Rinnai · Water heater
Code 79 Freeze protection / condensate issue
What this code means
Freeze-protection components have activated, or a condensate drainage issue has been detected on condensing models.
Most likely causes
- Freezing temperatures triggering built-in freeze protection
- Condensate drain line frozen or blocked
What to try first
Confirm the unit's freeze-protection power supply hasn't been disconnected, especially after any electrical work nearby.
Safety note: if this code returns after one clean reset, stop resetting it — repeated lockouts usually mean a real fault that needs a licensed technician. Never bypass a safety switch.
FAQ
What does Rinnai error code Code 79 mean?
Freeze protection / condensate issue. Freeze-protection components have activated, or a condensate drainage issue has been detected on condensing models.
Can I fix Rinnai code Code 79 myself?
Usually not. Confirm the unit's freeze-protection power supply hasn't been disconnected, especially after any electrical work nearby. If the code returns after one reset, it needs a licensed technician.
What causes Rinnai code Code 79?
The most common causes are: freezing temperatures triggering built-in freeze protection; condensate drain line frozen or blocked.
Other Rinnai water heater codes
All Rinnai water heater error codes →
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This information may contain errors or not apply to your exact model — always double-check it against your appliance's own manual before acting. If there's any chance of a gas, fire, electrical, carbon monoxide, or other safety hazard, stop and call a licensed professional or the appropriate agency (e.g. your gas utility) instead of relying on this page alone.