352Error - Navien NHB-055 Service Manual

5.2.19 352Error

Error conditions and Check Items
Error
E352
High water pressure
Check items
Check method
Fault
E352
High water pressure
sensor
However, at the time malfunction occurs at water pressure sensor Open or Short, low voltage error is not judged.
116 NHB Service Manual
Upon receiving a signal from the water pressure sensor, the system displays the error(E352) on
front panel.
High water level error if the water level of 56.6 psi or higher continues 3 seconds.
Error is automatically cancelled if water level is 43.5 psi or lower.
1. Check if the cold water pipe input water pressure sensor is wet due to any reason, including
leakage.
2. Check the controller
Leaking in unit
No
Is the water pressure sensor
normal?
Yes
1. Check connecter
(#1,#2 and #3 of CN 22)
Possible Causes
Check the pressure increase conditions. (high water pressure of 56.6 psi or higher)
High water pressure
Check if the safety valve is stuck.
Defective water pressure
1. Check the output voltage. (Normal state : 0.3~2.8V)
sensor
Description
Yes
Check leaking in unit
No
Replace the water pressure sensor
Check method
Version 1.0