidifier perhaps dying (again)

  1. #1
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    Ultra Aire 155 dehumidifier perhaps dying (again)

    Hi,

    I hate to have to post this... but once a year my Thermastor Ultra Aire 155xt dies and needs to be replaced. I am on my 3rd unit in as many years and I am concerned this one is starting to fail.

    All summer it has been operating very consistently with output temps around 90 and dew points about 5 degrees lower than the intake air.

    Today it started operating inconsistently with very high output temps being recorded (as high as 111 degrees F). Please see recent temperature / dew point charts attached. The input air has been slightly drier in the past but basically fairly consistent.

    I have turned the unit off for now but would like some idea from anyone what might be going on. I have attached 2 images/charts... one for the last 24 hours and another for the last 7 days.

    Any help is appreciated.

    Thanks... George
    Attached Images Attached Images   

  2. #2
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    We expect a 10^F drop in dew point as the air passes through the dehumidifier with a 75^F, 50%RH, a 55^F dew point. Supply temps like 90-95^F, <20%RH, 46^F dew oint.

    4lbs. of dehumidificqtion with low of moisture level.

    Any decrease in air flow will raise the temperature and decrease moisture removed. You are operating above normal temperatures and below normal dew points. This will raise the output temperatures. The unit is rated at 80^F, 60%RH at 155 lbs. per day or about 6 lbs. of dehumidification per hour.

    Try operating at the rated conditions and measure the moisture output. Also the air flow is open on return and supply. Increasing the duct pressure decreases the dehumidification rate and increases the supply temperature. Also measuring extreme high or low %RH accurately is difficult. Raise the %RH setting to 50%RH setting if possible. Lower settings extend run time and decrease capacity. You may even have coil freezing at the extreme low settings.

    If you get the unit to Madison, our service dept. will check it out.

    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"

  3. #3
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    HI TB,

    I have a temp/hum device on the input side and on the output side and I am only seeing a 3-4 degree drop in DP with 73 degrees / 54% humidity in the input side.

    The wild fluctuations that I measured yesterday have gone away but the unit is not working the way it should. I have checked the air flow and there are no issues there.

    I am working (again) with Justin at Thermastor.... but while the replacement warranty has been honored the uninstall/installation of each unit has been a problem for me.

    This is the 3rd unit in as many years to fail and this is more than very concerning to me.

    Thanks,

    George

  4. #4
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    Thread Starter
    Quote Originally Posted by teddy bear View Post
    We expect a 10^F drop in dew point as the air passes through the dehumidifier with a 75^F, 50%RH, a 55^F dew point. Supply temps like 90-95^F, <20%RH, 46^F dew oint.

    4lbs. of dehumidificqtion with low of moisture level.

    Any decrease in air flow will raise the temperature and decrease moisture removed. You are operating above normal temperatures and below normal dew points. This will raise the output temperatures. The unit is rated at 80^F, 60%RH at 155 lbs. per day or about 6 lbs. of dehumidification per hour.

    Try operating at the rated conditions and measure the moisture output. Also the air flow is open on return and supply. Increasing the duct pressure decreases the dehumidification rate and increases the supply temperature. Also measuring extreme high or low %RH accurately is difficult. Raise the %RH setting to 50%RH setting if possible. Lower settings extend run time and decrease capacity. You may even have coil freezing at the extreme low settings.

    If you get the unit to Madison, our service dept. will check it out.

    Keep us posted.

    Regards Teddy Bear
    Just an update.... this morning the unit is not dehumidifying at all. The local tech here in Atlanta believes that these units have a refrigerant leak problem with the higher running pressures using the 440a. Since this is the 3rd unit to fail for me in 3 years I am wondering if there is not a design flaw with these units.

    Anyhow... I will get back to Justin and see what our next steps are to fix this problem for me.

    George

  5. #5
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    Any of the coil leaks have involved coil corrosion not pressure failure. The UL codes have high safety pressure factors.
    Chemicals in the air are one of the causes.
    Is there fresh air provided as part of the installation? Suggest if no fresh air, add fresh air to the space to purge the chemicals that might be involved. A 6"fresh air duct connected to the return side of the dehumidifier will provide 60-80 cfm of fresh air when operating.

    Sorry about the problem. May be site specific soil gas or a pollutant in the space.

    Ask Justin to check the coil if it is replaced. If changing the unit out is difficult, what about replacing the coil on site.

    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"

  6. #6
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    Quote Originally Posted by teddy bear View Post
    Any of the coil leaks have involved coil corrosion not pressure failure. The UL codes have high safety pressure factors.
    Chemicals in the air are one of the causes.
    Is there fresh air provided as part of the installation? Suggest if no fresh air, add fresh air to the space to purge the chemicals that might be involved. A 6"fresh air duct connected to the return side of the dehumidifier will provide 60-80 cfm of fresh air when operating.

    Sorry about the problem. May be site specific soil gas or a pollutant in the space.

    Ask Justin to check the coil if it is replaced. If changing the unit out is difficult, what about replacing the coil on site.

    Keep us posted.
    Regards Teddy Bear
    HI.. thanks for the reply.

    I have tried running this unit with fresh air and without fresh air... same results of unit lasting only one year. Our house was built in the early 70s so we get enough air infiltration due to natural "leaks" in older homes.

    I just don't think we have chemical issues. Our crawl space has been professionally sealed (on all sides) and in addition we have very HQ air filtration in the house using several EnviroKlenz units (https://enviroklenz.com/product/envi...obile-uv-model) along with AC HEPA filtration and VOC removal. We also use a product called purple air which measures the air quality indoors and outdoors. Our AQI is typically less than 5 indoors. See https://www.purpleair.com/ for more information if you like.

    Our first whole house dehumidifier was installed around the year 2000 which lasted for 15 years with no issues. It was a DVA 400 and I believe it was manufactured locally down here near Marietta or Kennesaw, Georgia. It was rated around 150 pints/day. This is why I find it so disappointing that the Thermastor Ultra Aire is failing once a year. Makes no sense to me.

    Anyhow I am working with Justin and am confident he will take care of my situation.

    Thanks.... George

  7. #7
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    A comment on "enough air leakage". During windy weather and some stack effect, you get enough fresh air. During calm, mild weather, even leaky homes may only get a fresh air change in 12 hours verses a fresh air change in 4 hours during average winter conditions. All of this may not be critical to your situation. Just talking about the problem in general.

    Keep us posted. I would like to see the coil that comes out of your unit if is replaced. Mention this to Justin.

    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"

  8. #8
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    Thread Starter
    OK... will do.

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