Bosch 520-PN-L Specifications


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Bosch 520-PN-L Specifications | Manualzz

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.

INDOOR MODEL Flow Modulated with Standing pilot

520 PN

520-PN-N / 520-PN-L

Suitable for heating potable water only - Not approved for space heating purposes

(Intended for variable flow applications with steady cold water inlet temperatures)

2 | Index

Index

1 Key to symbols and safety instructions . . . . . . . . . . . . 3

1.1 Key to symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2 Safety instructions . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Warning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3 Appliance details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.1 520 PN specifications (Technical data) . . . . . . . . 7

3.2 Unpacking the 520PN heater . . . . . . . . . . . . . . . . . 8

3.3 General rules to follow for safe operation . . . . . . . 8

3.4 Dimensions and installation clearances . . . . . . . . . 9

7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

7.2 Pilot does not light . . . . . . . . . . . . . . . . . . . . . . . . 25

7.3 Pilot lights, but goes out when button is released . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

7.4 Pilot goes out during or after hot water use . . . . . 26

7.5 Burners do not light with water flow . . . . . . . . . . 26

7.6 Hot water temperature fluctuates at tap . . . . . . . 26

7.7 Water is too hot . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

7.8 Water is not hot enough . . . . . . . . . . . . . . . . . . . . 27

7.9 Burners ignite without hot water flow . . . . . . . . . 27

7.10 Low hot water pressure . . . . . . . . . . . . . . . . . . . . 27

7.11 Noise when heater is running . . . . . . . . . . . . . . . . 28

7.12 Burners do not operate cleanly; yellow flames when operating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4 Installation instructions . . . . . . . . . . . . . . . . . . . . . . . . 10

4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.2 Proper location for installing your heater . . . . . . 10

4.3 Heater placement and clearances . . . . . . . . . . . . 11

4.4 Mounting Heater . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4.5 Combustion air requirements . . . . . . . . . . . . . . . . 12

4.6 Venting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4.6.1Horizontal venting . . . . . . . . . . . . . . . . . . . . . . . . . 13

4.6.2Vertical venting . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4.7 Gas piping & connections . . . . . . . . . . . . . . . . . . . 15

4.8 Measuring gas pressure . . . . . . . . . . . . . . . . . . . . 19

4.9 Water connections. . . . . . . . . . . . . . . . . . . . . . . . 19

4.10 Recirculation application . . . . . . . . . . . . . . . . . . . 20

8 Protecting the environment . . . . . . . . . . . . . . . . . . . . 28

9 Interior components and diagram parts list . . . . . . . 29

9.1 Interior components . . . . . . . . . . . . . . . . . . . . . . . 29

9.2 Components diagram . . . . . . . . . . . . . . . . . . . . . . 30

9.3 Parts list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

10 LIFETIME LIMITED WARRANTY FOR BOSCH TANKLESS

WATER HEATERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

11 Installer Checklist to be completed by installer upon installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

5 Operation instructions . . . . . . . . . . . . . . . . . . . . . . . . . 20

5.1 For your safety read before operating your water heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

5.2 Lighting instructions . . . . . . . . . . . . . . . . . . . . . . . 21

5.3 To turn off appliance . . . . . . . . . . . . . . . . . . . . . . . 22

5.4 Setting the water temperature . . . . . . . . . . . . . . . 22

5.5 Draining water from heater . . . . . . . . . . . . . . . . . . 23

6 Maintenance and service . . . . . . . . . . . . . . . . . . . . . . . 23

6.1 Maintenance intervals . . . . . . . . . . . . . . . . . . . . . . 23

6.2 Water valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

6.3 Pilot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6.4 Main burners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6.5 Vent assembly / heat exchanger . . . . . . . . . . . . . . 24

6.6 Mineral scale build-up . . . . . . . . . . . . . . . . . . . . . . 24

6.6.1Descaling heat exchanger . . . . . . . . . . . . . . . . . . . 24

7 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

6 720 644 947 (2014/11) 520 PN

1 Key to symbols and safety instructions

1.1

Key to symbols

Warnings

Warnings in this document are identified by a warning triangle printed against a grey background.

Keywords at the start of a warning indicate the type and seriousness of the ensuing risk if measures to prevent the risk are not taken.

The following keywords are defined and can be used in this document:

DANGER indicates a hazardous situation which, if not avoided, will result in death or serious injury.

WARNING indicates a hazardous situation which, if not avoided, could result in death or serious injury.

CAUTION indicates a hazardous situation which, if not avoided, could result in minor to moderate injury.

NOTICE is used to address practices not related to personal injury.

