Page 1 of 4 1234 LastLast
Results 1 to 13 of 49

Thread: Need hvac help

  1. #1
    Join Date
    Sep 2014
    Posts
    18

    Need hvac help

    I hired a pro to install a new central air attic unit from scratch. I live in a 2 floor 2 family home in nyc I am trying to cool about 1400 sq ft. He installed it in May and has been in my home all summer long and can't get it right. It works well early in yen morning and late at night BUT in the day when the sun is out it don't reach temp I set it to 68 and it never goes below 72 they tryed adding additional return then they replaced the expantion valve then they moved both returns then they changes the thermostat, still not working it's is a 3 ton york unit. When it's cool outside the split temp is 19.2 then when the sun comes out it goes down to 14 f split. Now then are going to change the transition from the coil to the duck work. It's been 4 months can someone help me cause this guy just ain't doing it and I spent a lot of money

  2. #2
    Join Date
    Jun 2014
    Location
    Dover, DE
    Posts
    954
    Sounds like these guys are throwing parts at it and hoping it'll work.
    Get a second opinion.
    Why such the low set point?

  3. #3
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,477
    Probably duct leakage. Tell then you want a duct blaster test to confirm duct tightness.

  4. #4
    Join Date
    Sep 2014
    Posts
    18
    When set point is 70 on a hot day it still don't go below 71 or 72 I'm very unhappy at this point and now we won't be able to tell if they fix it cause there are no more hot days to test it out

  5. #5
    Join Date
    Sep 2014
    Posts
    18
    He checked all the duck work and re insulated it

  6. #6
    Join Date
    Sep 2014
    Posts
    18
    I keep telling him maybe I need a 4 ton unit but he says no

  7. #7
    Join Date
    Sep 2014
    Posts
    18
    Why would the temp split be 19 when it's cool out then drop to 14 when the sun comes out?

  8. #8
    Join Date
    Jun 2011
    Posts
    203
    Ask him to see the cooling load calculation, or have one done yourself. 3 ton for 1400 square feet could be light.

  9. #9
    Join Date
    Apr 2011
    Location
    SE Washington
    Posts
    554
    68 is really low for a residential system, check your local design temps, I bet it isnt at 68
    Total Energy Management, inc

  10. #10
    Join Date
    Sep 2014
    Posts
    18
    I asked him if he did a load calc he said that's just something that's done in school and that a 3 ton is more then enough. Can't keep fighting with this guy

  11. #11
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,477
    3 tons should be more than enough (oversized). You've got duct leakage and/or duct insulation problems. The tell tale sign is you have a 19* drop when the attic is cool and a 14* drop when the attic is hot. It could also be refrigerant charge related but more than likely its duct leakage. He's a hack if he thinks load calcs are only for the classroom and that probably means he doesn't think manual D (duct sizing) is needed either or manual S (equipment selection) or manual T (air registers/grilles). There's a science behind everything we do.

  12. #12
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,477
    Quote Originally Posted by isuredo View Post
    68 is really low for a residential system, check your local design temps, I bet it isnt at 68
    Design inside temp is whatever the customer wants, default is 75 but you can design to whatever indoor temp the customer wants, within reason, generally not lower than 68*. Lower than that begins refrigeration.

  13. #13
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,477
    Quote Originally Posted by Carbon View Post
    Ask him to see the cooling load calculation, or have one done yourself. 3 ton for 1400 square feet could be light.
    Where would 3 tons on 1400sqft be "light"? In Afghanistan or On the surface of the sun?

Page 1 of 4 1234 LastLast

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