Your safety is our #1 priority. Contact Happy Plumbing for further troubleshooting. Our technicians can help you diagnose the problem.
Please note: Your water heater model may use different codes or may provide error codes that are not given here. Therefore you’ll want to consult the manual for your specific heater.
| ERROR CODE | REASON | Self-diagnostics/ Action | Reset |
|---|---|---|---|
| Navien Error Code E001 | Water is boiling inside the heat exchanger | Clean the inlet water filter Check the heat exchanger; flush it with a cleaning solution | Manual |
| Navien Error Code E002 | Low water pressure | Wait until the water supplement is terminated. | Automatic |
| Navien Error Code E003 | Ignition failure | Check if the main gas supply valve is open Check the igniter for spark | Manual |
| Navien Error Code E004 | False flame detection | Check if the main gas supply valve is open Check the igniter for spark | Automatic |
| Navien Error Code E005 | Heating supply outlet: Thermistor–open | Ensure the ground wire is connected Check the igniter for spark | Automatic |
| Navien Error Code E006 | Heating supply outlet: Thermistor–short | Check the thermistor Check for loose connection Replace the thermistor | Automatic |
| Navien Error Code E007 | Hot water outlet: Thermistor–open | Check the thermistor Check for loose connection Replace the thermistor | Automatic |
| Navien Error Code E008 | Hot water outlet: Thermistor–short | Check the thermistor Look for short or water in connection Replace the thermistor | Automatic |
| Navien Error Code E09 | Abnormal fan motor activity | Check and clean the air filter Check and clean the fan motor Check the tower on board for loose connection | Manual |
| Navien Error Code E010 | Abnormal air pressure | Check the vent and fresh air pipe for obstructions Check and clean the air filter Check hoses and condensate drain | Manual |
| Navien Error Code E011 | High water pressure | Check the water pressure sensor | Automatic |
| Navien Error Code E012 | Flame loss | Check the main gas line (valve open?) Check the intake air pipe Check ground wire Check power supply Clean flame rod | Manual |
| Navien Error Code E013 | Abnormal pump | Check the pump Remove air from the pipe | Manual |
| Navien Error Code E015 | Abnormal control board | Check power supply Check the Emergency Switch | Manual |
| Navien Error Code E016 | Overheating of heat exchanger | Turn OFF the system for at least 30 minutes then restart Clean the inlet water filter Check the heat exchanger; flush with a cleaning solution | Manual |
| Navien Error Code E018 | Heating return inlet: Thermistor–open | Check the Thermistor Check for loose connection Replace the Thermistor | Automatic |
| Navien Error Code E019 | Heating return inlet: Thermistor–short | Check the Thermistor Check for short or water in connection Replace the Thermistor | Automatic |
| Navien Error Code E021 | Cold water inlet: Thermistor–open | Check the Thermistor Check for loose connection Replace the Thermistor | Automatic |
| Navien Error Code E022 | Cold water inlet: Thermistor–short | Check the Thermistor Check for short or water in connection Replace the Thermistor | Automatic |
| Navien Error Code E027 | Abnormal activity of the air pressure sensor | Check the vent pipe for obstructions Check and clean the air filter | Automatic |
| Navien Error Code E028 | Water leak pipeline | Check pipeline. | Manual |
| Navien Error Code E030 | Exhaust Overheat: exhaust high limit the switch shuts down the unit when the flue temperature exceeds 149°F (65°C) | Clean the inlet water filter Check the heat exchanger; flush it with a cleaning solution | Automatic |
| Navien Error Code E035 | Abnormal activity of the gas pressure sensor | Measure gas pressure drop Check hose connection Replace GPS. | Manual |
| Navien Error Code E036 | Communication failure | Contact Navien tech. dept. | Automatic |
| Navien Error Code E039 | Abnormal the Water Flow Sensor | Check the water flow sensor. | Manual |
| Navien Error Code E040 | Outdoor: Thermistor–short | Check the Thermistor Replace the Thermistor | Manual |
| Navien Error Code E048 | Abnormal LPG Gas Pressure | Check the LPG Gas. Fill the LPG Gas. | Manual |