Important information

This symbol indicates important information where there is no risk to people or property.

Additional symbols

Symbol Explanation

Step in an action sequence

Cross-reference to another part of the document

List entry

List entry (second level)

Table 1

Key to symbols and safety instructions | 3

1.2

Safety instructions

Read all instructions before installing. Perform the steps in the indicated sequence. Have the water heater inspected by a trained service technician at least once every year. Failure to comply with these instructions can result in severe, possibly fatal, personal injury as well as damage to property and equipment.

Installation and servicing

▶ Risk of fire when soldering and brazing!

Take appropriate protective measures when soldering and brazing around combustible and flammable material.

▶ Ensure that only a licensed contractor installs or services the water heater.

▶ On hot components use only material with adequate temperature stability.

Installation and commissioning

▶ In the Commonwealth of Massachusetts, the water heater must be installed by a licensed plumber.

▶ Do not install this device in rooms with a high moisture level

(e.g. bathrooms, saunas).

Function

▶ To ensure that the water heater functions properly, follow these installation and maintenance instructions.

▶ Never close the blow-off line of the T&P safety valve. For safety reasons, water may escape during heating.

If you smell gas

▶ Turn off the gas shut-off valve.

▶ Open windows and doors.

▶ Do not try to light the appliance.

▶ Do not touch any electrical switch, telephone, and do not use outlets.

▶ Extinguish all open flames. Do not smoke! Do not use lighters!

▶ Warn all occupants of the building. Do not ring doorbells!

▶ If you can hear gas leaking, leave the building immediately.

▶ Prevent others from entering the building and notify the police and fire department from outside the building.

▶ From outside the building, call the gas utility company and a trained and certified installer.

If you smell flue gas

▶ Switch off the appliance.

▶ Open windows and doors.

▶ Inform a trained and certified installer.

520 PN 6 720 644 947 (2014/11)

4 | Key to symbols and safety instructions

Insufficient ventilation may cause toxic flue gas to escape.

Risk of poisoning.

▶ Never close off or reduce the size of the air intake and outlet openings.

▶ The appliance must not be operated until any obstructions have been removed.

▶ Inform the system operator in writing of the problem and the associated dangers.

Danger from escaping flue gases

▶ Ensure all vent pipes and chimneys are not damaged or blocked.

▶ Connect only one appliance to each vent system or chimney liner.

▶ The venting system piping must not feed into another air extraction duct.

▶ Do not route the flue system piping through or inside another air extraction duct.

Danger of explosion of flammable gases

▶ Work on gas components may only be carried out by a trained and certified installer.

▶ Installation, gas and flue connection, initial commissioning, electrical connections and annual maintenance must only be carried out by a trained and certified installer.

Combustion air

▶ Keep the combustion air free of corrosive substances

(halogenated hydrocarbons that contain chlorine or fluorine compounds).

Never shut off safety valves!

▶ Water may escape from the safety valve at any time when the water is being heated.

inspection/maintenance

▶ servicing and repairs may only be carried out by a trained and certified installer.

▶ immediately correct all faults to prevent system damage.

▶ use only bosch spare parts! damage caused by the use of parts not supplied by bosch may void the warranty.

instruct the customer

▶ explain to the customer how the appliance works and how to operate it.

▶ inform the customer that he/she must not carry out any alterations or repairs.

Danger from electric shock

▶ Ensure that only an authorized contractor performs electrical work.

▶ Before performing electrical work, disconnect the power and secure the unit against unintentional reconnection.

▶ Ensure the system has been disconnected from the power supply.

Risk of scalding at the hot water draw-off point

▶ When the water heater is in operation, temperatures in excess of 122 °F (50 °C) can occur. To limit the temperature at the tap, install a thermostatic DHW mixing valve.

▶ Water heated for washing the laundry, dishes and for other cleaning purposes can cause scalding and permanent injuries.

▶ Children, elderly, and handicapped persons are more likely to be permanently injured by hot water. Never leave such individuals in the tub or shower unattended under any circumstances. Children must not be allowed to operate hot water faucets themselves or to fill a bathtub.

▶ If the building has occupants in the above groups who operate hot water faucets, or state laws / local ordinances stipulate specific water temperatures, take the following precautions:

– Use the lowest possible temperature setting.

– To prevent scalding, install a tempering device, such as an automatic mixing valve, at hot water tap or water heater. Select and install the automatic mixing valve in accordance with the valve manufacturer's recommendations and instructions.

▶ Water exiting from drain valves can be extremely hot. To avoid injuries:

– Check that all connections are tight.

– Direct exiting water away from people.

