EC91 or Error Code 91
An error code 91 means incorrect gas type.
For new installs:
- Verify the unit is provided the correct gas type.
- Verify the unit is installed according to the guidelines found in the installation manual either included with the unit or downloaded from our support site here: http://support.noritz.com/technical-literature
For existing installations:
- Verify the unit is provided the correct gas type.
- Verify the unit is installed according to the guidelines found in the installation manual either included with the unit or downloaded from our support site here: http://support.noritz.com/technical-literature
- Verify that the manifold gas pressures are correctly set. This should be done by a service rep according to the service manual for the unit.
- Perform a cleaning of the fan, burner and heat exchanger fins if there is dust, dirt, lint or other debris building up.
For further technical assistance call 866-766-7489 or use our Contractor Locator to find a local service representative.