Rinnai · Water heater
Code 25 Condensate drain blocked (float switch tripped)
What this code means
The condensate safety float switch has tripped, almost always because the condensate drain line is blocked or frozen and water is backing up.
Most likely causes
- Clogged condensate drain line
- Frozen condensate line in cold weather
- Condensate trap needs cleaning
What to try first
Check the condensate drain line for a clog or, in freezing weather, ice. Clearing it is often enough to resolve this without a technician visit.
Good news: this one is often fixable without a service call. If it persists after the steps above, have it looked at.
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What does Rinnai error code Code 25 mean?
Condensate drain blocked (float switch tripped). The condensate safety float switch has tripped, almost always because the condensate drain line is blocked or frozen and water is backing up.
Can I fix Rinnai code Code 25 myself?
Often, yes. Check the condensate drain line for a clog or, in freezing weather, ice. Clearing it is often enough to resolve this without a technician visit.
What causes Rinnai code Code 25?
The most common causes are: clogged condensate drain line; frozen condensate line in cold weather; condensate trap needs cleaning.
Other Rinnai water heater codes
All Rinnai water heater error codes →
Other water heater brands: Rheem · Ruud · Navien · Noritz · Takagi · A.O. Smith · Bradford White · State / American · Generic electric · Generic tankless
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.