Bosch 520-HN-N User Manual

520 HN
Flow Modulated with Hydro-generated Ignition
Suitable for heating potable water only - Not approved for space heating purposes
(Intended for variable flow applications with steady cold water inlet temperatures)
520-HN-N
520-HN-L
6 720 644 942 (2010/09) US
Warning: If the information in this manual is not
followed exactly, a fire or explosion may result
causing property damage, personal injury or death.
Do not store or use gasoline or other flammable
vapor and liquids in the vicinity of this or any other
appliance.
Improper installation, adjustment, alteration,
service or maintenance can cause injury or
property damage. Refer to this manual. For
assistance or additional information consult a
qualified installer, service agency or the gas
supplier.
In the Commonwealth of Massachusetts this
product must be installed by a licensed plumber or
gas fitter.
Upon completion of the installation, these
instructions should be handed to the user of the
appliance for future reference.
What to do if you smell gas
• Close gas valve. Open windows.
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any
phone in your building.
• Immediately call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire
department.
• Installation and service must be performed by a
qualified installer, service agency or the gas supplier.

Bosch 520-HN-N Specifications

General

Brand	Bosch
Model	520-HN-N
Category	Water Heater
Language	English

Summary

Warning and Safety Information

General Safety Warnings

Critical safety precautions and warnings for operating the appliance.

DANGER: High Temperature Water

Warning about the risk of severe burns or death from hot water.

Appliance Details

Technical Specifications

Installation Instructions

Venting Requirements

Detailed requirements for venting the appliance to ensure safe exhaust gas removal.

Combustion Air Requirements

Specifications for ensuring adequate combustion air supply for safe operation.

Mounting the Heater

Gas Piping and Connections

Procedures for connecting the gas supply line to the appliance safely.

Measuring Gas Pressure

Water Connections

Instructions for making plumbing connections, including the PRV.

Operation Instructions

Safety Before Operation

Essential safety checks and procedures before operating the water heater.

Lighting and Ignition

Step-by-step guide for lighting the pilot and igniting the main burners.

Adjusting Water Temperature

How to use control knobs to set and adjust the desired water temperature.

Power Adjustment

Using the power adjustment knob to regulate gas supply for temperature control.

Maintenance and Service

Water Valve Service

Troubleshooting

No Spark at Pilot

Steps to diagnose and resolve issues where the pilot fails to spark.

Spark Present, No Ignition

Troubleshooting when spark is present but pilot/burners do not ignite.

Pilot Lights, Burners Do Not Ignite

Diagnosing why burners fail to ignite after the pilot is lit.

Main Burners Go Out During Use

Temperature Fluctuations

Water Too Hot

Water Not Hot Enough

Low Hot Water Pressure

Burners Burn Uncleanly