Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The TFTN500 and TFTN600 are the two smallest floor-mounted TFTN models and share the same 575 lb with-water chassis, 12.5 gallons of water content, 2" water connections, 1" gas connection and 4" venting. The 600 steps input from 50–500 to 60–600 MBH, heating capacity from 489 to 585 MBH and the Net AHRI rating from 425 to 509 MBH, while thermal efficiency eases from 98% to 97.8%.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | NTI Trinity TFTN500 | NTI Trinity TFTN600 |
|---|---|---|
| Input, minimum | 50 MBH | 60 MBH |
| Input, maximum | 500 MBH | 600 MBH |
| Thermal efficiency | 98 % | 97.8 % |
| Heating capacity | 489 MBH | 585 MBH |
| Net AHRI rating | 425 MBH | 509 MBH |
| Weight | 575 lb | 575 lb |
| Water content | 12.5 gal | 12.5 gal |
| CH water connections | 2" NPT | 2" NPT |
| Gas connection | 1" NPT | 1" NPT |
| Domestic hot water | Heating-only; pair with an indirect tank or separate water heater | Heating-only; pair with an indirect tank or separate water heater |
Both boilers are floor-mounted, heating-only TFTN models on the same physical class: 575 lb with water, 12.5 gallons of water content, 2" male NPT water connections, a 1" male NPT gas connection and 4" inlet and exhaust runs to 150 ft per side. NTI rates the floor models by thermal efficiency rather than AFUE — 98% on the TFTN500 and 97.8% on the TFTN600.
The published differences are range and output: the 500 fires 50 to 500 MBH with a 489 MBH heating capacity and a 425 MBH Net AHRI rating, while the 600 fires 60 to 600 MBH with a 585 MBH heating capacity and a 509 MBH Net AHRI rating. The minimum fire also rises from 50 to 60 MBH, which keeps the larger model honest only when the load calculation genuinely needs its ceiling.
Both sizes run on natural gas or propane with NTI's TFTN500–850 LP conversion instructions, and both are documented in the TFTN500–850 I&O manual. For a commercial plant the deciding input is the demand calculation: loads under about 500 MBH keep the higher-rated 500, while demand that approaches 600 MBH justifies the step.
NTI Boilers
The NTI Trinity TFTN500 is the smallest floor-mounted TFTN: 50 to 500 MBH input at 98% thermal efficiency, with a 489 MBH heating capacity and a 425 MBH Net AHRI rating, weighing 575 lb with water on 2" NPT water connections with 4" venting to 150 ft.
NTI Boilers
The NTI Trinity TFTN600 lifts the floor-mounted TFTN to a 600 MBH ceiling: 60 to 600 MBH input at 97.8% thermal efficiency, a 585 MBH heating capacity and a 509 MBH Net AHRI rating, sharing the 575 lb with-water weight and 2" water connections of the TFTN500.
Input rises from 50–500 to 60–600 MBH, heating capacity from 489 to 585 MBH and the Net AHRI rating from 425 to 509 MBH; thermal efficiency eases from 98% to 97.8%. Weight, water content, connections and venting are identical.
Yes — both weigh 575 lb with water with 12.5 gallons of water content, 2" NPT water connections and 4" venting to 150 ft per side, per the NTI product page.
From the plant-demand or heat-loss calculation: the 500 delivers to 500 MBH at the higher 98% thermal rating, and the 600 earns its place when demand approaches its 600 MBH ceiling.
A consultation includes a heat-loss review so the size is right the first time.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
Facts checked September 8, 2026. Last updated September 8, 2026. Technical reviewer: not yet assigned.