Bosch KWB42-3 User Manual

Installation and Service Instructions for Contractors
Residential Gas Condensing Boiler
Greenstar FS/Combi FS
6720810590-00.2Wo
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.
NOTICE:
In Massachusetts, this appliance must be installed by a licensed
plumber or gas fitter.
These instructions are available in English and French.
Please keep these instructions for future reference.
Warranty information available at www.bosch-climate.us
Annual service is required
KBR16-3. |KBR21-3. |KBR28-3. |KBR35-3. |KBR42-3. |KWB28-3. |KWB35-3. |KWB42-3.
6720810590 (2015/05) CA/US

Bosch KWB42-3 Specifications

General

Brand	Bosch
Model	KWB42-3
Category	Boiler
Language	English

Summary

Key to Symbols and Safety Instructions

General Safety Instructions

Important safety precautions for gas, electrical, and fire risks.

Installation

Installation and Operation

Covers general guidelines for installing and operating the heating system.

Locating the Appliance

Installing a Low Water Cut Off (LWCO)

Guides the installation of a low water cut off device for boiler safety.

Connecting Flue Gas Accessories

Installation of the Exhaust and Air Intake System

Details the requirements for installing the exhaust and air intake system for safe operation.

Vent and Combustion Air Pipe Lengths

Testing Gas and Water Connections for Leaks

Outlines procedures for testing gas and water connections to ensure leak-free operation.

Making the Electrical Connections

General Notes

Provides essential safety and regulatory notes for electrical connections.

Electrical Connections in the Junction Boxes

Details how to access and make electrical connections via installer junction boxes.

Connecting an External Heating Zone Pump or DHW Recirculation Pump

Connecting Mains Power Supply

Guides the connection of the main power supply to the appliance.

Low Voltage (LV) Junction Box

Connecting the LWCO Device

Provides instructions for connecting the Low Water Cut Off device.

Commissioning

Before Operating the Appliance

Covers essential checks and preparations before initial operation of the boiler.

Startup

Setting Up Space Heating

Programming the FW 200 Heating Control Unit (Optional Accessory)

Setting Frost Protection

Instructions for setting frost protection for the heating system and DHW tank.

Gas Type Conversion

Converting to a Different Gas Type

Step-by-step guide for converting the appliance between gas types.

Setting the Gas-Air Ratio (CO2 or O2)

Instructions for adjusting the gas-air ratio for optimal combustion.

Inspection and Maintenance

Description of Various Steps

Checklist for Annual Inspection and Maintenance

Faults

Troubleshooting

General advice and safety precautions for troubleshooting appliance faults.

Faults That Are Shown on the Display

Lists display codes for faults and their corresponding elimination procedures.

Check Sensor Values