Error - Navien NCB-24LSWE Service Manual

5.2.13 Error 218

Error conditions and checklist
Error
E218
Open heat
If an open (-10°C or lower) heat exchanger input temperature sensor is detected, the system displays
exchanger input
'218E' on the front panel. If this occurs, the boiler initiates shutdown.
temperature
sensor
1. Check if the heat exchanger input temperature sensor connector is wet due to any reason, including
Checklist
2. Replace the defective heat exchanger input temperature sensor.
3. Replace the controller.
106 NCB Service Manual
leakage.
Description
Version 1.0