Navien NHB-055 Service Manual

NHB Service Manual 125
Version 1.0
5.3.3 Circuit breaker operation
Error type Cause Check method
Circuit breaker trips
Power supply
The circuit breaker trips immediately as soon as the power cord is plugged in the
receptacle.
Check the sheath of power cord, or if there is short-circuit.
Check the components in order from the power transformer to the PCB.
Defective part assembly
If the circuit breaker operates after repairs check the wiring of each part.
Maintain proper direction when assembling the ignition transformer.
Be careful that wire is not compressed when assembling the main gas valve
Check if the wire is fixed and properly attached on the main side of the heat
exchanger.
Normal assembly
Short-circuit due to defective assembly Wiring near the heat exchanger
Circuit breaker operates
while the boiler is
running
If circuit breaker trips during the operation of the boiler, check the order of
operation, and replace the concerned part.
e.g., The circuit breaker operates at switchover to burner stage 2 after ignition.
►
Replace the dual venturi.
Remote controller power Check the wire
Check the power supply to the remote controller terminal. (DC 19 V or higher).
If there is a problem in power supply, check the output voltage of the PCB, and take
the action separately for wiring error and defective PCB, respectively.
If the power supply is normal, replace the remote controller.

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