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  1. #1
    Join Date
    Jul 2012
    Location
    South Florida
    Posts
    9

    New XL20i owner, have concerns

    New member here, looking for some advice... Thanks in advance to all who participate in this forum, making your knowledge available to the masses... its very much appreciated!

    I had an XL20i professionally installed by a large and reputable installer in the SoFla area. My problems are as follows.

    #1 The slab is always wet, not just a little... its a permanent puddle (now full of mold as well). I have had the installer out numerous times and now they are saying "this is normal". My neighbor has the exact same unit, installed by the same company... and hers is totally dry. Is this in fact normal?

    #2 The humidity inside the house is low... in the mid 30%. I'm waking up everyday with a scratchy throat since this unit was installed. The house is 1750sq/ft and this is a 3T unit. It runs on low speed pretty much non-stop 24x7, I assume this why the humidity is so low. I have asked the installer about this as well, he said "low humidity is a good thing"... and I agree as long as its comfortable, which its not. Can this be adjusted?

    Thanks again for any advice, Mark

  2. #2
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,060
    Quote Originally Posted by TheMark View Post
    New member here, looking for some advice... Thanks in advance to all who participate in this forum, making your knowledge available to the masses... its very much appreciated!

    I had an XL20i professionally installed by a large and reputable installer in the SoFla area. My problems are as follows.

    #1 The slab is always wet, not just a little... its a permanent puddle (now full of mold as well). I have had the installer out numerous times and now they are saying "this is normal". My neighbor has the exact same unit, installed by the same company... and hers is totally dry. Is this in fact normal?

    #2 The humidity inside the house is low... in the mid 30%. I'm waking up everyday with a scratchy throat since this unit was installed. The house is 1750sq/ft and this is a 3T unit. It runs on low speed pretty much non-stop 24x7, I assume this why the humidity is so low. I have asked the installer about this as well, he said "low humidity is a good thing"... and I agree as long as its comfortable, which its not. Can this be adjusted?

    Thanks again for any advice, Mark
    Have them determine what the airflow is. not just what the dip switches are set at. Low cfm equals low superheat equals sweating compressor and could lead to compressor failure if flooding is involved.

  3. #3
    Join Date
    Aug 2011
    Location
    Eastern Shore, MD
    Posts
    798
    #1: could be normal. sounds like yours is either sweating too much OR hers is not sweating enough. that could be a charge issue, air flow issue, or even a sizing issue

    #2 it can be adjusted... have them adjust the humidity setting or even lock out low stage

  4. #4
    Join Date
    Jul 2012
    Location
    South Florida
    Posts
    9
    Quote Originally Posted by second opinion View Post
    Have them determine what the airflow is.
    Just so I fully understand what to expect from this request, how is the airflow determined?

    Where are these dip switches located? so I can look at them... would it help if I posted a pic here of them?

    Thanks again.

  5. #5
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,366
    Quote Originally Posted by TheMark View Post
    New member here, looking for some advice... Thanks in advance to
    #1 The slab is always wet, not just a little... its a permanent puddle (now full of mold as well). I have had the installer out numerous times and now they are saying "this is normal". My neighbor has the exact same unit, installed by the same company... and hers is totally dry. Is this in fact normal?

    #2 The humidity inside the house is low... in the mid 30%. I'm waking up everyday with a scratchy throat since this unit was installed. The house is 1750sq/ft and this is a 3T unit. It runs on low speed pretty much non-stop 24x7, I assume this why the humidity is so low. I have asked the installer about this as well, he said "low humidity is a good thing"... and I agree as long as its comfortable, which its not. Can this be adjusted?

    Thanks again for any advice, Mark
    45%RH-50%RH should be the ideal humidity for comfort and health. What is the indoor temperature setting? At 75^F, 50%RH, which is 55^F dew point, you need a 45-50^F cooling coil temperature.
    Colder cooling coils cause lower %RH and excess sweating of the ducts, condensing units on slabs. Increase the air flow of indoor air handler until you reach 45-55%RH. Many FL homes have restricted air ducts. Open all indoor supply vents and have clean air filters. Air handlers can be adjusted to provide more air flow. Your tech will do this.
    During cool wet weather, your %RH will be much higher. Some techs over dry the air to help with this problem. It is not a good solution. For <50%RH during no cooling loads, a whole house dehumidifier is best solution.
    Keep us posted.
    Regards TB
    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
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Quote Originally Posted by Gross View Post
    #1
    #2 it can be adjusted... have them adjust the humidity setting or even lock out low stage
    kinda defests the point of having 2 compressors doesn't it? Besides, if hte fan is set to auto, and hte unit is sized correctly, it might not make as much difference as you think. Latent capacity is sometimes higher in 2nd stage depending on the airflow settings.

    The maximum airflows should be adjustable for each stage with the communicating controller. The humidity adjustment sholdn't make a difference, unless it's set to 35%RH. I think carrier Infinity doesn't even go that low.

    How cold are you keeping the home? You might want to try keeping a few degrees warmer and see if comfort is the same. Not only will you save energy, but the unit will run less and shouldn't drop the humidity as low.


    I suspect hte airlfow setting for low stage is a little low and is set there because normally these systems are oversized. But in your case, you probably have a fair amount of solar gain and the system is able to really drive the moisture out.


