Noritz Water Heater Error Code 122: Meaning and Fixes

Noritz error code 122 typically points to a flame detection failure or communication glitch, which you can often resolve by inspecting the flame rod or resetting power.

Table of Contents

What does error code 122 mean on a Noritz water heater?
What usually causes Noritz error code 122 to appear?
What quick fixes should you try first for code 122?
What are the next troubleshooting steps if the error persists?
Which fix matches your specific symptom?
When should you stop and call a licensed technician?
What information should you have ready before calling support?
How can you keep error code 122 from coming back?

What does error code 122 mean on a Noritz water heater?

Error code 122 typically indicates a flame detection failure or a communication error between the display window and the circuit board, depending on your specific model line.

Because error code meanings can vary slightly across different Noritz tankless water heater production years and model lines, you should always confirm the exact definition in your owner’s manual. Generally, it points to either the flame rod failing to detect a stable burner flame or an internal wiring disruption.

Check your specific unit manual because exact definitions for code 122 can differ by model release year.
Many manuals associate this code with flame sensor anomalies during operation or startup ignition sequences.
Certain series use this code to flag a loose connection between the display window and circuit board.
Verify whether your heater experiences complete ignition failure or sudden flame loss after successfully starting.
Inspect the digital control panel to see if the error code appears immediately or only during high hot water demand.

What usually causes Noritz error code 122 to appear?

Common causes include a dirty or carbon-coated flame rod, blocked gas or venting supplies, or loose internal wiring connections.

Over time, combustion residue builds up on the flame sensing rod, preventing it from accurately reading the burner flame. Additionally, minor electrical disruptions, loose harness connections, or restricted intake and exhaust pathways can trigger safety lockouts resulting in this error code.

Soot and carbon buildup coating the surface of the burner flame sensing rod.
Loose or corroded electrical wiring harnesses connecting the display window to the circuit board.
Inadequate gas supply pressure or temporary disruptions coming from your local utility provider.
Obstructed intake air or blocked exhaust venting preventing clean combustion airflow.
A failing internal flame sensor component that requires professional cleaning or complete replacement.

What quick fixes should you try first for code 122?

You can try performing a simple power reset by unplugging the unit and checking external gas and electrical supply connections.

Before attempting any hands-on inspection, always prioritize safety by turning off power at the breaker to prevent electrical shocks. Simple power cycles and basic connection checks can clear temporary system glitches and restore normal communication across the internal circuit boards.

Turn off the power switch and unplug the water heater from the electrical outlet.
Locate the gas supply shutoff valve and ensure it is fully open.
Wait at least sixty seconds to allow internal capacitors to fully discharge.
Plug the water heater back into the electrical outlet and turn power on.
Open a nearby hot water faucet to test if the burner ignites properly.

What are the next troubleshooting steps if the error persists?

If the error remains, you can inspect internal wire harnesses or carefully clean the flame sensing rod using fine sandpaper.

When basic resets fail, the issue often stems from physical component contamination or minor connection slips inside the chassis. Ensure you disconnect power before opening the front cover to examine internal wiring or service delicate flame detection components.

Disconnect the electrical power supply and remove the front metal cover of the water heater.
Inspect the wiring harness running from the display window to the main circuit board for security.
Locate the flame sensing rod near the burner assembly and check for visible soot accumulation.
Gently clean the metal tip of the flame rod using fine abrasive paper until shiny.
Reassemble the unit securely, restore power, and test operation by running a hot water tap.

Which fix matches your specific symptom?

Review this quick reference table to match your immediate appliance symptom with its corresponding troubleshooting solution.

Different operational symptoms indicate distinct underlying failures within your tankless water heater system. Matching your exact observation helps quickly pinpoint whether you need a simple power reset, component cleaning, or professional gas system service. Always cross-reference your specific model manual before proceeding with hands-on repairs.

Symptom	Likely cause / fix
Error appears instantly	Display connection / Reset power
Flame lights then dies	Dirty flame rod / Clean rod
No ignition sound	Gas supply issue / Check valve
Repeated lockout codes	Failing sensor / Call technician

When should you stop and call a licensed technician?

