NTI Trinity TFTN500

NTI lists the floor-mounted TFTN500 at 50 to 500 MBH input with 98% thermal efficiency, a heating capacity of 489 MBH and a Net AHRI rating of 425 MBH — a thermal rating rather than an AFUE figure, matching the column treatment the TFTN340 and TFTN399 wall models receive. The boiler weighs 575 lb with water, holds 12.5 gallons, connects on 2" male NPT water pipe with a 1" male NPT gas connection, and vents in 4" pipe to 150 ft each side.

The TFTN500 is the entry size of the floor-mounted branch NTI sells for commercial applications: the same product page that markets the wall-hung 085–399 sizes says the larger 285-to-850 MBH sizes are available for commercial work. For a Lower Mainland building the model is sized from a heat-loss or plant-demand calculation rather than floor area — the 500, with its 50 MBH minimum fire, is the smallest floor step above the 399 MBH wall-hung ceiling — and LP installations follow NTI's TFTN500–850 conversion instructions.