Navien Error E109: Exhaust / Vent Overheat
An exhaust over-temperature or venting fault has shut the unit down. We diagnose and repair it across Greater Vancouver — same-day and after-hours.
An exhaust over-temperature or venting fault has shut the unit down.
Navien fault codes can vary by model and series. Use this as a guide — the same code can have more than one cause. Our Technical Safety BC–licensed technicians read the code, confirm it against your unit's manual, and diagnose the true cause before any repair.
Likely causes of Navien error E109
- Blocked vent
- Scaled heat exchanger
- Combustion fault
What you can safely check
- Check the outside vent terminal is clear of snow, leaves and debris.
- Ensure CO alarms work
Beyond these checks, do not open the unit or touch gas/electrical parts — BC law requires a licensed gas fitter. Call us for a proper diagnosis.
Error E109 usually leaves you without heat or hot water and can indicate a safety-related fault. Don't keep resetting it — call for priority after-hours Navien repair.
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Parts often behind Navien error E109
Genuine Navien parts we supply and professionally install — never for DIY.
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Navien Error E109 Repair Across Metro Vancouver
Related Navien Venting & Combustion Codes
Frequently Asked Questions
Fix Navien Error E109 Today
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