Noritz NRC661-DV, Service Manual, Page: 52 / 78

52
903 Combustion abnormality
Check gas type.
Unit Status
NG 110%
LP 110%
NG 104%
LP 104%
Model Name Gas type Unit operation
Maintenance Monitor #49
Final Fan Speed Correction
NRC711-OD
Unit shuts .
NRC711-DV
908 Combustion abnormality
(Unit is locked)
If 1 to 4 check out okay, replace the Fan Motor.
Replace the Circuit Board set if the error code is displayed again.
* It is not necessary to replace the Display Window Circuit Board.
* How to reset the lock is described in page 25.
<Condition of occurrence for error code 903>
When the unit is operating,
- Air inlet for blockage or obstruction.
- Exhaust for blockage or obstruction.
- Fan Motor is abnormal.
<Condition of occurrence for error code 908>
If the Unit detects “Error Code 901” 6 times,
the Unit is locked* for safety.
1 Check air inlet for blockage or obstruction.
2 Check exhaust for blockage or obstruction.
3 Check the Fan Motor.
(ex. Clogging of fan blades, etc.)
4 Check for sudden environmental changes.
(ex. Hurricane, Storm, etc.)
Improper gas type
Error Codes
Description
91 91
Display
Window
Remote
Controller
The trouble diagnosis for “Error Code 908” is same “Error Code 901”.
Basically, replace the Burner.
<Condition of occurrence for error code 94>
The Unit detects high exhaust temperature.
1 Check air inlet for blockage or obstruction.
2 Check exhaust for blockage or obstruction.
3 Check for Heat Exchanger-Primary is normal.
4 Check for inlet water temperature is high.
Exhaust temperature is too high DV model only
Error Codes
Description
94 941, 942
Display
Window
Remote
Controller