▶ Measures must be taken to protect against excessive temperature and pressure! Installation of a T&P safety valve is required.

To protect against corrosion and ensure compliance with the rules for electrical safety, observe the following points:

▶ Use metal fittings for potable water heating systems with plastic piping.

▶ Use only original accessories from the manufacturer.

▶ When installation of the water heater is complete, inspect the ground conductor (including metal fittings).

6 720 644 947 (2014/11) 520 PN

Maintenance

Customers are advised to:

▶ Sign a maintenance and inspection contract with an authorized contractor. Inspect and maintain the water heater as necessary and on a yearly basis. Service as needed.

▶ Use only genuine spare parts.

Flooding

▶ After a flood, do not use the appliance if any part has been submerged. Damage to appliances that have been submerged can be quite severe and pose numerous safety risks.

▶ Every appliance that has been submerged must be replaced.

For your safety

▶ Do not store or use gasoline or other flammable, combustible or corrosive vapors and liquids in the vicinity of this or any other appliance.

DANGER: Fatal accidents!

Carbon monoxide poisoning.

▶ Carefully plan where you install the heater. Correct combustion air supply and flue pipe installation are very important. If a gas appliance is not installed correctly, fatal accidents can result such as carbon monoxide poisoning or fire.

DANGER:

Carbon monoxide poisoning.

▶ Exhaust gas must be vented to outside using approved vent material. See

table 5, page 15 (In Canada use only

ULCS636 approved material). Vent and combustion air connector piping must be sealed gas-tight to prevent flue gas spillage, carbon monoxide emissions and risk of fire, resulting in severe personal injury or death. Approved vent terminations must be used when penetrating to the outside.

520 PN

Key to symbols and safety instructions | 5

DANGER: Electric shock!

▶ Field wiring connections and electrical grounding must comply with local codes, or in the absence of local codes, with the latest edition of the National

Electric Code, ANSI/NFPA 70, or in

Canada, all electrical wiring must comply with the local codes and the

Canadian Electrical Code, CSA C22.1

Part 1.

DANGER: Electric shock!

Shock hazard: line voltage is present.

▶ Before servicing the water heater, unplug power supply cord from outlet.

Failure to do so could result in severe personal injury or death.

WARNING: Damage to the appliance from over pressure.

▶ The heater must be disconnected from the gas supply piping system during any pressure testing of that system at test pressures equal to or more than 0.5 psi.

NOTICE:

▶ The appliance should be located in an area where leakage of the heater or connections will not result in damage to the area adjacent to the appliance or to lower floors of the structure. When such locations cannot be avoided, it is recommended that a suitable drain pan, adequately drained, be installed under the appliance. The pan must not restrict combustion air flow.

WARNING:

▶ The maximum inlet gas pressure must not exceed the value specified by the manufacturer and the minimum value listed is for the purpose of input adjustment.

6 720 644 947 (2014/11)

6 | Warning

NOTICE:

▶ If a water heater is installed in a closed water supply system, such as one having a backflow preventer in the cold water supply line, means shall be provided to control thermal expansion.

Contact the water supplier or local plumbing inspector on how to control this situation.

WARNING: Fire danger!

▶ Keep appliance area clear and free from combustible materials, gasoline and other flammable vapors and liquids.

NOTICE:

▶ Do not obstruct the flow of combustion and ventilation air.

NOTICE: Appliance malfunction!

▶ If power is lost while appliance is operating. Turn off both water and power for 15 seconds to reset device.

WARNING: Risk of scalding and property damage.

▶ Precautions must be taken prior to manually operating the relief valve to avoid contact with hot water discharged from the relief valve and to prevent water damage.

NOTICE: Appliance damage!

▶ Label all wires prior to disconnection when servicing controls. Wiring errors can result in improper and dangerous operation. Verify proper operation after servicing.

WARNING: System damage!

▶ If a relief valve discharges periodically, this may be due to thermal expansion in a closed water supply system. Contact the water supplier or local plumbing inspector on how to correct this situation. Do not plug the relief valve.

WARNING: Property damage!

▶ If the water heater is used in a space heating application, all piping and components connected to the water heater must be suitable for use with potable water.

WARNING: Personal Injury from toxic chemicals.

▶ Toxic chemicals, such as those used for boiler treatment, shall not be introduced into the potable water used for space heating.

WARNING: Personal Injury from toxic chemicals.

▶ A water heater which will be used to supply potable water shall not be connected to any heating system or component(s) previously used with a nonpotable water heating appliance.

2 Warning

WARNING:

▶ The heater must be isolated from the gas supply piping system during any pressure testing of that system at test pressures equal to or more than 0.5 psig.

