IBC Technologies · SL Series G3 Commercial
IBC SL 40-399 G3
The IBC SL 40-399 G3 is the larger commercial SL G3 boiler: 40 to 399 MBH CSA input, 38.4 to 383 MBH output, 96% combustion and 96% thermal efficiency, 4" venting to 200 equivalent feet and an optional 316Ti titanium heat exchanger.
Key figures
- Max input
- 399 MBH
- Max CSA output
- 383 MBH
- AFUE
- —
- Min input
- 40 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
IBC SL 40-399 G3 in practice
The SL 40-399 G3 covers 40–399 MBH CSA input (11.7–117 kW) and 38.4–383 MBH output (11.2–112 kW). IBC rates it at 96% combustion efficiency and 96% thermal efficiency to ANSI/AHRI-1500; no AFUE is published for this size. It is documented with the SL 26-260 G3 in the commercial I&O manual 120-270E12.
The 399 carries a 4" flue and 4" combustion-air connection, both Schedule 40, with 200 equivalent feet per side and direct-vent or indoor air supply. It weighs 240 lb (110 kg) empty, holds 6.66 USG (25.2 L) and accepts up to 45 USgpm (170 Lpm) with a 20 USgpm (76 Lpm) minimum. Maximum operating pressure is 80 psig (551 kPa), and IBC supplies a 30 psig relief valve.
An optional 316Ti titanium-enhanced heat exchanger is available on this model; the commercial specification table covers the standard and Ti versions in one column. Network features match the rest of the commercial SL G3 line: up to 24 boilers and 9.5 MMBtu/h, 240:1 turndown at 24 x 399, four zone pumps, DDC 0-10 VDC or 4-20 mA and an up-to-10-year commercial heat-exchanger warranty.
Best suited to
- Commercial buildings needing up to 383 MBH output from one wall-hung boiler
- Plants planning a 24-boiler, 9.5 MMBtu/h network
- Projects specifying the optional titanium heat exchanger for the 399
Applicability and support
- Model number
- SL 40-399G3
- 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 IBC Technologies. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| CSA input, minimum | 40 MBH | 11.7 kW |
| CSA input, maximum | 399 MBH | 117 kW |
| Output | ||
| CSA output, minimum | 38.4 MBH | 11.2 kW |
| CSA output, maximum | 383 MBH | 112 kW |
| Efficiency | ||
| Combustion efficiency | 96 % | No AFUE is published for this model. |
| Thermal efficiency (ANSI/AHRI-1500) | 96 % | |
| Domestic hot water | ||
| Domestic hot water | Heating boiler; IBC lists DHW opt-out priority for multi-boiler systems | |
| Venting and air | ||
| Flue material | 4" Schedule 40 / rigid PPs | IBC's page also lists PVC/CPVC/PPs approval. |
| Max. equivalent vent length, each side | 200 ft | |
| Air intake | Direct vent or indoor supply | |
| Physical and connections | ||
| Weight (empty) | 240 lb | 110 kg |
| Heating surface area | 36.56 ft² / 3.40 m² | |
| Pressure vessel water content | 6.66 USG / 25.2 L | |
| Water connections | 1 1/2" NPT-M | |
| Gas connection | 3/4" NPT-F | |
| Relief valve & air vent | 3/4" NPT-F | |
| Condensate connection | 3/4" hose | |
| Electrical | ||
| Power use at full fire (less pumps) | 190 W | 120 V / 60 Hz. |
| Operating limits and other | ||
| Heat exchanger option | Optional 316Ti titanium-enhanced heat exchanger | IBC lists the SL 40-399 G3 Ti as an option in the same specification-table column as the standard 40-399. |
| Maximum boiler flow rate | 45 USgpm / 170 Lpm | |
| Minimum boiler flow rate | 20 USgpm / 76 Lpm | |
| Max. operating water pressure | 80 psig | 551 kPa; ships with a 30 psig pressure relief valve. |
| Minimum water pressure | 8 psig | 55 kPa. |
| Fuel | Natural gas or propane | CSA input is rated for natural gas or propane on IBC's commercial specification table. |
| Gas supply pressure | 4 – 14 in. w.c. | |
| Ambient temperature | 32 – 122 °F | 0 – 50°C. |
| Minimum water temperature | 34 °F | 1°C. |
| Max. water temperature (electronic hi-limit) | 190 °F | 88°C; lockout limit 201°F / 94°C. |
| Max. ΔT supply/return | 40 °F | 22°C electronic fence. |
| Altitude rating | 0 – 12,000 ft | 3,658 m ASL. |
Manuals
Alerts documented for this model
- Ignition Trials Exceeded
- Water High Limit
- Low Water Cutoff
- Interlock 1 or 2 Open
- Vent High Limit
- Max. delta T Exceeded
- Low RPM / Air Flow
- Module High Current
- Low Module Current
- Low Water Pressure
- Inlet Pres. Sensor
- See: Status > SIM menu > Status
- Roll Out Switch
- Controller Board
- No Boilernet Comm
- No MAC address
- [Vent High Pressure]
- Flame Signal / Vent Block
- Reversed Flow
- Temp. probe error
- Unhandled error code
- Blank – screen dark
- Service mode after update
- Water High Limit / Low Water Cutoff won't clear
- Outlet Limited
- Remote offline
- Unoccupied
- Summer
- Failsafe Setpoint
- Sensor
Frequently asked questions
Is the SL 40-399 G3 rated by AFUE?
No. IBC publishes 96% combustion and 96% thermal efficiency (ANSI/AHRI-1500) for this model; 95% AFUE is published for the smaller SL 26-260 G3.
What is the titanium option?
IBC lists an optional 316Ti titanium-enhanced heat exchanger for the SL 40-399 G3. The commercial specification table presents the standard and Ti versions in the same column.
How much vent can the 399 use?
200 equivalent feet of 4" Schedule 40 or rigid PPs per side, with direct-vent or indoor air supply.
Questions about the IBC SL 40-399 G3?
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
- IBC SL 40-399G3 — model page (Canada) · accessed September 9, 2026
- IBC Technical Information Portal — SL G3 commercial specification table · accessed September 9, 2026
- IBC SL Series — series page (Canada) · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.