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AO Smith Water Heater

Harvey Ramer
Harvey Ramer Member Posts: 2,239
Just this week I installed a new Cyclone MXI 199 water heater. I turned it on and it ran for 5 minutes and then shut down on an error and said the flame sensor was shorted out. I dickered with it for a little bit, then I pulled the flame sensor. It is a straight rod about 4" long. I noticed that the rod did not appear to be 100% aligned with the porcelain and the bracket. I laid it on a straight edge and straightened out the rod. It has run fine ever since.

Thoughts? Was it bent from the factory or did the rod warp from the heat? AO Smith says there are only 2 things that cause this error; water in the combustion chamber or cracked porcelain. Maybe we just found a third cause?


  • kcopp
    kcopp Member Posts: 4,443
    sounds like the sensor was bad from the manufacturer. Who ever put it into the water heater heat missed that it was bent....
    EBEBRATT-Ed Member Posts: 15,623
    @kcopp , or most likely didn't care.

    @Harvey Ramer

    Surprised they didn't tell you "we have never seen that problem before" or "all our equipment is factory tested" or "that just can't happen"
  • Rich_49
    Rich_49 Member Posts: 2,766
    Lest we forget JohnNY's disaster Cyclone from a couple years ago .
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
  • Steamhead
    Steamhead Member Posts: 16,899
    Rich said:

    Lest we forget JohnNY's disaster Cyclone from a couple years ago .

    That thread is here:


    It speaks for itself.

    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Harvey Ramer
    Harvey Ramer Member Posts: 2,239
    I well remember that thread. I looked at HTP but none of the Phoenix models met the demand. Most of them are capped at 160° degrees and the sanitizer model, which meets the required 180° temp, only has a 50 gallon tank. That's not enough to meet the requirement of 175 gallons of 180° water in the first 45 min.
    Ruud has a new Triton that may have the capacity. I haven't looked at them that much yet.