12
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Rinnai · Tankless Water Heaters
Flame failure during operation.
Quick Answer
Error code 12 on your Rinnai Tankless Water Heaters means: Flame failure during operation.. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
How to Fix It
1
Confirm gas supply stability.
2
Check vent and intake path.
3
Clean and inspect flame rod.
4
Restart unit and monitor operation.
5
Schedule service if flame loss repeats.
Pro Tip
This issue typically requires professional diagnosis. Attempting this fix without proper training could cause further problems.
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