6 720 644 947 (2014/11) 520 PN

Fig. 1

3 Appliance details

3.1

520 PN specifications (Technical data)

Approved in US/Canada

Capacity

520 PN: 4.3 GPM

Accessories (Bosch part #)

• Pressure relief valve (FWL-2)

520 PN

CAUTION:

▶ Any changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment.

Appliance details | 7

• Freeze prevention kit (7709003775)

1)

Safety devices

• Flame failure device (ionization flame rod sensor)

• Pressure relief valve (Available as accessory)

• Over heat prevention (temperature limiter)

Capacity

Maximum output

Maximum input

Thermal efficiency

(Efficiency in %)

BTU/hr 91 525 Btu/hr

BTU/hr 117 000 Btu/hr

% > 78%

Minimum Input BTU/hr 30 735 Btu/hr

Gas Requirement

Gas connection inches

Inlet gas pressure under maximum operation 1)

½ ” NPT

Propane

Natural Gas water column water column

10.5” - 14”

5.7” - 14”

Water

Hot water connection

Cold water connection

Minimum water flow inches inches

½ ” NPT

½ ” NPT

GPM (l/ min)

0.5 (1.9)

PSI (bar) 30 PSI (2.07 bar) Minimum recommended water pressure

Water valve material Fibreglass - reinforced polyamide (PA)

Bottom of heater Connections:

Dimensions

Depth 8.66” (220 mm)

Width inches

(mm) inches

(mm)

16.73” (425 mm)

Table 2

1) The freeze prevention kit is designed to provide protection for the water heater down to approximately 5°F for short term conditions only. It will not protect the appliance in areas where the temperature is routinely expected to be below freezing.

- The freeze prevention kit will not protect plumbing outside the appliance from freezing. Precautions should be taken.

6 720 644 947 (2014/11)

8 | Appliance details

Height inches

(mm)

25.75” (655 mm) pounds (kg) 35 pounds (16 kg) Weight

Gas types

Natural Gas

LP Gas

Venting

Natural Draft

Minimum height

Vertical termination feet 6* with no elbows

Vent diameter inches

Sidewall termination only with AQ4 power vent kit

5”

Table 2

1) To measure Gas Pressure, see Measuring Gas Pressure,

chapter 4.8, page 19.

3.2

Unpacking the 520PN heater

This heater is packed securely.

Before installing the unit, be certain you have the correct

heater for your type of Gas - Propane or Natural Gas.

Identification labels are found on the shipping box, and on the rating plate which is located on the right side panel of the cover.

Fig. 2 Rating plate

[A] Serial number

[B] Type of gas

The box includes:

• Mounting screws

• Product registration card

• Installation manual

• Incandescent particle tray

Do not lose this manual, there is a charge for a replacement.

Please complete and return the enclosed product registration card.

The 5520 PN is not approved or designed for:

• Manufactured (mobile) homes, RV's or boats

• Heating or other recirculating/pumping applications*

• Solar/preheat backup or high temperature booster use

• Installation in a bathroom or other occupied rooms normally kept closed.

*This includes domestic hot water circulator pump loop systems that may be installed in home hot water system prior to installing this unit. An approved recirculation design can be

found in chapter 4.10. Contact Bosch Water Heating if further

instruction is needed.

3.3

General rules to follow for safe operation

1. You should follow these instructions when you install your heater. In the United States: The installation must conform with local codes or, in the absence of local codes, the National Fuel

Gas Code ANSI Z223.1/NFPA 54.

In Canada: The Installation should conform with CGA

B149.(1,2) INSTALLATION CODES and /or local installation codes.

2. Carefully plan where you install the heater. Proper clearances must be followed.

3. The appliance must be isolated from the gas supply piping system by closing its individual manual gas shutoff valve (not supplied with heater) during any pressure testing at pressures in excess of ½ Psig (3.5 kPa).

The appliance and its gas connection must be leak tested before placing the appliance in operation.

4. Keep water heater area clear and free from combustibles and flammable liquids. Do not locate the heater over any material which might burn.

5. Correct gas pressure is critical for the optimum operation of this heater. Gas piping must be sized to provide the required pressure at the maximum output of the heater, while all the other gas appliances are in operation. Check with your local gas

supplier, and see chapter 4.7 and 4.8 to verify proper gas line

sizing.

6. Should overheating occur or the gas supply fail to shut off, turn off the gas supply at the manual gas shut off valve, on the gas line. Note: manual gas shutoff valve is not supplied with the heater.

