Page 1 of 2 12 LastLast
Results 1 to 13 of 15
  1. #1
    Join Date
    Nov 2012
    Location
    Richmond Va
    Posts
    4

    New heat pump installed.

    Last month I had a complete new system installed with all new duct work. The new system was working awesome (even temp throught home) untill about 3 to 4 days ago. The issue is half the house can be 71 and the other is 69. The installer added a small return for the side that now is 1 to 2 dregrees colder. So I did some looking and what I found was that the new return is almost closed shut. Looks like flex duct was use at the return.
    I know a quite a bit about airflow! I had a few hotrods. I know for a fact that to get air to make a 90 degree turn you have to have a gradual bend.
    What should the total air flow for a 3 ton system be? Is there a min/max system pressure that can be messured?
    Suggestions to what to ask the installer to check??

  2. #2
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    33,396
    To me, a 2° difference is great. You'll have different loads at times such as afternoon sun or lights and people. He can play around forever trying to balance airflow but since this load varies, it will never be perfect.

  3. #3
    Join Date
    Jun 2006
    Location
    Richmond, VA
    Posts
    2,693
    It's hard to say without seeing the duct and what you have for balance problems. Adding a return helps the available supply static pressure and therefore affects flow into the room.....but it does it for the whole supply duct system so the hot side will get more air too. 2 degrees isn't that much due to the fact 1 thermostat centrally located with duct going to a bunch of rooms with different heating and cooling loads.....

    If the duct is sealed well, and depending on the equipment, fan on low for recirculation MIGHT get you perfect.
    It's not the Brand with the fewest repairs-It's all in the install!!! Attention to detail and using the best materials!

  4. #4
    Join Date
    Sep 2002
    Location
    Northeast Ohio
    Posts
    4,802
    I agree that 2 degrees is minimal considering variable heat gain/losses that are prevalent in most structures. It may be possible for the contactor to balance the system using dampers keeping in mind that the conditions will change heating to cooling season. I might possibly try running the system blower in a continuous low speed circulation mode to see if that helps balance out the temperature.
    A good HVAC tech knows how, an educated HVAC tech knows why!

    DEM


  5. #5
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    3,948
    +4, 2 degrees is great

  6. #6
    Join Date
    Nov 2006
    Location
    Athens, Ohio
    Posts
    1,383
    for 2 degrees. Same for running the fan. I will guess that the weather has changed recently and you now have more heat gain (or loss) in certain areas of the house at different times of the day.

  7. #7
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,852
    Quote Originally Posted by JJoe View Post
    What should the total air flow for a 3 ton system be? Is there a min/max system pressure that can be messured?
    Suggestions to what to ask the installer to check??
    Nominal amount of air for a 3 ton system should be 1,200 CFM.

    The shorter the distance where the conditioned air must travel to "return" to the system, the less temperature difference there will be. Flex ducting must be as straight and pulled as taut as is reasonable to be most effective.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


  8. #8
    Join Date
    Nov 2012
    Location
    Richmond Va
    Posts
    4
    Guy's thanks for your insight! Since I have a Perstige IAQ 2.0 thermostat I have already thought about and ordered a remote Stat as the main one is not located in a central location. That should resolve my little issue! Its hard not to worry when you spend $$$$$. Again I thank you for your time. Have a wonderful day.

  9. #9
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,786
    Set the fan to circ, and see if that doesn't help.
    Contractor locator map

    How-to-apply-for-Professional

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

  10. #10
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,852
    Quote Originally Posted by beenthere View Post
    Set the fan to circ, and see if that doesn't help.
    Good idea, especially if your system has an ECM blower that runs at 50% volume in fan mode when no heat or cooling is being called for.

    Also, shut off the supply regester closest to the thermostat.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


  11. #11
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,632
    ...and maybe bump the setting a degree or two.
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

  12. #12
    Join Date
    Nov 2012
    Location
    Richmond Va
    Posts
    4
    Name:  DSC02237.JPG
Views: 135
Size:  144.7 KB It just looks like to me that it can't flow much if any air. It's no more than 1 inch from the top of the sheet metal.

  13. #13
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    3,948
    Looks like the straight piece of sheet metal should have been a "hard 90". Hard to say for sure w/o seeing the job.

Page 1 of 2 12 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