Noritz NRC Series error codes
Noritz gives this generation one diagnostic table and two ways of showing you the fault, and that catches people out. There is a display window on the circuit board inside the cabinet, visible through a small opening, which shows a three-digit code — and there is the remote controller in the house, which shows two digits for the same fault. A 321 in the window and a 32 on the controller are one problem, not two. Every page below is filed under the remote controller number, with the display-window numbers listed so a search for either lands here. Noritz prints this table in two service manuals: the 2013 manual covering NR501-OD, NR662-OD, NRC661 and NRC711, and the 2017 EZTR manual covering the NRC663-FSV (EZTR40). The two were compared row by row and they differ in exactly one place — code 94, where the 2017 document labels the two sub-codes and the earlier one does not. Do not read this table for an EZ98DV, EZ111DV or NCC199CDV: those share a cabinet with the NRC663 but have their own, different table.
Not your models? Check the model-number decoder before you read the table below — the code numbers repeat across series and the meanings do not.
| Code | Error | Verdict |
|---|---|---|
| 11 | Ignition failure | Call a pro |
| 12 | Flame rod does not detect flame | Call a pro |
| 14 | Thermal fuse triggered | Call a pro |
| 16 | Abnormally high output temperature | Call a pro |
| 20 | High limit switch triggered | Call a pro |
| 29 | Condensate container clogged | DIY fix |
| 30 | Air thermistor fault | Part replacement |
| 31 | Cold water thermistor fault | Part replacement |
| 32 | Hot water thermistor fault | Part replacement |
| 33 | Heat exchanger thermistor fault | Part replacement |
| 35 | Exhaust thermistor fault | Call a pro |
| 51 | Gas solenoid valve failure | Call a pro |
| 61 | Fan motor fault | Call a pro |
| 70 | Circuit board fault | Part replacement |
| 71 | Gas solenoid valve drive circuit fault | Call a pro |
| 72 | Flame rod circuit fault | Call a pro |
| 73 | Circuit board setting fault | Call a pro |
| 76 | Display window communication fault | Part replacement |
| 90 | Air flow or combustion fault | Call a pro |
| 91 | Improper gas type | Call a pro |
| 94 | Exhaust temperature too high | Call a pro |
| 99 | Combustion fault, unit locked | Call a pro |
| 760 | Remote controller communication fault | Part replacement |
| C1 | Scale build-up in the heat exchanger | DIY fix |
| CF | Scale lockout | Call a pro |
Every entry above is transcribed from the manufacturer's diagnostic documentation for this exact series, with the source cited on each code page.
Other Noritz series
Different series, different code table — if your unit isn't a NRC Series, check yours: