NTI Boilers · Trinity TFT (discontinued)
NTI Trinity TFT399
The NTI Trinity TFT399 is a discontinued wall-hung fire-tube condensing boiler: 39.9–399 MBH input with a 380 MBH heating capacity, a 330 MBH Net I=B=R rating and 95.4% thermal efficiency (AFUE not applicable) per the TFT I&O manual (99984535).
Key figures
- Max input
- 399 MBH
- Max CSA output
- —
- AFUE
- 95.4 %
- Min input
- 39.9 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
NTI Trinity TFT399 in practice
The TFT399 is one of the eight wall-hung condensing models in NTI's discontinued Trinity TFT line, documented in the Trinity Tft 60-399 Installation and Operation Instructions (99984535, V.2024-04-08). Table 2-1 lists it at 39.9–399 MBH CSA input modulation with a 380 MBH DOE heating capacity and a 330 MBH Net I=B=R rating. The manual prints 95.4% for this size as thermal efficiency and notes that AFUE is not applicable above 299 MBH.
The model connects with 1-1/2" NPT male water connections and a 3/4" NPT male gas connection, and the manual specifies 4 in vent/air-inlet piping. The discontinued TFT page lists 4" runs up to 100 ft each side, a with-water weight of 250 lb and 6.4 gallons of boiler water content for this size. NTI lists the TFT under Discontinued and describes the current TFTN as built on the same platform with a redesigned control, so TFT owners and technicians rely on the 99984535 manual and the discontinued page's submittals.
Best suited to
- Commercial loads up to 399 MBH where AFUE does not apply
- Plants wanting the largest TFT in the 4" venting class
- Cascade and common-vent installations at the top of the TFT line
Applicability and support
- Model number
- TFT399
- Canadian availability
- historical
- Production status
- discontinued
- ROMA supplies
- Confirmed at consultation
- ROMA services
- Confirmed at consultation
- Warranty
- Not verified
Where ROMA provides on-site service
On-site service is currently offered in Greater Vancouver, BC, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Port Coquitlam, Port Moody, Delta, Langley, Maple Ridge, Abbotsford, Chilliwack, White Rock, Pitt Meadows, Tsawwassen, Anmore, Lions Bay, Belcarra, Bowen Island, Mission. Everything else on this site is reference information you can use anywhere in Canada.
Specifications
Published specifications
Values as published by NTI Boilers. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input, minimum | 39.9 MBH | Per the Trinity Tft 60-399 I&O manual (99984535), Table 2-1; the discontinued TFT page prints the same natural-gas row. |
| Input, maximum | 399 MBH | Per the Trinity Tft 60-399 I&O manual (99984535), Table 2-1; the discontinued TFT page prints the same natural-gas row. |
| Output | ||
| DOE heating capacity | 380 MBH | Per the TFT I&O manual (99984535), Table 2-1. |
| Net I=B=R rating | 330 MBH | Per the TFT I&O manual (99984535), Table 2-1. |
| Efficiency | ||
| Thermal efficiency | 95.4 % | The manual prints 95.4% as thermal efficiency for the TFT340/TFT399 and notes AFUE is not applicable above 299 MBH; the discontinued page repeats 95.4%. |
| Domestic hot water | ||
| Domestic hot water | Heating-only; pair with an indirect tank or separate water heater | |
| Venting and air | ||
| Vent / air-inlet diameter | 4 in | Per the TFT I&O manual, Table 2-1. |
| Vent / air-inlet length | 4" runs up to 100 ft each side | Per the discontinued TFT product page. |
| Physical and connections | ||
| Water connections | 1-1/2" NPT male | NPT male per the TFT I&O manual, Table 2-1. |
| Gas connection | 3/4" NPT male | NPT male per the TFT I&O manual, Table 2-1. |
| Weight, with water | 250 lb | Per the TFT I&O manual, Table 2-1. |
| Boiler water content | 6.4 gal | Per the TFT I&O manual, Table 2-1. |
| Operating limits and other | ||
| Canada altitude derate | 10% derate at 2,000–4,500 ft | Per the TFT I&O manual, Table 2-2. |
| Fuel | Natural gas or propane | The discontinued TFT page prints a separate LP input row identical to the natural-gas row for this size. |
Manuals
- Trinity Tft 60-399 Installation and Operation Instructions, 99984535, V.2024-04-0899984535 · 2024-04-08
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Frequently asked questions
Is the TFT399 still available?
No. NTI lists the TFT series under Discontinued. The current TFTN line is described by NTI as built on the same platform as the TFT with a redesigned control.
What efficiency does the TFT399 have?
The TFT I&O manual (99984535) prints 95.4% for the TFT399 as thermal efficiency and notes AFUE is not applicable above 299 MBH.
What connections and venting does the TFT399 use?
1-1/2" NPT male water connections, a 3/4" NPT male gas connection and 4 in vent/air-inlet piping per the TFT I&O manual's Table 2-1.
Questions about the NTI Trinity TFT399?
Describe what the boiler is doing and get a straight answer about the next step.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
- NTI — TFT Series (Discontinued) · accessed September 9, 2026
- NTI — Discontinued · accessed September 9, 2026
- Trinity Tft 60-399 Installation and Operation Instructions · 99984535 · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.