You must stop troubleshooting and call a professional if you smell gas, suspect a gas valve issue, or face complex internal repairs.

Gas appliances carry inherent risks that require specialized training and tools to service safely. Never attempt to service gas valves, burner manifolds, or sealed venting systems yourself if basic cleaning and resets fail to resolve the underlying error code.

Stop immediately if you detect any unusual gas odors around the water heater unit.
Call a licensed professional if troubleshooting involves adjusting the main gas valve or regulator.
Contact support when internal electrical components or circuit boards show signs of physical damage.
Reach out to an expert if the error code returns immediately after cleaning the flame rod.
Engage certified technicians for any complex repairs requiring specialized combustion testing equipment.

What information should you have ready before calling support?

Gather your exact water heater model number, serial number, warranty details, and a clear list of troubleshooting steps already tried.

Having accurate appliance details ready speeds up diagnostic support and ensures technicians bring the correct replacement parts. Check the rating plate on the side of your water heater cabinet to locate the full model and serial identification numbers.

Locate the exact model number printed on the specification label affixed to your water heater.
Note the unique serial number to verify manufacturing dates and active warranty coverage status.
Write down the specific error code displayed on your remote control panel.
Prepare a brief summary of all troubleshooting steps and resets you have already attempted.
Keep your purchase receipt or installation records accessible in case warranty claims are needed.

How can you keep error code 122 from coming back?

Prevent future errors by scheduling annual maintenance, flushing the heat exchanger, and ensuring unobstructed intake and exhaust venting.

Routine preventative maintenance protects your tankless water heater from premature component wear and combustion buildup. Keeping venting pathways clear and servicing internal sensors annually ensures reliable operation and extends the overall lifespan of your appliance.

Schedule professional annual maintenance to inspect and clean internal burners and flame rods.
Flush the heat exchanger regularly to prevent mineral scale buildup and restricted water flow.
Inspect outdoor intake and exhaust vent terminals periodically to clear leaves, snow, or debris.
Test water pressure levels and protect sensitive electronics using a dedicated electrical surge protector.
Consult your owner’s manual for recommended maintenance intervals specific to your local water quality.

Frequently Asked Questions

Can I fix Noritz error code 122 myself without calling a plumber?

You can safely perform basic troubleshooting steps such as power resetting the unit or gently cleaning the flame sensing rod with fine sandpaper. However, if the error persists or involves gas valve components, you must contact a licensed technician to ensure safety and avoid property damage.

What should I do if error code 122 comes back immediately after a reset?

If the code returns instantly, it usually means the flame rod is heavily oxidized or the wiring harness between the display and circuit board is loose. Turn off the power, inspect the internal connections, and clean the flame sensor thoroughly before seeking professional assistance if the issue continues.

Does error code 122 mean my gas supply has been shut off completely?

Not necessarily, but it can indicate low gas pressure or temporary supply interruptions from your utility provider. Check other gas appliances in your home to see if they are functioning properly, and verify that the manual gas shutoff valve beside your water heater is fully open.

Is error code 122 the same across all Noritz water heater model series?

No, error code definitions can vary significantly depending on the specific model line and production year. Certain older or newer series use code 122 to designate flame loss, while others reference a display board communication fault, so always check your specific owner’s manual.

How much does it typically cost to repair a Noritz water heater showing error code 122?

Repair costs vary widely depending on your geographic location and the exact part needing replacement. Basic service calls or cleaning a dirty flame rod are relatively inexpensive, whereas replacing a main circuit board or burner assembly will involve higher parts and labor expenses.

Bottom Line

The best thing to do first is perform a simple power reset by unplugging your water heater for sixty seconds. If the error code remains visible upon restart, inspect the flame sensor rod for carbon buildup or consult your owner’s manual for model-specific definitions.

Sources

Noritz Support Manual
Noritz Owner Guide
Manufacturer Support Page
HVAC Technical Reference