7. Do not use this appliance if any part has been underwater.

Immediately call a qualified service technician to inspect the appliance and to replace any part of the control system and any gas control which has been underwater.

BOSCH is constantly improving its products, therefore specifications are subject to change without prior notice.

6 720 644 947 (2014/11) 520 PN

3.4

Dimensions and installation clearances

Appliance details | 9

Fig. 3 Dimensions in Inches and (mm)

[4] Heat exchanger

[5] Burner

[10] Temperature control

[11] Water valve

[20] Gas connection

[26] Output control

[36] Front cover

Dimensions inches (mm)

520 PN A B

16.73”

(425)

25.75”

(655)

Table 3 Dimensions in inches (mm)

C

13.15”

(334)

[37] Hole for fixing to wall

[38] Exhaust pipe to connector

[39] Draft diverter with flue gas monitor

[40] Gas valve

[49] Observation window

[102]Piezo

D

5.11”

(130)

E

21.25”

(540)

F

2.55”

(65)

G

1.18”

(30)

H

3/4”

520 PN 6 720 644 947 (2014/11)

10 | Installation instructions

Fig. 4 Minimum clearances

TOP (A)

FRONT (B)

BACK

SIDES

BOTTOM (C)

Table 4

Model 520PN

12 inches (306 mm)

4 inches (100 mm)

0 inches

4 inches (100mm)

12 inches (306 mm)

4 Installation instructions

4.1

Introduction

Please follow these instructions. Failure to follow instructions may result in:

• Damage or injury.

• Improper operation.

• Loss of warranty.

If you are unable to perform the tasks required to install this heater properly, please contact a locally licensed plumber or gas technician.

Please contact Bosch Water Heating with any questions.

4.2

Proper location for installing your heater

Carefully select the location of the water heater. For your safety and for proper heater operation, you must provide combustion air to the heater and a proper exhaust vent system.

1. Locate the heater where venting, gas and plumbing connections are feasible and convenient.

2. The hot water lines should be kept short to save energy.

Centrally locating the water heater is best. It is always best to have hot water lines insulated.

WARNING:

The water in this water heater is cold and always remains cold except for the times that hot water is being used. DO NOT

INSTALL IN AN AREA WHERE IT COULD

FREEZE.

▶ Drain the heater entirely if freezing temperatures are anticipated in area where heater is installed. See chapter

5.5 for draining instructions.

To prevent freeze damage from residual water in the heater, introduce short bursts of compressed air (20-40psi) through these connections to remove the residual water in the horizontal pipes and water valve.

WARNING:

▶ Flammable materials, gasoline, pressurized containers, or any other items or articles that are potential fire hazards must NOT be placed on or adjacent to the heater. The appliance area must be kept free of all combustible materials, gasoline and other flammable vapors and liquids.

WARNING:

▶ The heater must be isolated from the gas supply piping system during any pressure testing of that system at test pressures equal to or more than 0.5 psig.

WARNING:

▶ Place the heater in a location where water leaks will do NO DAMAGE to adjacent areas.

6 720 644 947 (2014/11) 520 PN

4.3

Heater placement and clearances

The 520 PN is design certified for installation on a combustible

wall (see 4.4 Mounting installation) provided the wall is not

covered with carpet or other fabric material. For installations in an alcove or closet, maintain the minimum clearances to combustible and non-combustible materials listed below. See

also Fig. 4.

A. Top 12 inches (306 mm)

B. Front 4 inches (100 mm)

C. Back 0 inches

D. Sides 4 inches (100 mm)

E. Bottom 12 inches (306 mm)

Installation instructions | 11

▶ Install incandenscent particle tray using screws provided

as shown in Fig. 5.

4.4

Mounting Heater

WARNING: before starting installation:

▶ check that there are no loose parts inside the appliance

▶ ensure that gas pipe, gas valve, and burner have no damage and are properly fitted.

▶ Read chapter 3.2 to verify proper gas

type and to check all parts are included in box.

Front cover should be removed in order to inspect components visually (see instructions below).

Fig. 5 Incandescent particle tray illustration

[1] Screws

[2] Incandescent particle tray

Mounting heater.

The 520 PN is design certified for mounting on a wall.

WARNING:

▶ Do not install this appliance on a carpeted wall.

The heater must be mounted on a wall using appropriate anchoring materials. If wall is a stud wall sheathed with plasterboard, it is recommended that support board(s), either

1x4’s or 1/2" (minimum) plywood first be attached across a pair of studs and then the heater should be attached to the

support boards, see Fig. 7.

▶ Secure the two included L shaped hooks to wall studs or

support board 13 1/4” apart. (See Fig. 7).

