2013



Results 1 to 9 of 9
  1. #1
    Join Date
    Apr 2006
    Location
    Florida, USA
    Posts
    3
    Rep Power
    0

    Trane HP Defrost Board Problem


    Amazing to have joined the board just in time to post the first question on the Heat Pump Forum.

    I have an 18 yr old Trane heat pump with a 21c140501 defrost control board. The outside fan will not run. Using multimeter I have determined that the NC relay on the DFC board is open. Haven't determined yet whether the relay is bad or something in the defrost control is calling for the fan to be stopped. The red led is flashing three quicks and a pause. On my other units the led gives a steady flash. I presume that is an error code.

    I jumpered the relay out of the fan circuit and the unit appears to be functioning normally. I will need to repair before heating season. An new OEM board is $360 so I really would like to know if I need it before shelling out the bucks. Any advice on troubleshooting would be appreciated.

    Regards, Ed



  2. #2
    Join Date
    Feb 2005
    Location
    Aberdeen
    Age
    38
    Posts
    168
    Rep Power
    10

    Re: Trane HP Defrost Board Problem

    Are there any temperature sensors within unit that may be holding off operation? If so, check them out, but on the other hand then you will have to fork out the dollars for new pcb.

    Jase

  3. #3
    Join Date
    May 2006
    Location
    Phoenix
    Posts
    2
    Rep Power
    0

    Re: Trane HP Defrost Board Problem

    Hey, Ed
    I'm working the same exact problem. I'm trying to cross the board to a replacement on the net. So, far I've found a board on a site. Do a search for a 21C140501G04, and you'll find what they recommend as a cross.

    Let me know if you find a cheaper control board.

  4. #4
    Join Date
    Apr 2006
    Location
    Florida, USA
    Posts
    3
    Rep Power
    0

    Re: Trane HP Defrost Board Problem

    Thanks for the replies. Phasegordon, I see the alternate pn. At least it's half the price. Thanks.

    I plan to pull all the inputs and power to the board and check to see whether the relay is still open. If it is I will replace just the relay. If not I will try to figure out how to troubleshoot the temp sensing circuits, I'd hate to replace the board and find out I still have the problem.

    Regards, Ed

  5. #5
    Join Date
    Jul 2006
    Location
    phoenix, az
    Age
    70
    Posts
    1
    Rep Power
    0

    Re: Trane HP Defrost Board Problem

    Ed,
    I am having the exact problem with Trane defrost controller board. I am wondering if your search for the replacement board was successful and if the replacement part has worked ? Thanks
    LaVar


    Quote Originally Posted by FastEd
    Amazing to have joined the board just in time to post the first question on the Heat Pump Forum.

    I have an 18 yr old Trane heat pump with a 21c140501 defrost control board. The outside fan will not run. Using multimeter I have determined that the NC relay on the DFC board is open. Haven't determined yet whether the relay is bad or something in the defrost control is calling for the fan to be stopped. The red led is flashing three quicks and a pause. On my other units the led gives a steady flash. I presume that is an error code.

    I jumpered the relay out of the fan circuit and the unit appears to be functioning normally. I will need to repair before heating season. An new OEM board is $360 so I really would like to know if I need it before shelling out the bucks. Any advice on troubleshooting would be appreciated.

    Regards, Ed

  6. #6
    Join Date
    May 2006
    Location
    Phoenix
    Posts
    2
    Rep Power
    0

    Re: Trane HP Defrost Board Problem

    I think you can fix these boards, by replacing the 2 onboard capacitors and the large power resistor. I fixed my board by doing this.
    The reason why, is that the electrolytic caps, age and wear out after many years at high temperature. The IC doesn't work so good without good filtered power. The IC controls the relay.

  7. #7
    Join Date
    Apr 2006
    Location
    Florida, USA
    Posts
    3
    Rep Power
    0

    Re: Trane HP Defrost Board Problem

    Phasegordon, do you have the specs handy for the caps and resistor? Is your repair still working?

    I have to do something soon it's getting cool in FL. With the relay jumpered I stay in AC mode.

    Regards, Ed

  8. #8
    Join Date
    Oct 2007
    Location
    Kitty Hawk, N.C.
    Age
    57
    Posts
    21
    Rep Power
    0

    Re: Trane HP Defrost Board Problem

    You should be able to find the board in question at a price below 360 bucks.
    If not, send me the model number of the H/P and I'll see if I can get you a board at a better price than that.
    Replace the board and avoid future problems with other resistors or components on the board in question.
    Once one portion of the board circuitry begins to fail, other problems with it are sure to follow.

  9. #9
    Join Date
    Sep 2008
    Location
    Fla
    Posts
    1
    Rep Power
    0

    Re: Trane HP Defrost Board Problem

    I'm having a problem with my heat pump that the local AC technician has diagnosed as a "bad control panel". The part is a 21c140501g04, same as discussed in this string. The panel is displaying three short flashes. What is happening inside the house is that the AC ceases to blow cold air when it gets really hot outside. Seems to work fine at night and in the morning, however.
    My question is if this is really what is wrong with this unit??? I ask because I have located a replacement board, but it's $187 plus $100 shipping, nonreturnable. I want to be sure before I spend that much money. Aqny help would be much appreciated; it's really hot here!

Similar Threads

  1. Defrost Problem
    By Mahmoud in forum Fundamentals
    Replies: 40
    Last Post: 19-10-2007, 10:15 PM
  2. Strange problem
    By Peter_1 in forum Electrical
    Replies: 9
    Last Post: 10-04-2007, 05:19 PM
  3. Circut on a main power split board ?
    By fridg in forum Electrical
    Replies: 13
    Last Post: 12-03-2006, 08:56 AM
  4. Hot Gas vs. Electric Defrost
    By herefishy in forum Technical Discussions
    Replies: 26
    Last Post: 08-03-2005, 08:50 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •