Rinnai Error Code 10: Air supply or exhaust blocked / condensate trap full (Tankless)

Updated October 13, 2026 · by Aurora Star Tech Inc.

Rinnai error code 10 on a tankless water heater means: Air supply or exhaust blocked / condensate trap full. It is also called Rinnai diagnostic code 10.

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

Homeowner? What Rinnai code 10 means for you

Stop and call Your tankless water heater is reporting: Air supply or exhaust blocked / condensate trap full. This code is a safety shutdown. Turn the tankless water heater off and call a licensed technician. Do not keep resetting it. If you smell gas, leave the house and call your gas utility or 911 from outside.

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.

Call (647) 657-2977 Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Rinnai error code 10 mean?

The unit detects restricted combustion air intake or exhaust. On SENSEI and SENSEI RX/CX units, it also triggers when a blocked condensate drain backs up into the internal trap.

Applies to: SENSEI, SENSEI RX/CX and non-SENSEI tankless (condensate trap check: SENSEI and SENSEI RX/CX only)

Common causes of Rinnai code 10

Clogged or frozen condensate drain line backing up the internal trap (SENSEI, SENSEI RX/CX)
Dirty inlet air filter
Vent installed wrong: unapproved materials, poorly seated or unsealed joints, too long, bad clearances

A technician checks these and 5 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 10

Show all 89 models

C199e C199i CU160e CU160i CU199e CU199i CX160i CX199i CXP160i CXP199i R50LSi R63LSe2 R75LSe R75LSi R94LSe R94LSi R98LSe R98LSe-ASME R98LSi R98LSi-ASME RC80e RC80i RC98e RC98i RE140e RE140i RE160e RE160i RE180e RE180i RE199e RE199i REP160e REP160i REP199e REP199i RH180 RL75e RL75e(A)RL75i RL75i(A)RL94e RL94i RLX94i RSC160e RSC160i RSC199e RSC199i RU80e RU80i RU90e RU98e RU98i RU130e RU130i RU160e RU160i RU180e RU180i RU199e RU199i RUC80i RUC90i RUC98i RUCS65i RUCS75i RUR98e RUR98i RUR160e RUR160i RUR199e RUR199i RUS65e RUS75e RX130i RX160i RX180i RX199i RXP160i RXP199i V53De V53e V65e V65i V75e V75i V94e V94i V94Xi

Other Rinnai Tankless codes

Code	Meaning
02	Burner did not operate during freeze protection
03	Power interrupted during bath fill
05	Bypass flow control device fault
07	Circulation flow rate below 2.1 GPM
11	No ignition
12	Flame failure
13	Combustion fault
14	Thermal fuse or overheat sensor tripped
15	Venturi control fault
16	Outlet water over-temperature safety shutdown
17	Venturi blockage
18	Gas valve air/fuel adjustment limit reached

All Rinnai Tankless Water Heater error codes →

Rinnai code 10: homeowner questions

What does Rinnai code 10 mean?

Air supply or exhaust blocked / condensate trap full. The unit detects restricted combustion air intake or exhaust. On SENSEI and SENSEI RX/CX units, it also triggers when a blocked condensate drain backs up into the internal trap.

Is it safe to keep using my tankless water heater with code 10?

No. Code 10 is a safety shutdown, so keep the tankless water heater off until a licensed technician has checked it.

Can I reset Rinnai code 10 myself?

Do not keep resetting it. Repeated resets can hide a safety problem; a licensed technician needs to find the cause.

Who can fix Rinnai code 10 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

No hot water All brands · Tankless Water Heater
Water temperature fluctuates All brands · Tankless Water Heater

Source: Rinnai Troubleshooting TWH Diagnostic Codes (100000652), p.12–15. 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.