▶ Hang heater on two L shaped hooks. (See Fig. 8).

Remove cover and inspect.

▶ Remove the temperature control.

▶ Unscrew the cover fixing screws, see Fig. 6.

▶ Remove the outer case by sliding it forwards and then lifting upwards.

▶ Ensure that the flue terminal is clear.

▶ After inspection, replace front cover and tighten screws.

Install incandescent particle tray.

Fig. 6 Remove front cover

520 PN 6 720 644 947 (2014/11)

12 | Installation instructions

1

2

3

Fig. 7 Support board

[1] Wall studs

[2] Support board

[3] 1”x4” Space board

Fig. 8 Secure heater to wall

4.5

Combustion air requirements

The BOSCH water heater holds cold water in its copper heat exchanger and water valve when not in use. Because of this, any cold air that comes down through the unit's vent pipe is capable of freezing these components. This

Installation Manual specifies the minimum vertical vent pipe and the amount of combustion air required for this unit. When all requirements are followed, the unit will operate properly and safely. However, there may still be a risk of freezing due to negative draft if all the combustion appliances in the building or structure are not being supplied with a sufficient amount of make-up air. A wood stove or furnace can pull outside air down through the

BOSCH vent pipe and across the heat exchanger tubing. If the air is cold enough, the heat exchanger is at risk of freezing and bursting. Supplying more combustion air for all combustion appliances is the solution. Follow the instruction on venting and checking the adequacy of make up air. A HVAC specialist should be consulted on how to provide more combustion air if necessary. Observe the following instructions concerning combustion air.

Appliances located in unconfined spaces: a) An unconfined space is one whose volume is greater than 50 cubic feet per 1000 Btu per hour of the combined rating of all appliances installed in the space. That would be 5850 cubic feet for the BOSCH 520 PN alone.

b) Installations in structures that have been tightly constructed

(air infiltration rate of 0.40 ACH or less) must be provided for combustion air per the National Fuel Gas Code. Consult a HVAC specialist if your air infiltration rate is questionable.

Appliances located in confined spaces:

The confined space must be provided with two permanent openings, one commencing within 12 inches of the top and one commencing within 12 inches of the bottom of the enclosure.

Each opening must have a minimum free area of one square inch per:

• 1000 Btu/hr if all air is taken from inside the building.

• 2000 Btu/hr if all air is taken from the outside by horizontal ducts.

• 4000 Btu/hr if all air is taken from the outside by direct openings or vertical ducts.

Or the confined space must be provided with one permanent opening or duct that is within 12 inches of the ceiling of the enclosure. This opening must have a minimum free area of one square inch per:

• 3000 Btu/hr if all air is taken from the outside by a direct opening or vertical duct.

Louvers, grills and screens have a blocking effect. If the effective free area is not known, increase the sizes of your openings by 400% if your louvers are wood and by 135% if your louvers are metal. Refer to the National Fuel Gas Code for complete information. In buildings of tight construction all air should be taken from outside.

6 720 644 947 (2014/11) 520 PN

4.6

Venting

DANGER:

▶ Do not reduce the vent pipe size. Do not put an elbow directly on top of heater.

Failure to follow venting requirements may cause dangerous exhaust gases to enter living space.

▶ Minimum vent pipe diameter: 5 inches

▶ Minimum vertical vent height: 6 feet, with no elbows

▶ Establish 12 inch rise before any elbow

The heater must be vented to the outside following all local ordinances and specifications for installing a gas appliance vent or chimney. The heater must be located as close as practicable to a vertically rising chimney or vent that has a listed vent cap at its termination point. The venting system must be designed and constructed so as to develop a positive flow adequate to remove flue gasses to the outdoors. Consult the National Fuel Gas Code if the vent will have elbows or share venting with another natural draft appliance.

WARNING:

▶ Do not combination vent with a mechanically vented appliance.

4.6.1 Horizontal venting

WARNING:

▶ Horizontally venting to a vertically constructed vent stack along an outside wall of a building is not permissible.

Installation instructions | 13

▶ An approved gas vent connector must be attached to the top of the water heater and rise vertically at least 12" before entering into an approved gas vent connector elbow.

▶ The minimum vertical gas vent height allowed is 6 feet; horizontal vent connectors and elbows are not to be considered in the total gas vent height.

▶ All gas vent sections must be secured to each other with sheet metal screws and be properly supported.

Horizontal runs:

Any gas vent section that is greater than 45 degrees from the vertical is considered horizontal. Horizontal sections must slope upwards at least ¼ inch for every foot of its horizontal length and be properly supported. Keep the horizontal section short and avoid too many elbows. The maximum horizontal run allowed is half of the total vertical vent height; horizontal vent connectors and elbows are not to be considered in the total gas vent height.

