Error - Navien NCB500-2S/37K Service Manual

5.2.15 Error 353

Error conditions and checklist
Error
E353
Water pressure sensor fault
Checklist
Testing method
Fault
Water pressure sensor
fault
If a voltage error (< 0.3 V or > 5 V) at the water pressure sensor is detected continuously for
3 sec, the system displays E353. When this error occurs, the boiler shuts down.
1. Check if the input water pressure sensor is wet due to any reason, including leakage.
2. Replace the water pressure sensor.
3. Check the controller.
Is there a leak inside
the boiler?
No
Is the water
pressure sensor
normal?
Yes
1. Check connections
Possible causes
1. Check if the sensor is frozen.
Water pressure sensor
2. Check the output voltage. (Normal state: 0.25-4.93 V)
fault
3. Replace the PCB if the voltage is not correct.
Description
Yes
Repair the leak in the boiler
No
Replace the water pressure sensor
Testing method
Troubleshooting 83