Bosch ZBR 21-3 A NG User Manual

6721822579 (2021/01) US/CA
Installation and Service Instructions for Contractors
Residential Gas Condensing Boiler
Greenstar
0010004900-002
WARNING:
Improper installation, set-up, modification, operation or maintenance
of the heating system can cause personal injury and property damage.
Follow these instructions precisely.
If you require assistance or further information, contact a trained and
certified installer or the gas supply company.
WARNING:
The operating instructions are part of the technical documents that
must be handed over to the owner or operator of the heating system.
Explain to the owner or operator how to use the heating system using
the operating instructions. Make sure that they are familiar with all
required information for the safe and proper operation of the heating
system.
These instructions are available in English and French.
Please keep these instructions for future reference.
ZBR 21-3 A... | ZBR 28-3 A... | ZBR 35-3 A... | ZBR 42-3 A... | ZWB 28-3 A... | ZWB 35-3 A... |
ZWB 42-3 A...

Bosch ZBR 21-3 A NG Specifications

General

Brand	Bosch
Model	ZBR 21-3 A NG
Category	Boiler
Language	English

Summary

Explanation of Symbols and Safety Instructions

General Safety Instructions

Provides safety advice for gas leaks, flue gas, and general appliance handling.

Product Description

Product Dimensions and Minimum Clearances

Electrical Wiring ZBR...-3A

Regulations

Compliance with Standards and Regulations

Notes on Installation and Operation

Notes on Installation and Operation

Mounting the Appliance

Installing the Low Water Cut Off (LWCO)

Explains the procedure for installing the low water cut off device.

Connecting Flue Gas Accessories

Electrical Connection

General Notes

Outlines general electrical safety precautions and code requirements for installation.

Low Voltage Electrical Connections in the Heatronic Boiler Control

Electrical Connections in the Junction Box (120 VAC)

Connecting the LWCO Device

Guides the wiring process for the Low Water Cut Off (LWCO) device.

Commissioning

Before Operating the Appliance

Lists essential steps before the initial startup and operation of the appliance.

Switch on Heat

Details how to set the maximum supply temperature based on heating requirements.

ZBR...-3A Appliances (Heating Boilers) with DHW Tank: Setting the DHW Temperature

Setting Frost Protection

Explains how to set frost protection for the heating system and DHW tank.

Heatronic Boiler Control Settings

Guideline to Service Functions

Guides users on accessing and adjusting appliance settings via the Heatronic control.

Overview of the Service Functions

Description of the Service Functions

Gas Adjustment

Converting to a Different Gas Type

Details the procedure and precautions for converting the appliance to a different gas type.

Checking and Setting the Gas-Air Ratio (CO2 or O2), If Required

Guides on checking and adjusting the gas-air ratio for optimal combustion.

Flue Gas Test

Emissions Test Button

Describes how to use the emissions test button to select appliance outputs for testing.

Measuring CO Content of Flue Gas

Details the procedure for measuring CO content in flue gas and safety precautions.

Inspection and Maintenance

Description of Various Steps

Burner Servicing

Heat Exchanger Block Inspection and Cleaning

Setting the Boiler Water Pressure

Maintenance and Inspection Checklist

Provides a checklist to guide users through service and maintenance procedures.

Readings on the Display

Faults

Troubleshooting

Faults That Are Shown on the Display

Lists fault codes displayed on the unit and their corresponding eliminations.

Check Sensor Values

Commissioning Log for the Appliance