Noritz Code 11: No Ignition Fix for NR and NRCP Series

Quick Answer

Noritz Code 11 means the water heater tried to ignite three times and failed on all attempts. The most common cause is a dirty or corroded flame rod that cannot sense the flame even when gas is present. Other causes include gas supply that is off or at low pressure, a failed spark igniter, or a faulty gas valve.

In my years of servicing Noritz units, this code usually pops up after a long summer or a period where the heater sat idle. Carbon or oxidation builds up on the sensor, so even if the burner lights, the computer stays blind to it. It's a frustrating error because it leaves you with zero hot water, but nine times out of ten, a simple cleaning of the internal sensors gets the hot water flowing again.

NoritzWaterheaterSeverity: highDifficulty: intermediate78% DIY Success

Time to Fix

30–90 min

Difficulty

intermediate

Parts Cost

$12 – $280

Tools Needed

Phillips #2 screwdriver, Multimeter (with ohms/resistance setting)

What Does the 11 Code Mean?

When your Noritz hits Code 11, it's essentially having a communication breakdown. The igniter might be sparking and gas might be flowing, but if that flame rod doesn't send a micro-amp signal back to the board within seconds, the system locks out for safety. Before you assume the gas valve is shot, we need to look at the health of the combustion chamber.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

Dirty or corroded flame rod preventing flame signal40%

Gas supply off, valve closed, or pressure too low24%

Gas valve solenoid coil failure22%

Failed spark igniter not generating spark14%

Symptoms You May Notice

No hot water at all, and the display is holding steady on Code 11 with no attempt to restart on its own.
You hear a rapid tick-tick-tick clicking for about 5-10 seconds when you turn on the hot tap, and then the unit just gives up and goes quiet.
Unit keeps cycling through ignition attempts and locking out over and over until you manually power it off.
Faint smell of gas near the unit right after a failed start, because unburned gas briefly entered the chamber during the attempt.
Cold water at every single tap in the house, not just one fixture.

Can you reset a Noritz waterheater to clear the 11 code?

Tap the power button on the remote controller off and then back on to clear the code. If the flame rod was dirty and you cleaned it, the unit should fire right up. If it fails again, unplug the unit from the wall for 60 seconds and plug it back in. That hard reset clears the board's temporary memory. After the hard reset, wait about 30 seconds before triggering a hot water call so the board fully initializes.

Tools Required for Diagnosis

Phillips #2 screwdriverMultimeter (with ohms/resistance setting)Fine steel wool (000 or 0000 grade)Combustible gas leak detector

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

ComponentComponent Under Test

Expected Range20–40 ohms

ConditionIf Open (OL) or infinite, replace component.

Replacement Parts

If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.

Part Name	OEM Number	Estimated Price
Flame Rod (Flame Sensor)100001706 · $12–$25	100001706	$12 – $25
Spark Igniter Assembly100001714 · $20–$35	100001714	$20 – $35
Gas Valve Assembly100161840 · $150–$280	100161840	$150 – $280

Frequently Asked Questions

What does Noritz Code 11 mean?

Think of Code 11 as a 'No Start' error. The unit tried to light the burner three separate times and never detected a flame on any of them. It's the heater's way of saying it doesn't want to keep dumping gas into the chamber if it can't verify the gas is actually burning. In the field, I find this is almost always a maintenance issue rather than a part failure, specifically carbon or oxidation buildup on the flame sensor rod. Clean that rod first before you do anything else.

Can I clean the Noritz flame rod myself?

Absolutely, and it should be your first step. Once you get the front cover off, it's just one screw and one wire. Cleaning that rod with a bit of steel wool takes about 15 minutes and saves you a $200 service call. Just be gentle with the ceramic insulator because it'll crack if you drop the rod or overtighten the mounting screw. I've seen guys snap that insulator right off and turn a 15-minute job into a parts order waiting game.

How do I know if the Noritz spark igniter is working?

You should hear a very distinct, rapid tick-tick-tick when you first turn on the hot water. You can usually see the spark through the little glass observation window on the burner box. If you hear clicking and then a 'thump' but no fire, the igniter's doing its job but the gas isn't reaching the spark or the sensor isn't reporting the flame back to the board. No clicking at all? That's an igniter or lead wire problem right there.

Noritz Code 11 vs Code 12, what's the difference?

It's all about timing. Code 11 means the fire never started at all, three attempts and nothing. Code 12 means it started just fine but cut out mid-shower. They share some causes like a dirty flame rod, but Code 12 is way more likely to point to fluctuating gas pressure or an exhaust venting issue that's basically smothering the flame after it lights. If your Code 11 clears but you start seeing Code 12 pop up a few weeks later, start looking at your venting.

How long does gas valve replacement take on a Noritz?

A pro can usually swap it out in about an hour if the valve is truly dead. But since this involves breaking into the gas line, it's not a beginner project. You have to do a proper leak test afterward and know how to do it right. If you've cleaned the rod, confirmed the igniter sparks, and verified gas supply but still have nothing, that's when I'd say call a licensed tech. Don't mess with the gas valve yourself if you haven't done it before.

Is it dangerous to keep resetting a Code 11 over and over?

Yeah, don't do that. Every failed ignition attempt pushes a small amount of unburned gas into the chamber. The board cuts off after three tries specifically to prevent buildup, but if you keep manually resetting and retrying 20 times in a row hoping it'll eventually catch, you're pushing your luck. No hot water is annoying but it's not an emergency. Fix the root cause first, then reset once.

Related Noritz Waterheater Error Codes

Code: HUBNoritz Tankless Water Heater Error Codes: Complete NR and NRCP Series Guide Code: 12Noritz Code 12: Flame Failure During Operation Code: IGN-FAILURENoritz Water Heater Ignition Failure: Causes When No Error Code is Shown Code: RESETHow to Reset a Noritz Tankless Water Heater and Clear Error Codes

Same Fix on Other Brands

Rinnai waterheater11: Rinnai Code 11: No Ignition Navien waterheaterE003: Navien E003 Error Code: Ignition Failure

Models Known to Experience 11 Errors

This repair applies to most Noritz waterheaters with this error code. Common model numbers include:

NRCP199-DV, NRCP111-DV, NR98-DV, NR66-DV, NR711, NRC661-DV, NRC98-DV, NRC111-DV

Written by

Raj Patel

HVAC & Water Systems Specialist · 15 years experience

Last verified for technical accuracy on March 14, 2026