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  1. #1
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    DEH3000R source of TEMP

    After weeks of trying to use a Nest 3 to control my new Ultra-Aire 120h the installer and I have given up and gone to a DEH3000R and it was easy to hook up and works great. I have one remaining question - despite reading and re-reading my DEH3000R Installer's & Owner's Manual I can't find the source for TEMP displayed on the control specified anywhere in the Manual. I assume it's the remote sensor as with RH as there are four wires. Am I right? Many thanks. John

  2. #2
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    I just looked back at the old manual I downloaded which combined the DEH3000 and DEH3000R and it answers the question saying "NOTE: If the DEH3000R is used, the external sensor must be connected in order to receive a signal for temperature and relative humidity." The new DEH3000R manual which came with the unit has no such statement.

    So question answered.

  3. #3
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    Jun 2003
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    The DEH3000R gets the temperature from the remote sensor.
    Thanks for the info on the lack of source of the temperature. A quick check would be to warm the remote or controller an watch the response on the display.
    Keep us posted on how your home response to the dehumidifier.
    Thanks for using our products.
    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"

  4. #4
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    Quote Originally Posted by teddy bear View Post
    The DEH3000R gets the temperature from the remote sensor.
    Thanks for the info on the lack of source of the temperature. A quick check would be to warm the remote or controller an watch the response on the display.
    Keep us posted on how your home response to the dehumidifier.
    Thanks for using our products.
    Regards Teddy Bear
    Teddy Bear, Thanks a million for getting back to me. You have been the source of most of what we have learned about dehumidifiers both through HVAC-Talk and your earlier blog postings which still have plenty of wisdom on the Ultra-Aire site.

    We've had our Ultra-Aire 120h installed for about a month and are slowly but steadily learning how to use it. We read up on dehumidifiers for about a year after moving to this 2600sq ft single family, single story home from a two story condo where we experienced black mold because of an oversized, short cycling AC unit. You may know that Austin from June to August can be pretty savage often with an August string of 100+ days and high overnight humidity. And we have two shoulder seasons that some feel are even worse. So perfect tests for a dehumidifier. We haven't had a chance yet to test our unit in the shoulder season but look forward to that. Our unit has the recommended dedicated return BUT, it now outputs to the return air plenum, because we were getting temperature spikes when the output was previously to the supply plenum.

    We have a few questions on which we'd value your opinion as making it all work seems to be part art as well as science.
    1. You noted the ASHRAE recommendation of 45% RH and 77° and we assume you still agree that's a reasonable set point.
    2. The DEH3000 has two "either/or" sets of hard wired alternatives, addressed as 2a and 2b below:
    2a. Energizing the AC central fan during dehumidifier operation seems helpful, because running the fan constantly just spreads humidity, and not running it with the dehumidifier restricts distribution of dehumidified air. Your thoughts?
    2b. Regarding activating or deactivating the dehumidifier when the AC runs - any hints you can provide would be helpful as we don't understand the pro's and con's.

    Many thanks for all your help to owners and contractors.

    AustinJohn

  5. #5
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    Quote Originally Posted by AustinJohn View Post
    Teddy Bear, Thanks a million for getting back to me. You have been the source of most of what we have learned about dehumidifiers both through HVAC-Talk and your earlier blog postings which still have plenty of wisdom on the Ultra-Aire site.

    We've had our Ultra-Aire 120h installed for about a month and are slowly but steadily learning how to use it. We read up on dehumidifiers for about a year after moving to this 2600sq ft single family, single story home from a two story condo where we experienced black mold because of an oversized, short cycling AC unit. You may know that Austin from June to August can be pretty savage often with an August string of 100+ days and high overnight humidity. And we have two shoulder seasons that some feel are even worse. So perfect tests for a dehumidifier. We haven't had a chance yet to test our unit in the shoulder season but look forward to that. Our unit has the recommended dedicated return BUT, it now outputs to the return air plenum, because we were getting temperature spikes when the output was previously to the supply plenum.

    Occasionally, the ideal dehu to a/c supply provides to much heat to a nearby sensitive space. Best to relocate on the supply side in a way to decrease the amount of warm air when the a/c is not operating. The negative part about connecting the dehu to the return duct is to avoid operating the dehu while the a/c is operating. Delivering dry air warm to the a/c return while cooling reduces the amount of moisture the a/c removes by an amount equal to the dehu's moisture removal. Using the DEH3000 control feature that interrupts the dehu operation during cooling. If you find a way to connect to the a/c supply instead of the return, no concern about dehu operation while cooling. If you a/c is setup ideally, the a/c should maintain <50%RH during significant cooling loads.

    We have a few questions on which we'd value your opinion as making it all work seems to be part art as well as science.
    1. You noted the ASHRAE recommendation of 45% RH and 77° and we assume you still agree that's a reasonable set point.

    ASHRAE suggest 40%-60% RH as a range of humidity. 77^F, 45%RH should be a good setting for many, especially with air movement from fans. When unoccupied, suggest a/c be higher or off. Humidity should not exceed 55%RH for long duration to avoid mold under carpets on concrete and dust mite control

    2. The DEH3000 has two "either/or" sets of hard wired alternatives, addressed as 2a and 2b below:
    2a. Energizing the AC central fan during dehumidifier operation seems helpful, because running the fan constantly just spreads humidity, and not running it with the dehumidifier restricts distribution of dehumidified air. Your thoughts?

    If you have a simple fan on your air handler, operating your a/c blower energy us is almost as much considerable, about 500 watts. With an separate return from the open space to the dehumidifier and the dehu supply to the a/c supply or return, a/c blower operating is not needed to cause circulation of the dry dehu throughout the home via supply/return ducts and back to the dehu return via the home. VS fans have advantage of very low re-circulation modes of <100 watts circulate about the same amount of air as the dehu, making it a smaller penalty to operate both. Homes with single speed air handlers would benefit by operating the dehumidifiers fan 24/7 for efficient air recirculation throught the home for 100-150 watts.

    2b. Regarding activating or deactivating the dehumidifier when the AC runs - any hints you can provide would be helpful as we don't understand the pro's and con's.

    This is covered above. On the supply side dehu connections, the negatives are what you experienced and the effect of high duct pressure if dehumidifying while cooling. This critical to dehus with very quiet fans, UA 98H/105H. Duct pressures of .6" WG wiil dramatically effect the capacity of most dehus.

    Many thanks for all your help to owners and contractors.

    AustinJohn
    Thanks again for your participation in this educational process (for all of us).
    Keep us posted as you go along. Are you adding fresh air to your home?
    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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    We can't begin to thank you enough for your prompt and helpful response. We also appreciate your commenting on the dehu output being changed from the AC supply plenum to the return plenum.

    We're not presently using the outdoor air feature because when we made our initial decisions we wondered how much benefit it could provide in the very hot temperatures we have for much of the year. Then later, as mentioned above, we were consumed with trying to use the Nest 3 the previous owner had installed to control the 120h until we painfully learned its shortcomings and switched to the DEH3000R. So thanks for the reminder on fresh air and having read your comments on adding fresh air, we're now inclined to do that once we get a few other projects lined out.

    And if you have a minute - we understand how a damper in the flex duct is important to prevent back draft when the dehumidified air outputs to the supply plenum. But where the dehu air outputs to the return plenum, is there some reason to have a damper (seems like it restricts air flow to the house).

    Thanks again. You are a gem.

  7. #7
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    Damper less critical when connected to the return.
    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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    Quote Originally Posted by teddy bear View Post
    Damper less critical when connected to the return.
    Regards Teddy Bear
    Many thanks, especially on Friday evening.

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