Noritz error code 11: ignition failure, causes and fixes

Code 11 is the most common Noritz code. The remote shows 11 instead of the temperature, and the water runs cold.

What to check first

1. Make sure the gas is on at the meter and at the valve to the heater, and that other gas appliances work.
2. On propane, check the tank level.
3. Check the outside vent terminal for blockage.
4. Turn the unit off and on at the remote, then open a hot tap.

Common causes

Noritz points to gas supply problems, airflow problems and debris on the ignition plug. A technician will check that the unit and gas type match, measure gas pressure with a manometer, and test the voltage to the ignition plug.

When to call a contractor

Call a licensed contractor if code 11 returns after you have confirmed the gas supply is on, the vent terminal is clear and the unit has been reset. Measuring gas pressure and testing the ignition plug are jobs for a technician.

Draining for winter

If you are draining the heater for winter or a long absence, a code 11 can appear simply because there is no water flow. That is expected.