Navien NCB500-2S/37K User Manual

80 Troubleshooting
5.2.12 Error 218
Error conditions and checklist
Error Description
E218
Open heat exchanger input temperature
sensor
If an open (-10°C or lower) heat exchanger input temperature sensor is detected, the
system displays 218E on the front panel. If this occurs, the boiler initiates shutdown.
Checklist
1. Check if the heat exchanger input temperature sensor connector is wet due to any
reason, including leakage.
2. Replace the defective heat exchanger input temperature sensor.
3. Replace the controller.
Is the inlet thermistor
normal?
Check connections
Replace inlet thermistor
No
Yes
Before measuring thermistor
resistance, disconnect it from the
PCB.

Navien NCB500-2S/37K Specifications

General

Brand	Navien
Model	NCB500-2S/37K
Category	Boiler
Language	English