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Transformer phasing

mtfallsmikey Member Posts: 765
I tried to explain this concept to my asst. chief engineer awhile back, after he blew out a control board on a Trane, it IS written!


  • Roland_4
    Roland_4 Member Posts: 84
    Transformer phasing

    Hi All,
    I remember this issue was addressed about a month ago but I can't seem to find it. There was a caution to make certain that all 24Volt transformers be properly phased when installing after-market boiler controls. I will be installing a Tekmar 256 and a seperate 24Volt transformer to power it. Does anyone know how to check the phase of the transformer? Thanks,Roland
  • Here it is

  • Roland_4
    Roland_4 Member Posts: 84

    Thanks Noel. What I was looking for. Roland.....
  • zeke
    zeke Member Posts: 223

    If you don't have electronics with their attendant noise problems, i.e. electromechanical only, then I personally DO NOT tie the grounds of the low and high voltage circuitry. I "float". 24 volts AC is hardly a shocking condition and if you inadvertently touch the hot ends you won't blow out the low level circuitry, as you would if you common grounded as suggested.
    I do not know if this is code, so you may have to check if you do it.
  • Dave Ackles
    Dave Ackles Member Posts: 1

    I am looking for the btu rating on this steel boiler mod. # CR76 REBCO most likely in the 1960s This boiler is not in the Byrley Book. Any help would be appreciated.
  • lee_7
    lee_7 Member Posts: 458

    satrt a new thread for your boiler questions, you will get better results.
  • Glenn Sossin_2
    Glenn Sossin_2 Member Posts: 592

    I think you got the name wrong - could it be Repco. The 76 probably represented the equivalent of the DOE rating or IBR rating. The time frame of the 60's sounds right. I wouldn't bother doing anything with a steel boiler that old other than replacing it. If thats what your doing, I would look at your actual radiation heat load, not the specs of that boiler.
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