Rinnai Tankless Water Heater Error Code 11: Meaning & How to Fix It

By the ErrorCodePro Editorial Team · Last reviewed October 20, 2026

Rinnai tankless water heater error code 11 means: The burner didn't ignite. [1] Keep using it? No hot water until it's resolved. Don't keep resetting it.. Start with the owner checks below, beginning with: open all gas valves.

Smell gas? Leave the building now. Do not touch light switches, phones or appliances inside. Call your gas utility or 911 from outside. CO alarm sounding or headache, dizziness or nausea? Get everyone outside and call 911. Gas valves, burners, venting and wiring are for a licensed technician only. See our safety policy.

Quick facts

Code	11
Also shown as	None listed by the manufacturer
Brand / appliance	Rinnai tankless water heater (sensei and non-sensei tankless water heaters)
System	Heating
Official meaning	The burner didn't ignite. [1]
Keep using it?	No hot water until it's resolved. Don't keep resetting it.
DIY-safe?	Owner checks only (listed below)
Support	Rinnai support, 1-800-621-9419

On this page: Meaning · Steps · Parts · When to call a technician · Related codes · FAQ

What error code 11 means on a Rinnai tankless water heater

The burner didn't ignite. [1]

This is a heating code. Codes and wording can vary by model, so check your owner's manual for your model number.

How to fix Rinnai tankless water heater error code 11 (safe owner checks)

Owner checks only: on heating, cooling and water-heating equipment, limit yourself to reading the code and checking the thermostat, breaker and service switch, air filter, condensate drain, that the gas supply valve is open (no disassembly) and that vent terminals are clear of snow or debris. Reset power only if your manual allows it.

Safety first: disconnect power before you remove any panel or reach into the sump or drum. Do not touch wiring, the control board or the motor. If you see water near electrical parts, stop and call a technician. These steps are based on Rinnai's published guidance [1], rewritten for clarity.

Open all gas valves. Make sure all gas valves on the system are open (no disassembly).
Propane users. Make sure the propane tank has gas.

Parts that may be involved

Exact parts depend on your model number. This page lists part types only, never part numbers.

No specific part is implied by the manufacturer's guidance for this code.

When to call a technician

New installs: air in the gas line, gas type or inlet pressure must be checked by a professional
Gas pressure, gas valve, igniter, flame rod, venting or combustion problems: licensed plumber or gas technician
Gas valves, burners, igniters, flame sensors, venting/flue or CO concerns: licensed HVAC technician or plumber
Refrigerant work: EPA 608-certified technician only
Smell of gas: leave and call the gas utility or 911
Anything involving wiring, the control board, the motor or the water valve electrics
The appliance is under warranty: contact Rinnai support, 1-800-621-9419 first

Frequently asked questions

What does error code 11 mean on a Rinnai tankless water heater?

Rinnai lists 11 as follows: The burner didn't ignite.

Is it safe to keep using the tankless water heater with 11?

No hot water until it's resolved. Don't keep resetting it..

Can I fix Rinnai tankless water heater error 11 myself?

Only with the owner checks on this page, starting with: open all gas valves. If it persists, call a technician or Rinnai support, 1-800-621-9419.

Sources

https://media.rinnai.us/salsify_asset/s-3e3cd69f-0edc-4b85-8d6d-93b39057fab5/100000652-Troubleshooting%20TWH%20Diagnostic%20Codes.pdf (official)

Last reviewed: October 20, 2026. ErrorCodePro is not affiliated with Rinnai.