Error Code List And Actions - Navien NCB500-2S/37K Service Manual

5.2 Error Code List and Actions

Error Code Sub Code
E001 0 Overheating of heat exchanger
E003 0 Ignition failure
E004 0 False flame detection
E012 0 Flame loss
E016 0 Heat exchanger overheat
E030 0 Abnormal exhaust temperature.
E031 2 Overheating of burner
Abnormal operation: Heat
E046 2
exchanger overheating sensor
1 Exhaust thermistor open error
E047
2 Exhaust thermistor short error
E109 0 Fan motor activity error
Function
1. Clean the strainer.
2. Check voltage via PCB at the pump.
3. (AC 230 V)
4. Check that the flow rate is correct.
5. Check if water is circulating in the heating lines.
6. Check the heat exchanger and flush it with cleaning solution if
1. Check the main gas supply
2. Check if the manual gas valve is open.
3. Check if the igniter is sparking.
4. Tighten the ground terminals on the heat exchanger.
1. Ensure that the ground wire is connected.
2. Check if the igniter is sparking.
1. Check if the main gas valve is open and verify the incoming gas
2. Check the gas valve inlet filter.
3. Check the ground wire.
4. Check the power supply.
5. Tighten the ground terminals on the heat exchanger.
6. Adjust the anti-short cycle time.
1. Turn OFF the boiler, wait at least 30 min, and then restart the boiler.
2. Clean the inlet water filter and strainer.
3. Check the high limit switch and PCB.
4. Check the 3-way valve.
5. Check the heat exchanger and flush it if required.
1. Turn OFF the boiler, wait at least 30 min, and then restart the boiler.
2. Clean the strainer.
3. Check the heat exchanger and flush it if required.
1. Turn off the boiler.
2. Check if all the valves on the distribution manifold are closed.
3. Check if the burner overheat prevention is disconnected.
Check the heat exchanger thermistor connection.
Check the exhaust thermistor connection.
1. Check and clean the air intake filter.
2. Check and clean the fan motor.
3. Test the voltage from the PCB to ensure that it is correct. Replace
Diagnosis/Actions
necessary.
pressure.
fan if PCB voltage is normal.
Troubleshooting 57