Noritz Tankless Error Codes Explained
What the seven most common Noritz tankless codes report, as Noritz describes them, and which ones need a technician.
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What Is a Noritz Error Code Telling You?
A Noritz error code names the subsystem the unit has stopped on: ignition, flame, outlet temperature, condensate drainage, circuit board settings, unit-to-unit communication, or combustion. The code is where diagnosis starts, not where it ends.
Noritz publishes its own explanation of what it calls the seven most common codes. The descriptions below are taken from that page. Source: Noritz, How to Resolve the Seven Most Common Noritz Tankless Error Codes, accessed 2026-09-22.
We repair Noritz units across Harrisburg City and the surrounding communities, and the brand service page is Noritz Tankless Water Heater Repair in Harrisburg, PA.
What Do the Most Common Noritz Error Codes Mean?
Codes 11 and 12 are ignition and flame faults, 16 is an outlet temperature spike, 29 is condensate drainage, 73 is a circuit board setting, F76 is a communication fault between linked units, and 90 is a combustion abnormality. The table below gives each code as Noritz describes it.
| Code | What Noritz says it means | System involved |
|---|---|---|
| 11 | Ignition failure: the unit is not firing up to heat the water | Ignition and gas supply |
| 12 | A weak flame, with water not being heated properly | Flame and combustion |
| 16 | A sharp spike in outlet water temperature | Temperature control |
| 29 | A problem with condensate drainage | Condensate drain |
| 73 | Improper circuit board settings | Control board |
| F76 | A breakdown in communication between two tankless water heaters using the Quick Connect Cord | Linked units |
| 90 | A combustion abnormality caused by an improper mixture of air and fuel | Combustion air and fuel |
If the code on your unit is not in this table, the installation manual for your model is the authority. Codes beyond these seven are not listed here because Noritz’s page does not describe them.
Which Noritz Codes Need a Technician?
Every code other than a one-off 73 needs a technician, and Noritz’s own guidance for those codes is to contact a licensed contractor.
Why do codes 11, 12 and 90 need a technician?
All three involve the gas supply, the flame or the air-fuel mixture. Correcting any of them means opening the combustion side of a gas appliance, which is technician work.
Why does code 16 need attention quickly?
A sharp rise in outlet water temperature affects what comes out of the tap. Treat a code 16 as a reason to call rather than as a nuisance to clear.
What is involved in fixing code 29?
Code 29 reports a condensate drainage problem. The drain route, its trap and whatever the condensate discharges into are all checked, because a blockage anywhere along that path produces the same code.
What does Noritz say about code 73?
Noritz’s guidance for code 73 begins with a power reset and, if the code persists, a licensed contractor. A code 73 that returns after a reset is reporting a board or settings fault that needs diagnosing.
When does code F76 appear?
Only on installations where two units are linked with the Quick Connect Cord. It reports that the two units have stopped communicating, so the link between them is checked before either unit.
The cross-brand diagnostic process for on-demand units is on Tankless Water Heater Repair in Harrisburg, PA.
What Should You Note Before Calling About a Noritz Code?
Note the code, whether it appeared once or keeps returning, and whether any hot water is reaching the taps. Those three details narrow the visit before anyone arrives.
- Write down the exact code as it appears, including any letter prefix such as the F in F76.
- Note when it appears: at the start of a draw, part way through, or only when two fixtures run at once.
- Check the model name on the unit’s label so the technician can confirm the right parts.
For other brands, see our water heater guides.
Frequently Asked Questions About Noritz Error Codes
What does error code 11 mean on a Noritz tankless water heater?
Noritz describes code 11 as an ignition failure: the unit is not firing up to heat the water. It involves the gas supply and ignition system, so it needs a technician.
What does Noritz error code 90 mean?
Noritz describes code 90 as a combustion abnormality caused by an improper mixture of air and fuel. It points at the combustion air and gas supply, which is technician work on a gas appliance.
What does code 29 mean on a Noritz unit?
Noritz describes code 29 as a problem with condensate drainage. The drain route, its trap and the discharge point are all checked, because a blockage anywhere along that path produces the same code.
Can I reset a Noritz error code myself?
Noritz describes a power reset only as the first step for code 73, and advises contacting a licensed contractor if that code persists. The other common codes involve gas, combustion, drainage or temperature safety, and resetting them does not address the cause.
What is code F76 on a Noritz water heater?
Noritz describes F76 as a breakdown in communication between two tankless water heaters using the Quick Connect Cord. It only appears where two units are linked.
Get a Noritz Code Diagnosed
Read the code off the unit before you call. It tells us which subsystem to look at first and often which part comes on the truck.
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