Lochinvar FTXL FTX400
The FTXL FTX400 is the entry commercial FTXL: 39.9 to 399 MBH input with 391 MBH gross output and a 340 MBH AHRI net rating at 98.0% submittal thermal efficiency, with 10:1 turndown.
Key figures
- Max input
- 399 MBH
- Max CSA output
- —
- AFUE
- —
- Min input
- 39.9 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Lochinvar FTXL FTX400 in practice
The FTX400 opens the floor-standing FTXL fire-tube line at 399,000 BTU/hr: the I&O ratings table (Series 120) lists 39.9 to 399 MBH input with 391 MBH gross output and a 340 MBH AHRI net water rating, and the FTXL submittal prints 98.0% thermal efficiency with 10:1 turndown. The FTX400N product page adds the 7" SMART TOUCH touchscreen with CON·X·US, ENERGY STAR certification, an ASME H stamp, a 13-gallon nominal capacity (13.2 in the ratings table) and flow rates from 10 to 105 GPM.
The unit connects on 2" water and 1" gas, holds 13.2 gallons, and vents with a 4" air intake and 4" vent in PVC, CPVC, polypropylene or AL29-4C stainless steel to 100 equivalent feet per the submittal, with a common vent kit available. The product page prints a 10-year heat exchanger warranty and a 1-year parts warranty, the submittal lists a 478 lb shipping weight, and Lochinvar's Canada English page is identical to the United States page.
Best suited to
- Light commercial buildings whose design-day load fits under 399 MBH
- Variable-primary systems that suit the fire-tube heat exchanger
- Plants wanting 10:1 turndown from a 4"-vented commercial boiler
Applicability and support
- Model number
- FTX400N
- Canadian availability
- available
- Production status
- current
- ROMA supplies
- Confirmed at consultation
- ROMA services
- Confirmed at consultation
- Warranty
- Series terms
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 Lochinvar. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Heating input, minimum | 39.9 MBH | Per the I&O ratings table. |
| Heating input, maximum | 399 MBH | Per the I&O ratings table. |
| Output | ||
| Gross output | 391 MBH | Per the I&O ratings table. |
| Net AHRI water rating | 340 MBH | Per the I&O ratings table. |
| Efficiency | ||
| Efficiency (thermal) | 98 % | 98.0% thermal efficiency per the FTXL submittal; the FTX400N product page prints 98%. |
| Venting and air | ||
| Air inlet size | 4" | Per the I&O ratings table. |
| Vent size | 4" | Per the I&O ratings table. |
| Venting | Category IV sealed combustion; room air/direct vent in PVC, CPVC, polypropylene or AL29-4C stainless steel | Direct vent to 100 equivalent feet per the FTXL submittal and the product-page feature list; common vent kit available. |
| Physical and connections | ||
| Water content | 13.2 gal | Per the I&O ratings table. |
| Space-heating water connections | 2" | Per the I&O ratings table. |
| Gas connection | 1" | Per the I&O ratings table. |
| Shipping weight | 478 lb | Shipping weight per the FTXL submittal. |
| Height | 53.375 in | Per the Lochinvar product page. |
| Width | 26.5 in | Per the Lochinvar product page. |
Manuals
Alerts documented for this model
- Gas Pressure SW
- Flow Switch/LWCO
- Blocked Drain SW
- Anti-cycling
- Flame Fail Ign
- Flame Sequence
- Outlet ARHL
- Outlet MRHL
- Fan Low/High OR Fan Speed Low/High
- Sensor Open
- Sensor Shorted
- Louver Proving Sw
- Inlet Sensor Fault
- Outlet Sensor Fault
- Outlet Temp Diff
- Flue Sensor Fault
- Flue Temp Diff
- Flue Temp Limit
- Fatal Error
- Memory Error
- Flue Temp High
- Delta T High
- Outlet Temp High
- Rem Ctrl Flt
- Parameters Progr
- Service Blk
- Low 24 vac
- Watch Dog Error
- Write EEProm
- CRC Parameters
- No Error Stored
Frequently asked questions
What is the FTX400's efficiency rating?
The FTXL submittal prints 98.0% thermal efficiency for the FTX400, matching the 98% in the FTX400N product-page spec block; it is ENERGY STAR certified per the page.
What turndown does the FTX400 have?
10:1 per the FTXL submittal — the ratings table lists a 39.9 MBH minimum against the 399 MBH maximum input.
Questions about the Lochinvar FTXL FTX400?
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
- Lochinvar — FTXL Fire Tube Boiler (FTX400N) model page · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.