Vent termination:

The gas vent constructed of double wall Type B gas vent must terminate above the roof surface with a listed vent cap at a

height that's in accordance with Fig. 11 and table 2, provided

it is at least 8 feet (2.4 m) from a vertical wall or similar obstruction. All other gas vents that are not able to terminate within the minimum specified height allowed must terminate not less than 2 feet (0.6 m) above the highest point where it's passed through the roof and at least 2 feet (0.6 m) higher than any vertical wall or similar obstruction within 10 feet (3.1 m).

WARNING:

▶ Horizontally venting to a sidewall vent terminator (without power vent) is not permissible.

A power vent, with a proof-of-draft safety interlock device, is required and is available for sidewall venting. Contact your dealer. In the Commonwealth of Massachusetts power vented applications must utilize proof-of-draft safety interlock device.

4.6.2 Vertical venting

▶ A 5 inch diameter gas vent constructed of double wall Type

B gas vent is recommended. A 6 inch vent is required in

elevations greater than 2000 feet, see Fig. 10. Under no

circumstances should the vent pipe be reduced in size.

520 PN 6 720 644 947 (2014/11)

14 | Installation instructions

ESTABLISH A ONE

FOOT RISE BEFORE

ANY ELBOWS

Fig. 9 Flat roof

[1] Listed vent cap

[3] Listed gas vent

[A] Minimum 6 feet (1,8m)

5” X 6” ADAPTOR

USED ON HIGH

ALTITUDE

Commonwealth of Massachusetts requires the use of a listed liner. Lining systems include approved clay flue lining, a listed chimney lining system or other approved material that will resist corrosion, erosion, softening, or cracking from exhaust flue gases at temperatures up to 1800 degrees F. The lining system must be listed for use with naturally drafting, draft hood equipped gas appliances. Follow local codes and refer to NFGC

54 and NFPA 58.

Existing interior masonry chimney

The metal gas vent pipe should be permanently mounted inside the masonry chimney. Double wall Type B gas vent is recommended. The masonry chimney may have to be tile or metal lined before the insertion of the gas vent pipe; check local codes for clarification. The lining material must be listed for use only with naturally drafting, draft hood equipped gas appliances. Follow manufactures instructions for installation of listed lining material. You may not vent any other fuel burning appliances into any free space remaining in the chimney. The minimum vertical gas vent length within the masonry chimney should be no less than 6 ft (1.8 m); the vent terminator should extend at least 3 feet (0.9 m) above where the chimney meets the roofline and at least 2 feet (0.6 m) higher than any vertical wall or similar obstruction within 10 feet (3.1 m). The top of the gas vent should have an approved vent terminator. See Fig.

12.

Fig. 10 Vent Adaptor for High Altitude Installations

Masonry chimney

Masonry chimneys shall be built and installed in accordance with NFPS 211 or local codes. A minimum 4" diameter gas vent pipe (metal double wall Type B), or an approved clay flue liner or a listed chimney lining system must be used when venting into a naturally drafting, internal masonry chimney. Local codes may require the use of both gas vent and an approved lining system when venting into a masonry chimney. The

6 720 644 947 (2014/11) 520 PN

Installation instructions | 15

ESTABLISH A

ONE

FOOT RISE

Fig. 11 Pitch roof

[1] Listed vent cap

[2] Lowest discharge opening

[3] Listed gas vent

[H] H (minimum) height from roof to lowest discharge opening

[X] Roof pitch is X/12

[A] Minimum 6 feet (1,8m)

GAS VENT TERMINATIONS FOR LISTED VENT CAPS

Roof pitch H (minimum) feet meters

Flat to 6/12

6/12 to 7/12

Over 7/12 to 8/12

Over 8/12 to 9/12

Over 9/12 to 10/12

Over 10/12 to 11/12

Over 11/12 to 12/12

Over 12/12 to 14/12

Over 14/12 to 16/12

Over 16/12 to 18/12

Over 18/12 to 20/12

Over 20/12 to 21/12

Table 5

1.0

1.25

1.5

2.0

2.5

3.25

4.0

5.0

6.0

7.0

7.5

8.0

0.30

0.38

0.46

0.61

0.76

0.99

1.22

1.52

1.83

2.13

2.27

2.44

Fig. 12 Masonry chimney

[1] Listed vent cap

[2] Vent connector

[3] Establish a one foot rise before any elbows

[A] Gas vent

4.7

Gas piping & connections

Before connecting the gas supply, check the rating plate on the right side of the heater to be sure that the heater is rated for the same gas to which it will be connected.

