Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The TRX150 and TRX199 are the two largest heating-only TRX boilers, both 95% AFUE on 1 1/4" NPT connections. The 199 fires 19.7 to 197 MBH (LP 19.2 to 192 MBH) against the 150's 15 to 150 MBH, weighs 130 lb instead of 115, and its 2" venting terms follow NTI technical bulletin 2022-10-26.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | NTI Trinity TRX150 | NTI Trinity TRX199 |
|---|---|---|
| Input, minimum | 15 MBH | 19.7 MBH |
| Input, maximum | 150 MBH | 197 MBH |
| Efficiency (AFUE) | 95 % | 95 % |
| Turndown ratio | up to 11:1 | up to 11:1 |
| Weight | 115 lb | 130 lb |
| Max. equivalent vent length, 2" | 100 ft | 100 ft |
| Max. equivalent vent length, 3" | 150 ft | 150 ft |
| CH water connections | 1 1/4" NPT | 1 1/4" 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 heating-only TRX models are rated 95% AFUE with 1 1/4" NPT CH connections and the same 3/4" NPT gas connection. NTI publishes the 150 at 15 to 150 MBH and the 199 at 19.7 to 197 MBH on natural gas, with the LP range of the 199 reading 19.2 to 192 MBH.
The 199's minimum fire of 19.7 MBH is 4.7 MBH above the 150's 15 MBH floor, which matters in mild-weather operation: a house whose load sits comfortably under 150 MBH will spend more time near minimum fire on the 199. Its 2" venting terms also follow NTI technical bulletin 2022-10-26, so installations are planned on 3" pipe to 150 ft per side.
Domestic hot water is external on both, via an indirect tank or separate water heater. The 199 is for buildings whose heat-loss and recovery calculations genuinely approach its 197 MBH ceiling — large homes and small multi-suite plants — while the 150 covers mid-size detached houses with a lower minimum fire and unrestricted 2" venting.
NTI Boilers
The NTI Trinity TRX150 is the 95% AFUE heating-only TRX for larger homes: 15 to 150 MBH input, stepping up to 1 1/4" NPT CH connections and 115 lb, with 2" venting to 100 ft or 3" to 150 ft per side.
NTI Boilers
The NTI Trinity TRX199 is the largest heating-only TRX: 19.7 to 197 MBH input on natural gas (19.2 to 192 MBH on LP) at 95% AFUE, weighing 130 lb with 1 1/4" NPT CH connections and 3" venting to 150 ft per side.
Yes. NTI lists the TRX199 at 19.7 to 197 MBH on natural gas and 19.2 to 192 MBH on propane — 5 MBH less at the top of the range.
NTI's page lists 2" runs to 100 ft but marks the 2" terms per technical bulletin 2022-10-26, so the 3" route to 150 ft per side is the planning figure.
Only if the heat-loss calculation and hot-water recovery approach 197 MBH. The 199's 19.7 MBH minimum fire makes it a poor match for loads the TRX150 can carry.
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 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.