Navien NHB-055 Service Manual

76 NHB Service Manual
Version 1.0
4.9.12 Water Pressure Sensor
Part Check Point
Function Detects water pressure in the heating system.
Failure Event Unable to detect or measure to change in water pressure.
Effects Water filling system does not operate automatically
Error Code E302, E352, E353
Diagnostic
1. Visual inspection: check the circulation pump connection wire.
2. Voltage check: Check range of voltage shown below.
Testing/inspection
information
Black-Red : DC 0~5V
Legend to cross-section drawing
1. Pressure connection
2. Ceramic sensor
3. Amplifier electronics
4. Cover
5. Electrical connection (RAST 2.5)

Navien NHB-055 Specifications

General

Brand	Navien
Model	NHB-055
Category	Boiler
Language	English

Summary

Safety Information

Safety Definitions

Defines key safety terms used throughout the manual.

Safety Symbols

Explains the meaning of hazard symbols like Danger, Warning, Caution.

Safety Precautions

Lists essential safety measures to prevent hazards.

Product Information

Components

Identifies the main components of the boiler with a diagram.

Technical Data

General Specifications

Provides key operational and physical specifications for the models.

System Details

Setting the DIP Switches

Measuring the Inlet Gas Pressure

Details the procedure and importance of checking gas pressure.

Gas Conversion

Provides instructions for converting the boiler from natural gas to propane.

The Front Panel

Electrical Diagnostic Point & Wiring Diagram

Key Components Description

Troubleshooting

Error code classification

Lists error codes, their levels, functions, and recommended actions.

Troubleshooting guide by symptom

Offers solutions for common operational issues based on observed symptoms.

Replacement of Parts

Replacement Procedure

Components Replacement Instructions

Components Diagram and Part List

Heat Exchanger and Waterway Assembly

Combustion Parts Assembly

Inspection and Maintenance Schedule

Annual Servicing