Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Nti boiler no power all of a sudden

Hi two days ago I lost all power to my trinity nti T150 boiler , I checked the fuse it was good so I replaced the sentry 2100 controller and still nothing , any ideas??


  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    Call a professional? There is an NTI rep on this site, maybe he can get you in touch with the right person.

    There was an error rendering this rich post.

  • JakeCK
    JakeCK Member Posts: 1,401
    Don't fire the parts cannon right off the rip. That is a very expensive way to do diagnostics.
  • Jamie Hall
    Jamie Hall Member Posts: 23,536
    Time to find out how far you are getting power. It probably wasn't the controller... check your hot feed, check the neutral, and check the ground -- all the way from the fuse or breaker box to the boiler.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Tom_133
    Tom_133 Member Posts: 889
    Listen to Jamie, start from A and go through B,C,D... then to E. It sounds like this time you skipped a couple steps. That boiler has a few internal fuses, and if I remember correctly the sentry is powered by 24volt, so test transformer and safety loop. But it has been awhile.
    Montpelier Vt
  • Pacholopezr
    Pacholopezr Member Posts: 2
    Sorry for posting on top of an old topic. Something similar is happening to my NTI TI200 boiler. It powers off eventually. I have to cut the power for some minutes, sometimes as long as 10, then turn it on and the boiler goes back on. It is happening more and more often. Many parts have been replaced, including the Sentry 2100 panel. Reading through this post, it looks like going from A to E is the right thing to do. I am not a technician, but I am careful, respectful of electricity and gas, so I think I can use a voltmeter to test step by step. Is there any documentation about how to run this test ? Thanks a lot.
  • 109A_5
    109A_5 Member Posts: 1,388
    Hello @Pacholopezr,

    Probably a loose connection, when it heats up it fails. Check for loose connections at X4 with the 120 VAC power turned off. If your unit is intermittently going dead check the voltages at the same colored arrows 120 VAC and 24 VAC when the unit goes dead.

    The safest way is actually to use a clip lead to L2 and connected to one of the meter's test probes, test all the other places with the other probe in one hand, your other hand in your pocket and the rest of your body is not touching anything else, and insulated from a concrete floor. (NOT a probe in each hand) You can set up the meter and the clip lead ahead of time with the circuit breaker off.

    Also see 18.0 TROUBLESHOOTING in the manual.


    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • Pacholopezr
    Pacholopezr Member Posts: 2
    Thanks a lot @109A_5 sounds like a great suggestion. I will give it a try and let you know. Really appreciate it.