Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Trane ac air handler

Options
brion182
brion182 Member Posts: 3
in A-C, Heat Pumps & Refrigeration

I have a Trane air handler TWH039P 150C1 from ‘92 that just handles AC and the fan continuously runs but the compressor will cycle off. If I hit the relay I can get it to turn off so I think it’s just the relay and not the timer board. Problem is I can’t find this relay and would greatly appreciate some advice on what a replacement would be. I’ve attached photos of the original relay.
Thank you!

IMG_6143.jpeg
IMG_6127.jpeg
IMG_6126.jpeg

Comments

  • pecmsg
    pecmsg Member Posts: 6,314

    common Relay

    Supply House Dot Com

    mattmia2
  • 109A_5
    109A_5 Member Posts: 2,490

    Maybe (relay only)

    https://www.supplyhouse.com/Honeywell-R8222U1006-24-V-General-Purpose-Relay-with-DPST-N-O-switching

    image.png image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • JUGHNE
    JUGHNE Member Posts: 11,473

    The board may be for delay on break for the fan only. Runs the fan for a few minutes after shutdown of AC call from tstat.

    The board could be faulty to not shut the relay off or the relay contacts could be stuck in the on position.

    IIWM, I would just go for a standard relay with out the delay.

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 10,779

    That particular combination of PC Board and relay is an obsolete part that is no longer manufactured.  You can operate it without the PCB but there is a rewire that is needed to accomplish it.  Give me a minute to consult some old posts.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 10,779
    edited August 3

    This is the part number of the obsolete RLY02087 relay  It is a time delay PCB that connects to a R8222 general purpose relay used to delay the start of the fan for 30 seconds while the refrigerant (evap. coil) gets cold so less warm air goes through the ductwork on start up. Then there is a 60 second delay off at the end of the cycle so additional cooling energy can be recovered at the end of the call for cooling. It was an effort to hike up the SEER rating off a Trane condenser, or heat pump, that was matched to that particular air handler.  

    Since the system must be quite old and you are looking for the lowest cost repair, the overall SEER is less of a concern, so eliminating that PCB is no big deal.  The rewire is to remove the PCB completely from the R8222 general purpose relay, then remove the Red wire that powers the PCB on the one terminal of the relay coil.   If you only remove the PCB and leave the Red wire connected, the relay coil will always be powered, so the fan will run constantly.  

    Screenshot 2025-08-03 at 6.46.46 PM.png

    Typical Trane Air Handler Unit with obsolete relay wiring diagram with original on the left and the rewire on the right.

    Here is what it might look like on your air handler after you remove the PCB.

    Screenshot 2025-08-03 at 7.24.46 PM.png

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • HVACNUT
    HVACNUT Member Posts: 6,885

    If the TDR is ok, then a Honeywell R8222D1014 is most common.

  • brion182
    brion182 Member Posts: 3

    Thank you everyone! I will replace just the relay for now with the one that was suggested. If that doesn’t solve the issue and it’s the delay board I will re-wire using Edtheheaterman’s diagram.
    After tapping the relay last night it’s been working, we’ll see when I get home from work, either way I’m going to replace the relay.

    Thank you all very much!!

  • brion182
    brion182 Member Posts: 3

    Ed,

    I assume I can replace it then with the RLY02807? Looks like that has the time delay board built in. I think that is the way to go, looks like they’re under $100. I’ll just have to figure out the wiring.

  • mattmia2
    mattmia2 Member Posts: 13,602

    I think the time delay board just plugs on to a standard honeywell/residio relay.

Categories