Navien · Water Heater error code
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Get lifetime accessOnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.
Guide · Water HeaterA.O. Smith and Rheem both call for testing the temperature-and-pressure relief valve at least once a year and flushing sediment at least yearly (every six months in hard water, and A.O. Smith's manual says every six months). Anode intervals vary by maker and water: check it annually to every few years and replace it when several inches of core wire show. Set the thermostat around 120 F. On gas units, look at the vent and burner area but leave any gas-side work to a licensed tech.
Guide · Water HeaterAn instant trip almost always means a dead short: an element shorted to the tank, a pinched or burnt wire, or water in the junction box. A trip after minutes or hours points to a weak/overheated breaker connection, loose terminals heating up, or a breaker sized too small for the heater. Test everything with power off and verified dead; never keep resetting a breaker that trips instantly.
Guide · Water HeaterKill and verify power, test the element (ohms and to-ground), drain the tank below the element (or fully), remove it with an element socket, and install a replacement that matches the original's voltage, wattage and mounting style (screw-in or bolt-on flange). Low watt density elements spread the same wattage over more surface; they scale more slowly and are quieter, and can replace a high-density element of the same voltage and wattage. Never exceed the wattage on the tank's rating plate. Refill completely and bleed air before restoring power: an element powered dry burns out in seconds.
Navien · Water Heater
E003
Ignition failure
Navien · Water Heater
E004
False flame detected
Navien · Water Heater
E012
Flame loss during operation
Navien · Water Heater
E016
Overheating
Navien · Water Heater
E030
Exhaust overheat
Navien · Water Heater
E046
Limit control abnormality