Noritz Combustion Control / Feedback Fault

Error code 93 appears; unit may shut down or fail to start.

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Abnormal combustion detected by control logic, Incorrect gas pressure, Blocked burner or heat exchanger, Faulty combustion sensor or PCB

Safety first: Turn OFF power and gas. Do not operate the unit until combustion issues are resolved.

Steps to check and correct:

Check venting and intake: Ensure both are clear and installed correctly.
Verify gas supply: Have a professional check gas type and pressure.
Clean burner and descale: Remove and clean burner; perform a descaling flush on the heat exchanger.
Professional service: Error 93 often requires a Noritz technician to evaluate combustion sensors and PCB and perform combustion analysis.

Professional Required 5/5

Main Control PCB

Check Price on Amazon

We may earn a commission from links on this page.