EC90 or Error Code 90
A 90 error code indicates a combustion abnormality. This means that the mixture of fuel and air is off from specification and is resulting in poor quality combustion.
Common issues associated with a 90 error code:
1) Insufficient gas supply
2) Blockage in the flue vent
3) Debris in the fan motor
It is recommended you contact a servicer to troubleshoot this error.
Please visit http://support.noritz.com/servicereplocator.php to find a local service representative.
- Models: ALL MODELS
The following video outlines some basic maintenance for a Noritz Tankless Water Heater, which may help resolve 90 error codes: