Noritz Error Code 11

What a no-ignition code means on a tankless heater

Noritz tankless heaters don't have a standing pilot. Noritz's FAQ says modern tankless models use electronic ignition instead. When you open a hot tap, the unit senses flow, runs the fan, sparks the igniter and opens the gas valve. If no flame is detected, the controller shuts the gas off and shows a code.

So an ignition code is a symptom, not a part number. It tells you the burner didn't light. It doesn't tell you why.

Common causes

Noritz's FAQ points owners at four things for any gas heater that isn't heating: gas supply, water flow, power and temperature settings. For a no-light code, gas supply is the one to focus on. The usual suspects on any gas tankless heater:

• A closed gas valve at the heater or the meter.
• A propane tank that's empty, or one that ran dry and left air in the lines.
• A gas line or regulator that can't keep up when the heater fires along with a furnace or range.
• A blocked vent or air intake outside.
• A dirty or damaged igniter or flame sensor inside the cabinet, which is a technician's job.

Safe checks you can do

1. Write the code down and note when it happens: every time, only on the first draw of the morning, or only with several taps open. Noritz's first instruction is to record the code.
2. Check the gas valve on the pipe into the heater. On a typical quarter-turn valve, the handle runs in line with the pipe when it's open.
3. Check other gas appliances. If the stove won't light either, the problem is upstream of the heater. Call the gas utility.
4. Check the propane tank gauge if you're on propane. After a refill, the lines may need air purged before the heater lights reliably.
5. Check power. Noritz lists power among the first checks. Make sure the heater's plug or switch is on and the breaker hasn't tripped.
6. Look at the vent cap and intake outside. Clear snow, leaves or anything that's grown over them.
7. Turn the unit off and back on at the remote, then open one hot tap fully. If it lights and holds, watch it for a few days.

If the code returns right away, stop there. Resetting a heater over and over doesn't fix an ignition fault.

When to call a technician

Book a service visit if the gas is on, the vent is clear and the code keeps coming back. Measuring gas pressure, inspecting the igniter and flame rod, and checking the gas valve all mean opening the cabinet, and Noritz wants a qualified technician doing that.

Noritz phone support is at 1-866-766-7489. Have the model and serial number from the rating plate ready, along with the code history. Noritz also runs a servicer finder on its website for locating a certified tech.

For budgeting, HomeGuide puts tankless water heater repairs at $300 to $1,300 on average. If the heater hasn't been descaled in a while, ask for a flush on the same visit. Our guide on how to flush a tankless water heater explains what's involved.

How this compares with other brands

Most tankless brands use a similar sequence, and several use a similar code number. Rinnai's technical bulletin lists its code 11 as "No Ignition", and its checklist starts with the gas supply too. Our Rinnai code 11 page walks through it. That doesn't prove the Noritz definition, but the owner checks above are safe for any gas tankless heater that won't light.

For more on what goes wrong with these units, see tankless water heater repair.