Water Pressure Sensor - Navien NCB300-28K Service Manual

4.7.15 Water Pressure Sensor

Item
Function Analysis of heating system water pressure ratios.
Fault Unable to detect or measure changes of water pressure.
Symptoms The water top-up system does not operate automatically.
Error codes E351, E352, E353
1. Visual inspection: Check the circulation pump's wiring connections.
Diagnostics
2. Voltage test: Test the voltage meets the specifications shown below.
Testing/inspection
Black-Red: DC 0-5 V
information
Description
System Details 51