Navien NHB-055, Service Manual

Page: 117 / 147

NHB Service Manual 117 Version 1.0
5.2.20 353Error
Error conditions and Check Items
Error Description
E353
Abnormal water pressure sensor
If an error (under 0.3V or over 2.8V) in the water pressure sensor is detected continuously for
3 seconds, The system displays the error message E353 on the front panel. If this occurs, the
boiler initiates shutdown.
Check items
1. Check if the cold water pipe input water pressure sensor is wet due to any reason, including
leakage.
2. Replace the water pressure sensor
3. Check the controller
Leaking in unit
Is the water pressure sensor
normal?
1. Check connecter
(#1,#2 and #3 of CN 22)
Check leaking in unit
Replace the water pressure sensor
Yes
No
Yes
No
Check method
Fault Possible Causes Check method
Abnormal water pressure
sensor
Defective water pressure
sensor
1. Check the sensor is frozen during the winter.
2. Check the output voltage. (Normal state : 0.3~2.8V)
3. Replace the PCB if power is not supplied.