Bosch ZBR 35-3 A NG User Manual

Commissioning
53
Greenstar – 6721822579 (2021/01)
8.7 ZWB...-3A appliances (combi boilers):
Setting the DHW temperature
▶ Set the DHW temperature on the DHW thermostat .
The set DHW temperature flashes on the display for 30 seconds.
Fig. 67 Set the DHW temperature (ZWB...-3A)
Table 25 Typical DHW temperatures for ZWB...-3A appliances
ECO button
Pressing and holding the ECO button until it lights up switches between
Comfort mode and Economy mode.
• Comfort mode (default setting)
The appliance is continually maintained at the set temperature.
Consequently, DHW draws are immediate, however the appliance
may run even if no DHW is being drawn.
• Economy mode, ECO button lights up
– DHW is only generated when DHW is drawn.
– On demand: Quickly open and close a DHW tap to signal the
appliance to heat to the selected temperature. After a short wait
DHW will be available.
The DHW on demand signal allows maximum gas and water savings.
8.8 Setting manual summer mode
In summer mode or warm weather shut down (WWSD), the heating zone
pump and consequently central heating are switched off. DHW
generation remains active following the DHW program.
See also the warm weather shutdown (WWSD) feature in the operating
instructions for the heating control included in the scope of delivery.
NOTICE
Heating system at risk of freezing.
In manual summer mode, only the appliance is protected from freezing.
▶ Observe frost protection measures where there is a risk of frost (
chapter 8.9).
▶ Note the supply temperature controller setting .
▶ Turn the boiler high limit dial counterclockwise as far as it will go:
.
Fig. 68 Summer mode
For further information, see the operating instructions for the heating
control included in the scope of delivery.
8.9 Setting frost protection
Frost protection of the heating system:
▶ Leave the appliance switched ON; set the boiler high limit to at least
95 °F (35 °C) (position 1,  Tab. 22, page 51).
Fig. 69 Frost protection of the heating system
-or-
▶ If you want to leave the appliance switched OFF: Mix Bosch-approved
anti-freeze into the heating water ( Tab. 29, page) and drain the
DHW circuit.
For further information, see the operating instructions for the heating
control included in the scope of delivery.
Frost protection of the DHW tank:
▶ Leave the appliance switched ON; set the boiler high limit to at least
95 °F (35 °C) (position 1,  Tab. 22, page 51).
▶ Turn the DHW thermostat counterclockwise as far as it will go
(50 °F (10 °C)).
Fig. 70 Frost protection for the DHW tank
DHW thermostat Typical DHW temperatures
min approx. 104 °F (40 °C)
e approx. 122 °F (50 °C)
max approx. 140 °F (60 °C)
6 720 641 933-55.1O
max
1
2
34
5
6
reset
eco
max
1
2
3
4
e
6
eco
reset
max
1
2
3
5
6
max
1
2
3
4
e
6
min
eco
reset
max
1
2
3
5
6
max
1
2
3
4
e
6
6 720 641 933-68.1O
min
max
1
2
3
e
6
max
1
2
34
5
6
eco
reset
6 720 615 065-15.1O
min

Bosch ZBR 35-3 A NG Specifications

General

Type	Condensing Boiler
Nominal heat output	35 kW
Fuel Type	Natural Gas
Water Pressure	1.0 - 3.0 bar
Weight	Approx. 45 kg

Summary

Explanation of Symbols and Safety Instructions

General Safety Instructions

Provides critical safety procedures for gas leaks, flue gas, and general appliance operation.

Product Description

Product Dimensions and Minimum Clearances

Provides graphical and numerical data for physical dimensions and required clearances.

Electrical Wiring ZBR...-3A

Electrical Wiring ZWB...-3A

Regulations

Compliance with Standards and Regulations

Details compliance with national, local codes, and specific standards like ANSI Z21.13/CSA4.9.

Operating Limits of the Boiler

Notes on Installation and Operation

Notes on Installation and Operation

Mounting the Appliance

Installing the Low Water Cut Off (LWCO)

Connecting Flue Gas Accessories

Explains how to attach vent flanges, flue gas adapters, and options for venting systems.

Installation of the Exhaust and Air Intake System

Details requirements for exhaust/air intake installation, including safety notices and direct vent systems.

Vent and Combustion Air Pipe Lengths

Electrical Connection

General Notes

Covers electrical safety, grounding, circuit breakers, and wiring requirements.

Electrical Connections in the Junction Box (120 VAC)

Connecting the LWCO Device

Commissioning

Before Operating the Appliance

Lists essential steps before powering on, including water filling, purging, and gas verification.

Switch on Heat

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

Explains how to set the domestic hot water temperature for ZBR...-3A models.

ZWB...-3A Appliances (Combi Boilers): Setting the DHW Temperature

Explains how to set the domestic hot water temperature for ZWB...-3A models.

Setting Frost Protection

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

ZBR...-3A Appliances (Heating Boiler) with DHW Tank: Thermal Disinfection

Heatronic Boiler Control Settings

Guideline to Service Functions

Overview of the Service Functions

Description of the Service Functions

Gas Adjustment

Converting to a Different Gas Type

Instructions and warnings for converting the appliance between natural gas and LPG.

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

Details the procedure for checking and adjusting the gas-air mixture using flue gas analysis.

Dynamic Gas Pressure Test Port

Flue Gas Test

Measuring CO Content of Flue Gas

Guides the measurement of CO levels in flue gas and safety limits.

Inspection and Maintenance

Description of Various Steps

Lists and briefly describes multiple maintenance procedures for the boiler.

Burner Servicing

Details the procedure for servicing the burner, including cover removal and cleaning.

Heat Exchanger Block Inspection and Cleaning

Provides steps for inspecting and cleaning the heat exchanger block using specific tools.

Maintenance and Inspection Checklist

A checklist to guide technicians through the service and maintenance procedure.

Faults

Troubleshooting

Provides general advice on troubleshooting, safety, and handling faults.

Faults That Are Shown on the Display

A table listing fault codes displayed on the unit and their corresponding elimination procedures.

Faults That Are Not Shown on the Display

Lists common faults that do not trigger a display code and their remedies.

Check Sensor Values

Provides resistance tables for various sensors to check their functionality.