    Personally, my system downstairs holds humidity in the mid 30's and it's very comfortable, but we also keep it 76-77F.

  7. #7
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Quote Originally Posted by teddy bear View Post
    45%RH-50%RH should be the ideal humidity for comfort and health. What is the indoor temperature setting? At 75^F, 50%RH, which is 55^F dew point, you need a 45-50^F cooling coil temperature.
    Colder cooling coils cause lower %RH and excess sweating of the ducts, condensing units on slabs. Increase the air flow of indoor air handler until you reach 45-55%RH. Many FL homes have restricted air ducts. Open all indoor supply vents and have clean air filters. Air handlers can be adjusted to provide more air flow. Your tech will do this.
    During cool wet weather, your %RH will be much higher. Some techs over dry the air to help with this problem. It is not a good solution. For <50%RH during no cooling loads, a whole house dehumidifier is best solution.
    Keep us posted.
    Regards TB
    It's a VS air handler so it's probably not short on airflow in low stage. It's probably been set-up this way. But I agree, the airflow needs to be increased. You are correct, it's possible that the ductwork is undersaied and the installer set up the system with low airflows to keep it from being noisy. If this unit is in 1st stage all the time, then it could be oversized. But in that climate with 1750sqft, unless it a very tight well insulated home, it's probably about right.

  8. #8
    Join Date
    Jul 2012
    Location
    South Florida
    Posts
    9
    Quote Originally Posted by teddy bear View Post
    45%RH-50%RH should be the ideal humidity for comfort and health. What is the indoor temperature setting? At 75^F, 50%RH, which is 55^F dew point, you need a 45-50^F cooling coil temperature.
    Colder cooling coils cause lower %RH and excess sweating of the ducts, condensing units on slabs. Increase the air flow of indoor air handler until you reach 45-55%RH. Many FL homes have restricted air ducts. Open all indoor supply vents and have clean air filters. Air handlers can be adjusted to provide more air flow. Your tech will do this.
    During cool wet weather, your %RH will be much higher. Some techs over dry the air to help with this problem. It is not a good solution. For <50%RH during no cooling loads, a whole house dehumidifier is best solution.
    Keep us posted.
    Regards TB
    Thanks for this, I currently set the temp at 75 and have the humidity at 60%. The fan nearly never spools up... it just runs on low all the time, your explanation makes perfect sense. I will try to get them to increase the airflow. All the vents are wide open and ductwork was "cleaned" when they installed the unit. I replace the filter every 30 days as well.

    I'm going to try moving the temp up to 76 now and check in a few hours if the humidity goes up.

  9. #9
    Join Date
    Jul 2012
    Location
    South Florida
    Posts
    9
    Quote Originally Posted by motoguy128 View Post
    It's a VS air handler so it's probably not short on airflow in low stage. It's probably been set-up this way. But I agree, the airflow needs to be increased. You are correct, it's possible that the ductwork is undersaied and the installer set up the system with low airflows to keep it from being noisy. If this unit is in 1st stage all the time, then it could be oversized. But in that climate with 1750sqft, unless it a very tight well insulated home, it's probably about right.
    The unit they replaced was a 4T, this new one is a "strong 3T" as they put it. The house is not very tight... as all the hurricanes a few years back blew all the windows loose. Plus my kids are always going in and out the doors...

  10. #10
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    4,627
    Turn uP the humidity level at the stat. Also the suction line is below dew point sothere will be condensation on the slab

  11. #11
    Join Date
    Jul 2012
    Location
    South Florida
    Posts
    9
    Quote Originally Posted by catmanacman View Post
    Turn uP the humidity level at the stat. Also the suction line is below dew point sothere will be condensation on the slab
    Turn it up higher than 60%? Will that matter if it never even approaches the 60% its currently set at?

    Thanks

  12. #12
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,060
    Quote Originally Posted by TheMark View Post
    Just so I fully understand what to expect from this request, how is the airflow determined?

    Where are these dip switches located? so I can look at them... would it help if I posted a pic here of them?

    Thanks again.
    The dip switches are located on the control board.

    The dip switches are set to what you want the unit to provide and then it should be varified that it is providing it at the correct static pressure.

    Posting pics of the dip switches and wiring always helps.

  13. #13
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Quote Originally Posted by TheMark View Post
    The unit they replaced was a 4T, this new one is a "strong 3T" as they put it. The house is not very tight... as all the hurricanes a few years back blew all the windows loose. Plus my kids are always going in and out the doors...

    It must be the airflow setting then. Could be just a simple dipswitch change.

    Changing the humidity setting above 45% won't make any difference. Your system is likely not in "dehumidifying" mode. What temerpature do you have it set at?

    35%RH at 72F is a lot different than 35%RH at 76F.

    You may have a lot of heat gain form windows and maybe minimal shade and/or attic insulation. The more heat gain you have in hte same size house, the lower your indoor humidity will be. Get pictures if you can of the dis switch settings on the control board in the air handler. The control board is inside the cover on hte air handler. IT should have some little knobs you turn to open it. It may shut off the power when it opens it. That's normal.



    Hey pro's, when is the last time we had a "my home is too dry" in a hot humid climate???

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