Page 1 of 2 12 LastLast
Results 1 to 13 of 16
  1. #1

    Trouble with new evap coil

    I have installed a three and half ton condenser unit and a 4 ton evap coil in my modular home. I am having trouble with it wanting to freeze up. This is a Payne system, 13 SEER. It is a down flow system. The service tech from Carrier said that I wasn't getting enough air across the coil. So from his instructions I put a make shift sheet metal plemnom under neath it but still not sure that it's going to work (only 65 degrees today). I am thinking about going and getting a coil from a mobile home dealer and trying that. Any advise would be so helpful.
    Thanks,
    Virg

  2. #2
    Join Date
    Jul 2002
    Location
    Yuma, AZ
    Posts
    2,361

    Air carries the heat to the coil.

    The fan motor and blower that comes with the factory heater is not adequate for AC. Was it replaced? Another possibility is that the fan motor may not be running on high speed. The filter and coil must be clean also.

    Finally a system that is short of refrigerant, or not feeding the refrigerant properly, can make the coil freeze up. In this case, after defrosting, the coil is not full of evaporating refrigerant and only the top part would be cold and frosting. Eventually the frostline will move down as the frost blocks the airflow through the top part of the coil and finally will block the entire coil.

    Lynn
    "I have never let my schooling interfere with my education."
    Mark Twain
    More at: http://www.quotationspage.com/subjects/education/

  3. #3
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    Sounds like a DIY job gone bad.......


    either call the installing contractor or another company.
    If everything was always done "by the book"....the book would never change.

  4. #4

    Diy... Not

    I am a certified tech with 7 years experience. I have just ran into a problem that has not only me but a few others baffled. Help is what is needed not sarcasm. Thanks to Lynn for the help. Today it is 89* outside and the system has ran for about three hours now. It is cycling and yet it is starting to freeze a little on the evap coil. I have a 22 degree temp drop in the house. I have good air flow coming out each vent and yet still having this same problem. Payne equipment is good equipment made by Carrier, first time a problem with their stuff.

  5. #5
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    Quote Originally Posted by repvirg View Post
    I am a certified tech with 7 years experience. I have just ran into a problem that has not only me but a few others baffled. Help is what is needed not sarcasm. Thanks to Lynn for the help. Today it is 89* outside and the system has ran for about three hours now. It is cycling and yet it is starting to freeze a little on the evap coil. I have a 22 degree temp drop in the house. I have good air flow coming out each vent and yet still having this same problem. Payne equipment is good equipment made by Carrier, first time a problem with their stuff.

    Sarcastic? Not. If you're a certified tech, act as such , read the rules, apply for pro membership, and post in the tech section where you can get help. BTW, if this is "baffling" techs, have them apply also and read up.
    If everything was always done "by the book"....the book would never change.

  6. #6
    Join Date
    May 2006
    Posts
    122
    sounds like an airflow issue to me , is this a downflow gas furnace or down flow elec? is it possible you are bypassing air around the coil? They do make larger blower sections for these units. the blower should have a model number on it and the coleman/ intertherm dealer would be able to tell you if it can push enough air. After you get the air flow set up right, you should put a txv and a starter in the unit.

  7. #7
    Sounds like you should look in the installation book for a CFM chart for your particular furnace. If You have the proper 400 cfm per ton then, I would ask about restrictions in the TXV or TEV. Do a subcooling on your A/c. Also What type of duct work is in your modular home. Remember flex duct causes a 25% drop in airflow. Most 13 seer a/cs have a charging chart use that and get a chart for airflow in cooling over the evap, one a 75 degree day with average humidity (58-62 WB) you should be in the range of 50-55 degree air just outisde the coil.

  8. #8
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,963
    One of two things cause evap coil freeze ups; Low airflow or Low refrigerant charge conditions in the evap coil.

    If it absolutely is not airflow, then for whatever reason there is not enough refrigerant going into the evap coil.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


  9. #9
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Model numbers would help,for all equipment.

    Modulars are known to have undersized ducts ,at least here in the south with high cooling loads.

  10. #10
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,586
    Is this a new A/C install for this modular.

    Was it sized by the HUD sizing sticker.
    Or just by a guess.

    Judging the air flow by how hard its blowing out the registers doesn't tell you the volume.
    Contractor locator map

    How-to-apply-for-Professional

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

  11. #11
    Join Date
    Jul 2002
    Location
    Yuma, AZ
    Posts
    2,361
    Quote Originally Posted by repvirg View Post
    Today it is 89* outside and the system has ran for about three hours now. It is cycling and yet it is starting to freeze a little on the evap coil. I have a 22 degree temp drop in the house. I have good air flow coming out each vent and yet still having this same problem.
    1. Does the pattern of frosting when it is starting to frost cover the entire coil or only a portion of the coil? (To check it out, turn the fan off or block the airflow severly for a minute to see if the coil frosts uniformly and all over.)
    2. I presume that the SEER unit has a TXV metering device; can you confirm that? That is important information to have before we go further.
    3. Do you mean a 22 degree temperature difference (TD) between the return air temperature and the supply air temperature? Measure the Return air dry bulb temerature and the WET bulb temperature at the same time. (or get the local dewpoint temperature on the same day.) Withour knowing the airflow or the humidity load, the 22 degree temperature diference by itself does not provide enough information.

    RoBo Teq is absolutely correct, "One of two things cause evap coil freeze ups; Low airflow or Low refrigerant charge conditions in the evap coil.

    If it absolutely is not airflow, then for whatever reason there is not enough refrigerant going into the evap coil."

    Except there is a possibilty that you have BOTH problems and not just one.

    Lynn
    "I have never let my schooling interfere with my education."
    Mark Twain
    More at: http://www.quotationspage.com/subjects/education/

  12. #12
    Join Date
    Sep 2006
    Posts
    259
    wow, a certified tech with 7 years experience and he needed a carrier tech to give him instructions on how to buuild a "makeshift *plemnom*" lol.....sounds a little fishy to me

  13. #13
    Join Date
    Mar 2005
    Location
    Houston, Texas
    Posts
    11,874
    7 years =7 summers. Not really that much in the big picture.

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