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Combi Boiler won't light

I have an NTI TI150. Recently, it has stopped lighting. The condition now is that I can see the burner glowing reddish/blue but the Fenwal or Sentry shut down the ignition moments later.
The gas/blower speed won't go above 80 (a number set n the Sentry 2100.
When it started not working, I was getting an ER6 lockout code with 3 flashes from the Fenwal. The cycle was turn on the boiler or "run" from the Sentry, the system would make a series of "clicks" as usual when starting. On about the third "click" the burner would shut off. This cycle repeats itself about 10 times before locking out with an ER6 code.
I've replaced the Fenwal, switched the Sentry2100 with an older unit I had on hand, swapped an older ignitor with the newer ignitor, opened up the combustion chamber and cleaned the condensed gas from the chamber, cleaned out the condensate drain (it was not clogged). Then I bypassed the flue, pressure, and temperature sensors on the red wire running between the Sentry and Fenwall and sensors. That's when I began getting the glow from the combustion chamber.
Any ideas are welcomed.
My next steps include getting a manometer to measure gas pressure, new ignitor, new flame sensor, new gaskets and maybe insulation, new air switch. Also will disconnect air intake to the boiler and blow out the intake line in case of a clog.
Help! Thanks.


  • Tom_133
    Tom_133 Member Posts: 891
    I use to keep the old igniter around as a spare because it worked when I pulled it out, but stopped after running into what you described and not thinking it was the igniter. It still may be your igniter. Also could be many other things. If I were you (if you are ok and comfortable doing this) I would open the heat exchanger and clean it real well, I would use white vinegar and a stiff bristled toilet brush, and an old credit card. Make sure to flush it after with clean water. When I put it back together i would clean the flame rod with a dollar bill real well, then I would clean the condensate trap and make sure it is clean and flowing.
    Montpelier Vt