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Boiler power requirements....

Hello,

I have a Utica PEG187C steam boiler. All controls (LWCO etc.) are after the 24V transformer.
The transformer is a Honeywell AT150D.
The label says: "primary 120V 0.55A, secondary 24VAC, 50VA". So does this mean it only needs 120V x .55A = 66W to operate?
I called Utica and they said it needs 1.4A, which is (120V x 1.4A) = 168W....

Who is correct? I'm trying to find the correct size inverter/generator in case the power ever goes out during the winter.

I know that people say to measure the draw with a multi meter, but in theory can this transformer draw more power than what's stated on the label?

Thanks !

Comments

  • KC_Jones
    KC_Jones Member Posts: 5,692
    Are you sure they meant 1.4A @ 120V and not 1.4A@24V?
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • earhere
    earhere Member Posts: 7
    Thanks....yeah I was wondering that as well. They didn't clarify and I didn't ask as I'm fairly new to this and as of this morning didn't really know what a transformer does...

    But to your best knowledge can this transformer exceed .55A (@120V)? Would this be considered maximum draw or an average?
  • KC_Jones
    KC_Jones Member Posts: 5,692
    On transformers input basically equals output there are some minor losses heat inefficiency etc. If it is rated .55A then that's it, if you try and put more load on it than that you will most likely burn it up. The manufacturer puts those rating on for a reason.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • BobC
    BobC Member Posts: 5,471
    Transformers are inductive and the loads on that one are non linear. That means it can draw more current than you think, DO NOT DEPEND ON THE TRANSFORMER RATING TO CHOOSE THE INVERTER. The ad copy you see on inverters and generators is all too often little more than wishful thinking. If they don't mention power factor ratings all bets are off

    I would select an inverter that is rated at 2 or 3 times the rated load and make sure it's output is a sine wave. Make sure you can return it if it can't drive the load.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Mark N
    Mark N Member Posts: 1,115
    Does this boiler have electronic ignition, or a pilot? I remember after Hurricane Sandy there were issues with running boilers with electronic ignition off of generators or inverters. The spark module would not work.
  • earhere
    earhere Member Posts: 7
    Hi, it has a pilot. And yes i've heard issues like that too, when people are not using pure sine wave....these 24v controls seem to be very finicky with the AC quality.