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Thread: Trane Rtha 255a

  1. #1
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    Trane Rtha 255a

    does anybody have a diagnostic troubleshooting repair manual for this chiller it has a classic black panel on it.The code it failed on was oil flow the tech said he bypassed it and then it came up saying transistion failure i beleive code was 8.My eagle software has expired so i cannot get the service manuals for this any help will be appreciated

  2. #2
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    bypassing the oil control wont work as it needs to see a change of state, In other words it has to see the safety open and then close before the chiller can run that is why you are seeing transition failure.

  3. #3
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    Thanks a lot what do you think could be my problem

  4. #4
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    thanks again mustardman I have my tech on the line now he clarified that the original failure was oil pressure switch closed he beleives D8, he says he pulled red wire off of switch to make it look like a open circuit he says he has 30 sec before oil flow switch has to close(seeing it seems to be stuck close). failure came up as transisistion failure without the unit ever even trying to start.What do you think.

  5. #5
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    heaviwall sorry it took so long to reply kids christmas concert. The way the manual and electrical reads is as follows. the oil flow switch needs to be open at start up and close within 30 seconds. or unit will shut down. If this switch is closed before start up you will get an oil failure or code e 8 as you have indicated. There was a service bulletin and I cant quite remember nor find it that was used to prevent these nuisance oil trips. You had to move the oil switch to be in series with the 2k2 contacts. These are the transition complete contacts. They are very small auxilliaries and fail often giving a bfo failure. check those first. If they are failed they need to be replaced with oem part as they are gold contacts. in the interim you can break the casing around the auxilliary and get at the contacts to clean them. In my experience if these two faults are happening it is usually those contacts.

    maybe you can get a copy of the service bulletin from Trane.

    Good luck

  6. #6
    Join Date
    Jul 2004
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    17

    Confused

    I do not understand ! The RTHA never had a clasic black panel. The CVHE made in the 80's did.

  7. #7
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    Not that it matters but do you have a flow switch or has it been converted to a pressure switch? E8 will occur if you go to 70 on the panel, it looks for an open oil flow switch then closes on start. I had one chatter the chilled water flow during startup which got the oil flow circuit out of sync and caused an E8 failure. Try RTHA - SB- 19
    "I'm from Texas, what country are you from?"

  8. #8
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    absctv you are correct the trane rtha never came with a classic black but what he means is it is a ucp1 panel which is also black in colour.

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