Can I fix Rinnai code 25 myself?

Start with these safe checks: Make sure the condensate pump is plugged in and has power. Check that the drain line isn't clogged or frozen and empties freely. If the pump runs and the line is clear, have a technician check the wiring and trap.

When should I call a technician for code 25?

If the pump runs and the line is clear, have a technician check the wiring and trap. Smell gas? Leave right away, don't touch light switches or phones inside, and call your gas utility or 911 from outside. Never open a gas valve, burner, gas line, vent or flue connection, or bypass a safety switch. Repeated lockouts, scorching, soot, or a CO alarm mean shut it off and call a licensed gas technician.

Rinnai Tankless Water Heater Error Code 25: Condensate pump error…

What 25 means

Condensate backed up and tripped the float (safety) switch, or the condensate pump stopped working.

Likely causes

Clogged or frozen condensate drain line
Condensate pump unplugged or failed

Safe first checks

Make sure the condensate pump is plugged in and has power.
Check that the drain line isn't clogged or frozen and empties freely.

When to stop

If the pump runs and the line is clear, have a technician check the wiring and trap.

Checked against: Rinnai: Troubleshooting Tankless Water Heater Diagnostic Codes (100000652). Codes can differ by model and year, so confirm with your owner's manual.