Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The TFTN285 and TFTN340 are the largest TFTN wall sizes below the 399, and the 340 is a different machine: 39.9 to 340 MBH with a 95.4% thermal-efficiency rating instead of AFUE, in a 25 1/4 inch-wide cabinet at 250 lb with water, stepping to 1 1/2" NPT CH connections and 4" venting.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | NTI Trinity TFTN285 | NTI Trinity TFTN340 |
|---|---|---|
| Input, minimum | 28.5 MBH | 39.9 MBH |
| Input, maximum | 285 MBH | 340 MBH |
| Weight | 180 lb | 250 lb |
| Width | 21.375 in | 25.25 in |
| Height | 34.125 in | 36.5 in |
| Depth | 18.375 in | 18.875 in |
| Max. equivalent vent length | 150 ft | 150 ft |
| CH water connections | 1 1/4" NPT | 1 1/2" NPT |
| Gas connection | 3/4" NPT | 3/4" 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 |
The 285 fires 28.5 to 285 MBH in the 21 3/8 by 34 1/8 by 18 3/8 inch cabinet at 180 lb with water, rated 95% AFUE on 1 1/4" NPT CH connections with 3" venting to 150 ft per side. The 340 fires 39.9 to 340 MBH in a 25 1/4 by 36 1/2 by 18 7/8 inch cabinet at 250 lb with water.
Three specification breaks separate them: the 340 is rated 95.4% thermal efficiency rather than AFUE; its CH connections step up to 1 1/2" NPT; and its venting is 4" only, to 150 ft per side, with no 3" option. Its minimum fire also rises from 28.5 to 39.9 MBH.
Both are heating-only and share the TFTN wall control platform. The 340 is the choice when the plant-demand calculation approaches 340 MBH and the mechanical room can handle a 250 lb wall load with 4" venting; loads within the 285's range keep the lighter, AFUE-rated, 3"-vented model.
NTI Boilers
The NTI Trinity TFTN285 is the 95% AFUE wall-hung TFTN for big houses and light-commercial plants: 28.5 to 285 MBH input, 180 lb with water, in a wider 21 3/8 inch cabinet with 3"-only venting to 150 ft.
NTI Boilers
The NTI Trinity TFTN340 is the first of the two largest TFTN wall models: 39.9 to 340 MBH input, rated 95.4% thermal efficiency rather than AFUE, at 250 lb with water in a 25 1/4 inch-wide cabinet with 4" venting to 150 ft.
NTI publishes 95.4% thermal efficiency for the TFTN340 and TFTN399 in its AFUE/thermal-efficiency column, rather than an AFUE figure for those two sizes.
4" pipe to 150 ft maximum each side, per the NTI product page. There is no 2" or 3" option at this size.
250 lb with water against 180 lb for the TFTN285 — the mounting wall and lifting plan need a contractor's assessment at either size.
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.