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Rinnai Error Code 25: Condensate pump failure or clogged drain (Tankless)

Updated · by Aurora Star Tech Inc.

Rinnai error code 25 on a tankless water heater means: Condensate pump failure or clogged drain. It is also called Rinnai diagnostic code 25.

Medium severityTankless Water HeaterNon-SENSEI · RH180 hybrid · SENSEI RX/CX · SENSEI

Homeowner? What Rinnai code 25 means for you

Check, then call Your tankless water heater is reporting: Condensate pump failure or clogged drain. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

Safe things you can check yourself

  • Check that gas reaches the house: other gas appliances work, or the propane tank is not empty.
  • Make sure the heater is plugged in and its breaker is on. In winter, keep the power on: it protects the unit from freezing.
  • Outside, make sure the intake and exhaust pipes or vent cap are not blocked by snow, ice, leaves or a nest.
  • Check that the hot and cold water valves under the heater are fully open.
  • If you have a remote controller, turn it off and on once. If the code comes back, call a technician.

Call (647) 657-2977Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Rinnai error code 25 mean?

Triggered when the condensate float/safety switch closes because condensate has backed up, or when the accessory condensate pump stops working.

Applies to: SENSEI Series; SENSEI RX/CX Series; Non-SENSEI Series

Common causes of Rinnai code 25

  • No power to the condensate pump
  • External condensate pump not working
  • Clogged or frozen drain line

A technician checks these and 3 other possible causes on site before replacing any part.

Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

Rinnai models that use code 25

Show all 89 models

C199eC199iCU160eCU160iCU199eCU199iCX160iCX199iCXP160iCXP199iR50LSiR63LSe2R75LSeR75LSiR94LSeR94LSiR98LSeR98LSe-ASMER98LSiR98LSi-ASMERC80eRC80iRC98eRC98iRE140eRE140iRE160eRE160iRE180eRE180iRE199eRE199iREP160eREP160iREP199eREP199iRH180RL75eRL75e(A)RL75iRL75i(A)RL94eRL94iRLX94iRSC160eRSC160iRSC199eRSC199iRU80eRU80iRU90eRU98eRU98iRU130eRU130iRU160eRU160iRU180eRU180iRU199eRU199iRUC80iRUC90iRUC98iRUCS65iRUCS75iRUR98eRUR98iRUR160eRUR160iRUR199eRUR199iRUS65eRUS75eRX130iRX160iRX180iRX199iRXP160iRXP199iV53DeV53eV65eV65iV75eV75iV94eV94iV94Xi

Other Rinnai Tankless codes

CodeMeaning
16Outlet water over-temperature safety shutdown
17Venturi blockage
18Gas valve air/fuel adjustment limit reached
19Electrical grounding / DC circuit short
21PC board data transfer error
22Gas valve adjustment fault
30Flammable vapor sensor activated or faulty
31Burner thermocouple out of range
32Outlet water temperature thermistor fault
33Heat exchanger thermistor fault
34Combustion air thermistor (Non-SENSEI) / Lime detecting thermistor (RX/CX)
35Tank temperature sensor fault

All Rinnai Tankless Water Heater error codes →

Rinnai code 25: homeowner questions

What does Rinnai code 25 mean?

Condensate pump failure or clogged drain. Triggered when the condensate float/safety switch closes because condensate has backed up, or when the accessory condensate pump stops working.

Is it safe to keep using my tankless water heater with code 25?

It depends on the cause. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

Can I reset Rinnai code 25 myself?

You can try one reset (power off for 30 seconds, then on). If Rinnai code 25 comes back, the cause is still there and a licensed technician should check it.

Who can fix Rinnai code 25 near me?

Aurora Star Tech Inc. repairs Rinnai tankless water heaters in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: Tankless Water Heater No Hot Water: What to Check

Troubleshooting guides

Source: Rinnai Troubleshooting TWH Diagnostic Codes (100000652), p.34. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

Emergency HVAC Service

647-657-2977