Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The TRX150C and TRX199C are the two largest TRX combis, both rated 95% AFUE. The 199C jumps to the heavy class: 135 lb with 1 1/4" NPT CH connections, heating input to 197 MBH (LP 192) and 4.8 GPM continuous DHW, against the 150C's 92.8 lb, 120 MBH and 3.5 GPM — with bulletin-restricted 2" venting terms.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | NTI Trinity TRX150C | NTI Trinity TRX199C |
|---|---|---|
| Space-heating input, minimum | 13.2 MBH | 19.7 MBH |
| Space-heating input, maximum | 120 MBH | 197 MBH |
| Efficiency (AFUE) | 95 % | 95 % |
| Turndown ratio | up to 11:1 | up to 11:1 |
| Weight | 92.8 lb | 135 lb |
| Max. equivalent vent length, 2" | 100 ft | 100 ft |
| Max. equivalent vent length, 3" | 150 ft | 150 ft |
| CH water connections | 1" male sweat with adapter | 1 1/4" NPT |
| DHW connections | 3/4" male sweat with adapter | 3/4" NPT |
| DHW capacity at 77°F rise | 3.5 GPM | 4.8 GPM |
| Domestic hot water | Integrated combi (DHW plate) in the appliance | Integrated combi (DHW plate) in the appliance |
The 150C sits on the TRX light chassis (92.8 lb, 1" male sweat CH connections, 3/4" sweat DHW connections), while the 199C moves to the heavy class: 135 lb, 1 1/4" NPT CH connections and a 3/4" NPT DHW connection. Both are rated 95% AFUE.
Heating input climbs from 13.2 to 120 MBH on the 150C to 19.7 to 197 MBH on the 199C (LP: 19.2 to 192 MBH), and NTI rates continuous DHW at 3.5 GPM for the 150C and 4.8 GPM for the 199C at a 77°F rise. The 199C's DHW rating is the strongest in the TRX combi line.
The 199C costs more than weight and piping class: its 19.7 MBH minimum fire is the highest in the TRX series, and its 2" venting terms follow NTI technical bulletin 2022-10-26, so 3" pipe to 150 ft per side is the planning figure. It belongs in larger homes and small multi-suite plants whose heat and hot-water calculations both approach its ratings.
NTI Boilers
The NTI Trinity TRX150C is the mid-size TRX combi: space heating at 13.2 to 120 MBH input and 3.5 GPM continuous DHW at a 77°F rise, rated 95% AFUE in a 92.8 lb wall-hung boiler.
NTI Boilers
The NTI Trinity TRX199C is the flagship TRX combi: space heating at 19.7 to 197 MBH (LP 19.2 to 192 MBH) with 4.8 GPM continuous DHW at a 77°F rise, rated 95% AFUE at 135 lb with 1 1/4" NPT CH connections.
4.8 GPM continuous at a 77°F rise, against 3.5 GPM on the TRX150C — the highest DHW rating in the TRX line.
It moves from the light chassis' 1" sweat CH connections to 1 1/4" NPT, and its 3/4" DHW connection is NPT rather than sweat, matching the larger near-boiler flow rates.
When the heat-loss calculation is well below 150 MBH. Its 19.7 MBH minimum fire and heavier 135 lb chassis are only justified when heating and DHW demand genuinely approach its range.
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.