Triangle Tube Instinct 155C (floor combi)
The Instinct 155C floor combi (INSFS155C) delivers the wall combi's 19.375 to 155 MBH and 4.0 GPM DHW performance in a floor-standing 181 lb cabinet. Discontinued with the November 3, 2025 cessation.
Key figures
- Max input
- 155 MBH
- Max CSA output
- —
- AFUE
- 95 %
- Min input
- 19.375 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Triangle Tube Instinct 155C (floor combi) in practice
The INSFS155C is the floor version of the 155C combi: the same 19,375 to 155,000 BTU/h input at 95% AFUE with an 8:1 turndown, 142 MBH DOE capacity and 123 MBH net AHRI, plus the plate heat exchanger whose DHW performance the product page describes as identical to the wall combi — 4.0 GPM at a 70°F rise.
The floor form factor changes the numbers that matter on site: 181 lb, a 22" x 41" x 22" cabinet, 1" MNPT supply/return connections (1 1/4" FPT with the 548 Caleffi Separator), a 3/4" MNPT gas connection and 3" venting to 100 ft. The DHW side keeps the 150 °F maximum flow temperature, 0.5 GPM minimum flow and 150 psi maximum operating pressure of the combi line. Triangle Tube ceased operations November 3, 2025; this model is documented for the installed base.
Best suited to
- Basement installs that want combi hot water without a wall-mounted unit
- Floor-standing plants needing the 155-class heating range and 4.0 GPM DHW at 70°F
- Mechanical rooms where the 22-inch cabinet footprint fits the floor plan
Applicability and support
- Model number
- INSFS155C
- Canadian availability
- historical
- Production status
- discontinued
- 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 Triangle Tube. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Heating input, minimum | 19.375 MBH | 19,375 to 155,000 BTU/h as printed. |
| Heating input, maximum | 155 MBH | 19,375 to 155,000 BTU/h as printed. |
| Output | ||
| DOE heating capacity | 142 MBH | Per the product-page spec table. |
| Net AHRI rating | 123 MBH | Per the product-page spec table. |
| Efficiency | ||
| Efficiency (AFUE) | 95 % | 95% AFUE per the product-page spec table. |
| Domestic hot water | ||
| Maximum DHW flow temperature | 150 °F (65 °C) | Per the product page. |
| DHW output at 70°F rise | 4 GPM | Performance identical to the wall combi per the product page. |
| DHW minimum flow | 0.5 GPM | |
| DHW maximum operating pressure | 150 psi | |
| Venting and air | ||
| Vent/air diameter | 3" connection; 3-in-1 adapter accepts PVC, polypropylene or stainless steel | Per the product-page spec table. |
| Maximum vent length, 3" | 100 ft | Per the product page and vent supplement 241576. |
| Physical and connections | ||
| Weight | 181 lb | |
| Width | 22 in | |
| Height | 41 in | |
| Depth | 22 in | |
| Supply/return connections | 1" MNPT | 1 1/4" FPT when using the 548 Caleffi Separator, per the product-page footnote. |
| Gas connection | 3/4" MNPT | |
| Operating limits and other | ||
| Fuel | Natural gas or propane | |
| Turndown ratio | 8:1 | |
| Maximum CH flow temperature | 185 °F | Per the product page. |
Manuals
- Instinct Floor (FSB) Installation & Maintenance Manual — Solo 110-155-199 & Combi 155-199242194 Rev. A02 · 2025-09
Alerts documented for this model
Frequently asked questions
Is the floor 155C's hot water output the same as the wall 155C?
The product page states the floor combi's performance is identical to the wall combi's, which publishes 4.0 GPM of DHW at a 70°F rise. What differs is the package: 181 lb in a 22 x 41 x 22-inch floor cabinet.
Which manual covers the INSFS155C?
The floor-series installation manual 242194 (Rev. A02, September 2025) covers the floor solos and combis, including the INSFS155C; the wall manual 241573 covers the wall-hung INS models.
Questions about the Triangle Tube Instinct 155C (floor combi)?
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.
Compare and explore
- Triangle Tube Instinct 110S (wall) vs 155C (floor combi)Comparison
- Triangle Tube Instinct 110S (wall)Same series
- Triangle Tube Instinct 155S (wall)Same series
- Triangle Tube Instinct 199S (wall)Same series
- Triangle Tube Instinct 110S (floor)Same series
- Triangle Tube Instinct 155S (floor)Same series
- Triangle Tube Instinct 199S (floor)Same series
- Triangle Tube Instinct 155C (wall combi)Same series
- Triangle Tube Instinct 199C (wall combi)Same series
- Triangle Tube Instinct 199C (floor combi)Same series
- Instinct series hub
- Buying guide
Sources and verification
- Instinct Floor Installation & Maintenance Manual, 242194 Rev. A02 (09/2025) · accessed September 7, 2026
- Instinct Wall & Floor Vent Supplement, 241576 Rev. A02 (09/2025) · accessed September 7, 2026
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.