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NTI TRX (Water-Tube) vs FTVN (Flame-Tube) Boiler, when it comes to maintenance

C_Herzog Member Posts: 1
So, I need to replace my 20 YO NTI T150 that gave out on me last season with a new boiler, and I believe I've narrowed it down between the TRX or the FTVN.

The conventional wisdom is that the vertical flame-tube combustion chamber on the FTVN will require less frequent cleaning and be just as easy to perform, but is that the case? I'm looking at the two installation manuals now, but would appreciate some feedback from anyone who has cleaned both of them.

Thanks in advance.


  • Tom_133
    Tom_133 Member Posts: 888
    I have a FTVN and it's been great. The heat exchanger is very easy to clean. I have installed somewhere around 25 of them and they are pretty good. They are not as good as that T150 you had. In order to get that quality you need to step up to the TFT series. You will probably want to get a supply/return sensor to keep on hand, for some reason they are the fail point on a FTVN. The TRX is the Giananni HX and when it comes to LP it's a less forgiving on the cleaning side. Still works ok.
    Montpelier Vt
  • hot_rod
    hot_rod Member Posts: 22,258
    The key is to catch and clean them before they get like this

    IF a fire tube gets completely plugged on the fire side it is almost impossible to flush out. I don’t know if any brush that will go down the tubes?

    This coil type is still cleanable, on the fire side.

    The tradeoff with the coil type is if they scale badly in the water side. That is a tough clean also

    so one cleans easier inside, the other outside😉

    Good quality fill water, yearly or every two year breakdown and  clean, either transfers heat efficiently 

    with fire tube you need some clearance above to service them
    Water coils service from the front
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • mattmia2
    mattmia2 Member Posts: 9,747
    Fire tube has less resistance to water flow and has more water so is more tolerant of low flow conditions.