Equipment error code

Rinnai code 11

Code 11 — no ignition. The unit failed to establish flame after the ignition sequence.

Equipment: water heater
Brand: Rinnai
Source checked: 2026-03-01

What this code means

Code 11 — no ignition. The unit failed to establish flame after the ignition sequence.

Source: Rinnai Tankless Water Heater Operation Manual — Error Code 11 · checked 2026-03-01

Which models show it

Rinnai RL, RU, RUR, and RX tankless gas water heaters with digital controllers.

What is actually happening

Controller shows 11; no hot water. May hear fan and clicks without burner light.

Is it safe to keep running?

Do not keep opening hot taps to force ignition.

Shut it down when

Gas smell or code 11 twice after reset.

What a homeowner can safely check

Gas on; meter paid and other appliances work.
Clean inlet air filter per Rinnai schedule.
Check exhaust for blockages.
Power cycle unit once.

When to stop

Gas odor.
11 returns immediately.

Likely causes ranked

1. Gas supply issue or closed valve
How a tech confirms: Pressure test static and dynamic.
Typical repair: $175–$425 · Water Heater Replacement cost guide
2. Dirty ignition plug or flame rod
How a tech confirms: Inspect electrodes; clean or replace.
Typical repair: $180–$395 · Water Heater Replacement cost guide
3. Blocked vent or improper slope
How a tech confirms: Vent inspection per Rinnai manual.
Typical repair: $200–$575 · Tankless Water Heater Conversion cost guide
4. Failed gas valve or PC board
How a tech confirms: Rinnai service tool diagnostics.
Typical repair: $450–$1,000 · Tankless Water Heater Conversion cost guide

Is this the end of this unit?

Major board failure on Rinnai past 10 years — compare new RU series installed quote.

How to clear the code

On/off power; ensure gas and vent OK; single hot water demand.

Why clearing is not fixing it: Code 11 until ignition components or gas supply fixed.

Which trade to call

Call a licensed plumber who works on water heater equipment. Gas, refrigerant, and combustion faults are not general handyman jobs.

How to find a good plumber

Before you sign a contract for this job, use our guide on how to find a good plumber: verify the licence at the state board, compare three itemized quotes on the same scope, and put permit responsibility and change-order rules in writing.

Read the plumber hire guide Check if your quote is fair Verify licences by state

More codes from this brand

Code 12 — flame failure

Symptom guide: No Hot Water

FAQ

Rinnai code 11?

No ignition — failed to light burner.

Code 11 after propane tank change?

Purge air from line — if persists, check regulator sizing.

Filter and code 11?

Blocked air filter can prevent proper combustion air — clean per manual.

Code 11 repair cost?

$175–$1,000 depending on gas, electrodes, or board.

11 vs Rheem code 1?

Equivalent ignition failure codes on different brands.

Source

Source — Rinnai Tankless Water Heater Operation Manual — Error Code 11. Checked 2026-03-01.