NTI Trinity FTVN 3 09 — Flame Detection While Burner is Off
3 09
Flame detection while burner is off. Flame was detected while the burner is off; likely causes are a damaged flame probe or flame probe wire, water damage, a flooded combustion chamber, and a PCB internal fault. The table classifies it as Blocking (Manual Reset).
Applies to
This sensor fault code is displayed by the FTVN Series II control on FTVN Series II models (FTVN085, FTVN110, FTVN150, FTVN199 and combis FTVN110C, FTVN150C, FTVN199C), as documented in FTVN Series II Installation Startup Maintenance Instructions, doc 420012001400 Rev 10, Part 13-B Boiler Error Codes (420012001400 Rev 10). Codes can differ between controller generations, so always check the manual that matches your unit.
- NTI Boilers Trinity FTVN
- NTI Trinity FTVN085
- NTI Trinity FTVN110
- NTI Trinity FTVN150
- NTI Trinity FTVN199
- NTI Trinity FTVN110C
- NTI Trinity FTVN150C
- NTI Trinity FTVN199C
Controller: FTVN Series II control. Source manual: 420012001400 Rev 10 (2024-06-15).
Why a code is not a diagnosis
A sensor code usually means the sensor, its wiring or its mounting is faulty; the physical condition the sensor measures (temperature, pressure, flow) may be perfectly normal.
Safe things to observe
- Note the code; there is no homeowner-accessible check for sensor circuits.
- If the appliance still runs, watch whether the code returns and report it when you call.
Do not
- Do not open the appliance to test or replace sensors yourself.
How professional service helps
- A technician measures the sensor and harness against the manual's values and replaces the faulty component.
- Combustion and safety devices are verified with an analyser and the manufacturer's procedure after any repair.
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.
Flame sensor (flame rod)
The flame sensor is the small rod that proves a gas boiler's burner is actually lit before the control will keep the gas valve open.
What a technician checks →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 →Control board / PCB
The control board — also called the PCB, or printed circuit board — is the boiler's main computer.
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 NTI Boilers Trinity FTVN.
Frequently asked questions
Can I clear this code myself?
Clearing a code without fixing its cause usually just brings it back. Note the code, check the safe items on this page, then call a licensed technician. If your appliance manual describes a user reset for this exact code and it stays away, no call may be needed.
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
- FTVN Series II Installation Startup Maintenance Instructions, doc 420012001400 Rev 10, Part 13-B Boiler Error Codes · 420012001400 Rev 10 · accessed September 7, 2026
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.