Rinnai Error 90: Combustion / Venting Abnormality
The unit has detected an abnormal combustion or venting condition. We diagnose and repair it across Greater Vancouver — same-day and after-hours.
The unit has detected an abnormal combustion or venting condition.
Rinnai fault codes can vary slightly 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 Rinnai error 90
- Blocked or restricted venting
- Poor combustion (dirty burner)
- Incorrect gas pressure
- Failing fan
What you can safely check
- Check the vent terminal is clear
- Make sure CO alarms are working
- Stop using if you suspect a combustion problem
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 90usually leaves you without heat or hot water and can indicate a safety-related fault. Don't keep resetting it — call for priority after-hours Rinnai repair.
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Parts often behind Rinnai error 90
Genuine Rinnai parts we supply and professionally install — never for DIY.
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Rinnai Error 90 Repair Across Metro Vancouver
Frequently Asked Questions
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Licensed Rinnai diagnosis and repair with genuine parts — same-day and after-hours across Greater Vancouver.
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