NTI Flue / Air Pressure Fault: Flue or Air-Pressure Fault
What the NTI Flue / Air Pressure Fault fault means, what causes it, and why it's a job for a licensed BC gas technician — not a DIY reset.
Severity
High — needs prompt professional attention
Gas safety first
This fault involves gas, combustion or venting. If you smell gas (rotten-egg odour), hear hissing, or feel unwell, leave the building immediately and call 911 or FortisBC at 1-800-663-9911 from outside. Do not flip switches or relight anything. For all other cases, switch the boiler off and call a licensed gas technician.
What the NTI Flue / Air Pressure Fault fault means
The boiler detected abnormal intake or exhaust conditions and stopped — correct venting is essential for safe combustion.
On NTI TFTN (Trinity Fire Tube), FTVN and TRX condensing boilers, Flue / Air Pressure Fault is a air-pressure / venting fault. It is a protective response — the boiler is telling you something needs attention, and the safe, lasting fix is a proper diagnosis rather than repeated resets.
Symptoms you may notice
- Lockout, often worse in wind, rain or cold snaps
- No heat or hot water
- Boiler tries to start, then faults during purge
Common causes of NTI Flue / Air Pressure Fault
Why this is not a DIY fix
Air-pressure-switch and flue faults are a combustion-safety issue: a blocked, disconnected or leaking vent can spill flue gases — including carbon monoxide — into your home. This must be inspected and corrected by a licensed gas technician, never patched or bypassed.
In British Columbia, gas work must be performed by a TSBC-licensed gas fitter. GasBoilers.ca — a CanroHeat division — sends Red Seal–certified, gas-licensed technicians who diagnose the true cause, repair it correctly, and verify safe operation before they leave.
How our technicians diagnose & repair it
- 1Inspect intake and exhaust venting for blockage, sagging or disconnection
- 2Test the air-pressure switch and its sensing tubes for blockage or condensate
- 3Check the condensate trap and flue for water back-up
- 4Verify safe combustion and draft with analysis before return to service
NTI Flue / Air Pressure Fault — FAQ
What does the NTI Flue / Air Pressure Fault fault mean?
The boiler detected abnormal intake or exhaust conditions and stopped — correct venting is essential for safe combustion. On NTI TFTN (Trinity Fire Tube), FTVN and TRX condensing boilers, this is categorised as a air-pressure / venting fault.
What causes NTI Flue / Air Pressure Fault?
The most common causes are: Blocked or restricted flue termination; Debris or wind-driven rain at a sidewall termination; Disconnected exhaust joint; Fan not reaching target speed. A licensed technician confirms which one applies before any part is replaced.
Can I fix NTI Flue / Air Pressure Fault myself?
No. Air-pressure-switch and flue faults are a combustion-safety issue: a blocked, disconnected or leaking vent can spill flue gases — including carbon monoxide — into your home. This must be inspected and corrected by a licensed gas technician, never patched or bypassed. Repeatedly resetting the boiler without fixing the root cause can be unsafe and can cause further damage. Call GasBoilers.ca at 604-359-1081 for a licensed diagnosis.
Is the NTI Flue / Air Pressure Fault fault dangerous?
It can be. This fault involves combustion, gas or venting. If you ever smell gas, leave the building immediately and call 911 or FortisBC at 1-800-663-9911 from outside. Otherwise, switch the boiler off and book a licensed technician.
How much does it cost to fix NTI Flue / Air Pressure Fault in Greater Vancouver?
Cost depends on the root cause and any parts needed. We start with a flat-rate diagnostic, then quote the repair before any work begins — no surprises. Call 604-359-1081 for current pricing and same-day availability.
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NTI showing Flue / Air Pressure Fault? We'll fix it right.
Licensed, Red Seal–certified gas technicians across Greater Vancouver. Upfront pricing, same-day service available.