Question about temperature drop with Trane Comfort-R?
Results 1 to 4 of 4
  1. #1
    Join Date
    Jun 2002
    Posts
    460
    I have a Trane XV80 furnace and XL1200 (2.5 ton) air conditioner. The blower is set to 400 cfm/ton, but is also set to use the "Comfort-R" dehumidification feature, which I think (but am not sure) runs the blower at 80% of the set speed for 7 minutes or so.

    I checked the temperature of the air coming out of one of the registers today, and it was 48F! This was with the T-stat set at 72F and an outside temp of 74F. Based on the return and register locations, this is a drop of somewhere between 22 and 24 degrees, which seems like it's on the high side. Of course, all the ductwork and the inside unit are located in a very cool crawlspace, so maybe this is within normal limits.

    Should I have this checked or does this seem reasonable? The house is in the shade and with it having a crawlspace foundation, prone to being damp inside without A/C, so if this is OK I'd rather leave it this way and have the extra latent heat removal at the expense of some efficiency and/or sensible cooling.


  2. #2
    Join Date
    Jul 2004
    Posts
    322
    Not a pro, but if you are comfortable and your bills are okay, a 22-24 drop doesn't sound like a problem it it's only 74 outside, but others here are more knowledgeable.

  3. #3
    Join Date
    Jun 2002
    Posts
    460
    Originally posted by fat bob
    Not a pro, but if you are comfortable and your bills are okay, a 22-24 drop doesn't sound like a problem it it's only 74 outside, but others here are more knowledgeable.
    Hmmmm. Even with the temp in the low 80's this evening, I still measured 47.8F at one of the registers.

    Yes, the house is very comfortable. I just want to be sure I'm not about to have the coil freeze or have liquid get to the compressor.

  4. #4
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    After how much run time are you taking the temperature readings?

    If the system has been on for less than 8.5 minutes, 100% airflow has not been reached yet.

    If the humidity is very low, you will have a higher than "normal" temperature drop also.

    You could have low airflow.
    If the duct and/or filter system is very restrictive, it could overcome the ability of the varriable speed blower to maintain the correct airflow.
    If more government is the answer, then it's a really stupid question.

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