Results 1 to 5 of 5

Thread: Humidity issues

Hybrid View

  1. #1
    Join Date
    Jul 2012
    Post Likes

    Hmm Humidity issues

    I have a customer that is having some humidity issues on the second floor of his home. He has a 2 ton heatpump and the square footage is around 1100 sq. ft. temp mantaines around the 72-74 degree range (100+ outside) with anywere from 11-13 degree delta tee but the humidity stays around the 60 percent range. If anybody can help it would be appreciated.

  2. #2
    Join Date
    Jun 2001
    Moore, Oklahoma, United States
    Post Likes
    I'd look at the blower speed, it might be set for 3 tons. High sensible capacity and low humidity removal would be the result. The 12 degree split also leads to this.

    Make sure the condenser isn't dirty, although this normally would result in the unit not cooling enough.

  3. #3
    Join Date
    Jul 2009
    Omaha, NE
    Post Likes
    What is your IWB? I am assuming it is somewhere in the middle 60's. What is the TESP? What is the fan speed set at? What is the SA and RA temps? Where is the SA duct work for second story located, inside or outisde the thermal boundary? Are there any RA grilles on the second story, if so, are they outside the thermal boundary? Where is the thermostat located? What is the R-value of the walls and attic? It does sound like there is too much airflow across the indoor coil, but I am curious to hear what some of the other operating conditions are.

  4. #4
    Join Date
    Jun 2007
    Greenwood Indiana (Indianapolis)
    Post Likes


    When there is too much air flow, the delta t is low. Also it makes the evaporator coil not as cold as it should be. Slowing the air flow to 350-400 cfm's per ton will help the unit dehumidify better. If this is 410a refrigerant, the ideal suction pressure is 120psi, which is about a 40 degree coil temperature.

    Post more information please.
    As iron sharpens iron so one man sharpens another Proverbs 27:17 NIV84

  5. #5
    Join Date
    Jun 2003
    Madison, WI/Cape Coral, FL
    Post Likes
    all good questions. A,C on/off cycle length in minimutes? Fan "on/off"? Temp outside?

    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

Related Forums

Plumbing Talks | Contractor MagazineThe place where Electrical professionals meet.
Comfortech 365