Navien NHB-055, Service Manual

Page: 116 / 147

116 NHB Service Manual Version 1.0
5.2.19 352Error
Error conditions and Check Items
Error Description
E352
High water pressure
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.
Check items
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
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
E352 High water pressure
Check the pressure increase conditions. (high water pressure of 56.6 psi or higher)
Check if the safety valve is stuck.
High water pressure
sensor
Defective water pressure
sensor
1. Check the output voltage. (Normal state : 0.3~2.8V)
However, at the time malfunction occurs at water pressure sensor Open or Short, low voltage error is not judged.