Results 1 to 5 of 5
  1. #1

    humidity proplems

    i've changed out an old r-22 AAF classroom unit with its 410a version and now having humidity problems , the units shutting off on temperature setpoint before it takes care of the humidity in the classroom . i read through the manual and theirs nothing in it to program to help.

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,599
    Moved to AOP Commercial.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  3. #3
    Join Date
    Jun 2006
    Location
    New Jersey
    Posts
    4,340
    Quote Originally Posted by lp14255 View Post
    i've changed out an old r-22 AAF classroom unit with its 410a version and now having humidity problems , the units shutting off on temperature setpoint before it takes care of the humidity in the classroom . i read through the manual and theirs nothing in it to program to help.
    You got a model number off it?

    Normally those units don't have any sort of humidity control. So I would look at infiltration. What's the OA damper doing?

  4. #4
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,841
    Is this the same size in Btus'? Perhaps there's an ill fitting sleeve and air infiltration?

  5. #5
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,597
    Anything that results in a cooling coil that is not cold enough to remove the moisture from the air will raise the indoor %RH. A properly charged system with the right amount of air flow over the coil will remove moisture. Excess fresh air infiltration will also raise the indoor %RH. A 45^F coil temp is minimum to get to a 75^F, 50%RH, 55^F dew point. Classrooms with 30 occupants and 400 cfm of fresh air are difficult to maintain <50%RH. This could be 20 lbs. of moisture per hour.
    If these spaces are wet for extended many days, expect mold to grow. We have several schools that do the best they can when occupied. They operate dehumidifiers when unoccupied to maintain <50% RH. The make-up air is off and the a/c is off when unoccupied.
    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"

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event