Error - Navien NCB-700-2S+/42K Service Manual

5.2.16 Error 352

Error conditions and checklist
Error
E352
High water pressure
Checklist
Testing method
Fault
E352
High water pressure
sensor
If an error signal is received from the water pressure sensor, the system displays the E352
on the front panel. High water pressure errors occur if the water pressure is 3.9 bar or
higher for 3 sec.
The error is automatically cancelled if the water pressure returns to 3.9 bar or lower.
1. Check if the input water pressure sensor is wet for any reason, including leakage.
2. Check the controller.
Is there a leak inside
the boiler?
No
Is the water
pressure sensor
normal?
Yes
1. Check connections
Possible causes
Check the water supply pressure. (3.9 bar or higher is the error state)
High water pressure Check if the safety valve is stuck.
Check the Auto feeder valve.
1. Check the output voltage. (Normal state: 0.25-4.93 V)
Water pressure sensor
fault
2. Replace the faulty or open water pressure sensor.
Description
Yes
Repair the leak
No
Replace the water pressure sensor
Check method
Troubleshooting 93