Equipment guide
Water Heater error codes
Codes are manufacturer-specific. Choose the exact brand shown on your equipment.
Official A.O. Smith material describes 1 flash as Low flame signal; the control continues to operate. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official A.O. Smith material describes 2 flash as Pressure switch failed closed. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official A.O. Smith material describes 3 flash as Pressure switch failed open. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official A.O. Smith material describes 4 flash as ECO (Energy Cut Off) limit thermostat temperature limit was exceeded; the main burner is shut off. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official A.O. Smith material describes 5 flash as Flame out of sequence sensed. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official A.O. Smith material describes 6-1 flash as Retry limit exceeded (failed trial for ignition). This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official A.O. Smith material describes 6-2 flash as Recycle limit exceeded: pressure switch/high limit opened. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official A.O. Smith material describes 6-3 flash as Recycle limit exceeded: flame lost. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official A.O. Smith material describes 6-4 flash as Recycle limit exceeded: flame out of sequence. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official A.O. Smith material describes 7 flash as Flammable Vapor Sensor (FVS) lockout. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official A.O. Smith material describes 8-1 flash as Flammable Vapor Sensor fault detected. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official A.O. Smith material describes 8-2 flash as Temperature sensor fault detected. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official A.O. Smith material describes 8-3 flash as Electronics fault detected. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official A.O. Smith material describes 8-4 flash as Valve fault detected. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E003 as Ignition failure. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E004 as False flame detection. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E012 as Flame loss. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E016 as Overheating of the heat exchanger. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E030 as Exhaust overheating - the water heater shuts down when the flue temperature exceeds 149 degrees F (65 degrees C). This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E046 as Abnormal operation: limit control. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E047 as Abnormal operation: exhaust thermostat. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E060 as Abnormal operation: dual venturi. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E109 as Abnormal operation: fan motor. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E110 as Abnormal air pressure. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E407 as Hot water outlet: thermistor open or short circuit. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E421 as Cold water inlet 1: thermistor open or short circuit. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E432 as Cold water inlet 2: thermistor open or short circuit. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E434 as Abnormal operation: water adjustment valve. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E438 as Abnormal operation: circulation pump. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E439 as Abnormal operation: flow sensor. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E441 as Hot water inlet 2: thermistor open or short circuit. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E445 as Abnormal operation: bypass mixing valve. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E515 as Abnormal operation: PCB (printed circuit board). This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E517 as Abnormal operation: DIP switch setting. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E593 as Abnormal operation: front panel key. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E615 as Abnormal operation: input and memory. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E736 as Abnormal operation: cascade communication. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E740 as Abnormal operation: outdoor temperature sensor. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E760 as Flushing/service alarm. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E782 as Abnormal operation: main panel communication. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Navien material describes E785 as Abnormal operation: flow switch/sensor. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Rheem material describes 11 as The gas shut-off valve is not fully opened, or gas service has been interrupted. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Rheem material describes 12 as LP gas is running low (LP models only). This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Rheem material describes 14 as Water heater is overheating. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Rheem material describes 1L as Water heater has buildup of lime deposits. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Rheem material describes 29 as Neutralizer is clogged. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Rheem material describes 31 as Faulty inlet thermistor. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Rheem material describes 33 as Faulty outlet thermistor. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Rheem material describes 61 as Faulty blower motor. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Rheem material describes 66 as Faulty bypass motor. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Rheem material describes 71 as Solenoid valve circuit failure. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Rheem material describes 88 as Reminder of flushing the heat exchanger and/or replacing the water treatment filter. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Rheem material describes 90 as Air intake or vent exhaust opening may be blocked; or the vent pipes on the vent termination may not be connected properly. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.
Official Rheem material describes P1 as Not enough water flow to operate the unit. This guide records the cited product-family scope, safety-reviewed owner checks, and service limits.