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HTP Fire Tube Boiler overheating

RedicliffRedicliff Member Posts: 1
We have an HTP flash heater MC-100 that is overheating.
I've posted a 1.5 min video of the control panel as the unit cycles. Boiler

Not finding corresponding troubleshooting recommendations in the manual. Of course, if it's there, it probably reads "call a certified tech". But, we're sheltered in place a long ways from a tech.

Comments and recommendations appreciated


  • kcoppkcopp Member Posts: 3,514
    From the description you are not getting flow. Is something shut off, circulator broken or debris plugging the piping?
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 7,094
    Or no or low water pressure in the system.
  • fenkelfenkel Member Posts: 81
    Check your pumps..water isnot moving thru HX..
  • GroundUpGroundUp Member Posts: 991
    Not enough flow, can hear it boiling in the HX. How's it piped?
  • hot_rodhot_rod Member Posts: 13,509
    they can be tricky to purge the boiler on fire tube design. i have had to hold the relief valve open if you do not have enough purge flow or pressure.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • fenkelfenkel Member Posts: 81
    Whats the boiler pressure? Should be a guage under the boiler?
    Upload more pictures, sometimes we can see issues..
  • Rich_49Rich_49 Member Posts: 2,540
    If this in fact an MC series boiler , it is not a firetube . MC Series was a water tube boiler
    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
  • fenkelfenkel Member Posts: 81
    How old is boiler?
    Could HX be plugged?
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