Navien NHB-055 Service Manual

NHB Service Manual 119
Version 1.0
5.2.22 517Error
Error occurrence conditions and check items
Are the DIP S / W on the PCB
properly set?
Change the DIP S / W to the
proper settings
* If problem persists, replace the PCB
Reset the unit
Yes
NO
5.2.23 594Error
Error occurrence conditions and check items
Error Description
E594 error If the communication is abnormal in parts of PCB, the system displays E594 on the PCB.
Check items Check the PCB.
Error occurrence conditions and check items
Fault Possible Causes Check method
E594 Error
Abnormal
communication by PCB.
1. Click the Reset button on Front panel.
2. Turn the POWER to the unit OFF then ON. Disconnect then reconnect power if
necessary.
3. If the system still displays E594, replace the main PCB.

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