IBC Technologies · Error codes
IBC SFT-1 n151 — High flue temperature, limited output (notification)
n151
The controller detected a high flue temperature and is limiting burner output to protect the venting, rather than shutting the unit down.
If a carbon-monoxide alarm sounds
- Leave the building immediately and get fresh air.
- Call 911. Do not go back inside until emergency services say it is safe.
- Have every fuel-burning appliance inspected before use.
Only after that, call ROMA about the boiler. Official guidance: Health Canada on carbon monoxide.
Applies to
This notification is shown by the numeric-display touch panel control on Superflow SFT-1 tankless water heaters (SFT 199-1), as documented in IBC Installation & Operating Instructions — SFT 199-1 tankless water heater, doc 84160406, sections 5.3.1–5.3.3.
Controller: numeric-display touch panel control. Source manual: 84160406 (2024-09).
Why a code is not a diagnosis
High flue temperature can come from fouling, wrong fuel setup or combustion settings. The notification does not identify which.
Safe things to observe
- Note the notification and book a service visit if it persists.
- If a CO alarm sounds, leave the building and call 911 from outside.
Do not
- Do not ignore a recurring high-flue-temperature notification.
How professional service helps
- A technician verifies the fuel conversion and combustion readings and cleans the fire side of the heat exchanger.
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.
Parts and service
Parts commonly involved
These parts appear in the documented text for this alert. A code reports a condition, not a failed part — a technician confirms the cause by testing before anything is replaced.
Burner assembly
The burner assembly is where gas and air meet and burn inside a boiler, and its condition decides whether combustion is clean or makes carbon…
What a technician checks →Boiler venting (flue and air intake)
A condensing boiler vents cool, wet flue gases through dedicated plastic pipe that must meet ULC S636 in Canada and the boiler manufacturer's own…
What a technician checks →Flue temperature sensor
The flue temperature sensor — sometimes called the stack or exhaust sensor — measures how hot the gases leaving the boiler are.
What a technician checks →
Service for this alert
- Gas Boiler Repair
Licensed gas technicians from ROMA Heating & Cooling diagnose and repair residential and light-commercial gas boilers across…
Every boiler part explained — what it does, how it fails and what a technician checks.
Documented for IBC Technologies Superflow SFT-1 Tankless.
Boiler locked out? Call with the alert text ready.
The brand, model and this alert are passed along when you request service online, so the technician arrives prepared.
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 Installation & Operating Instructions — SFT 199-1 tankless water heater, doc 84160406, sections 5.3.1–5.3.3 · 84160406 · accessed September 7, 2026
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.