In the United States: The installation must conform with local codes or, in the absence of local codes, the National Fuel Gas

Code ANSI Z223.1/NFPA 54.

In Canada: The Installation should conform to CGA B149

INSTALLATION CODES and/or local installation codes.

Mount regulator to gas inlet pipe as shown in Fig. 13. The arrow

on the back of the regulator indicates the direction of gas flow and should point toward the appliance.

520 PN 6 720 644 947 (2014/11)

16 | Installation instructions

Fig. 13 Installation of Gas Pressure Regulator

Note: The 520 PN comes with a gas pressure regulator. Failure to install or altering the gas pressure regulator will be a violation of CSA certification of the unit. The regulator supplied with the heater is preset for the gas shown on the rating plate to the correct pressure. It is an appliance level regulator designed for

(low inlet) pressure (less than 1/2 Psig or 14" W.C.).

WARNING: DO NOT connect to an unregulated or high pressure propane line or to a high pressure commercial natural gas line.

WARNING: The heater must be isolated from the gas supply piping system during any pressure testing of that system at test pressures equal to or more than 0.5 psig. If overpressure has occurred, such as through improper testing of the gas lines or malfunction of the supply system, the gas valve must be checked for safe operation.

GAS CONNECTIONS

▶ Install a manual gas shut off valve, on the gas supply line.

▶ Install a union when connecting gas supply.

▶ Attach the appliance regulator to the inlet gas pipe.

▶ The minimum diameter required for any appliance connector used is ¾”.

▶ National Fuel Gas Code requires that a sediment trap (drip leg) be installed on gas appliances not so equipped. The drip leg must be accessible and not subject to freezing conditions. Install in accordance with the recommendations of the serving gas supplier.

When connections are made, check for gas leaks at all joints.

Apply some gas leak detection solution to all gas fittings.

Bubbles are a sign of a leak. A combustible gas detector may also be used to detect for leaks.

DANGER:

▶ If you have a leak, shut off the gas.

Tighten appropriate fittings to stop leak.

Turn the gas on and check again with a gas leak detection solution. Never test for gas leaks using a match or flame.

HIGH ALTITUDE INSTALLATION

The pressure regulator provided with the heater is adjusted to deliver the proper gas pressure (as indicated on the rating plate and in the manual for altitude up to 2000 feet (660 meters) above sea level. On appliances being installed above 2000 ft

(660 meters) elevation, the inlet gas pressure should be set at installation to the value shown below.

Note: The gas pressures specified below refer to pressures taken at the pressure tap on the gas inlet pipe just above the

regulator. See chapter 4.8 for measuring gas pressure.

MAXIMUM INLET GAS FLOW PRESSURE SETTING

Altitude

0’ - 2 000 ft

Nat. Gas inches

W.C.

5.7”

Liquid Propane inches W.C.

10.5”

2 000 ft - 4 500 ft 4.6” 8.4”

Table 6 Above 4.500 ft consult your local gas provider

GAS LINE SIZING

The gas supply piping should be sized according to the applicable code for a maximum draw of 117,000 BTUH.

Measure the length of gas supply line and use the tables in Fig.

14 or the gas line manufacturer’s sizing tables to determine the

pipe diameter necessary to accommodate the BTU demand of the unit. If there are more gas appliances drawing on the same line, size the gas line according to the total maximum amount of

BTU draw for all appliances.

Note: Under sizing the gas line may result in diminished output

and improper operation. See chapter 4.8 for the procedure to

confirm gas pressure.

6 720 644 947 (2014/11) 520 PN

Installation instructions | 17

FOR NATURAL GAS

Maximum Capacity of pipe in Cubic Feet of Gas per Hour for Gas Pressure of 0.5 Psig or less and a Pressure drop of 0.3 in Water

Column (0.75mbar).(Based on a 0.60 Specific Gravity Gas) Btu numbers given in thousands. Copper tubing is prohibited for use with Natural Gas in the Commonwealth of Massachusetts and not recommended elsewhere.

Follow boxed numbers for piping just one 520 PN (example: ¾” B.I. Natural Gas pipe for 20 ft (6.1m). will handle 190,000 btu’s

(55.7 kWh). For multiple appliances combine the total btu input load and then refer to applicable chart below.

Nominal

Iron

Pipe

3/4

1

1 - 1/4

Table 7

Internal

Diameter inches

0.824

1.049

1.380

10 20 30 40 50 60 70 80 90 100 125 150 175 200

278 190 152 130 115 105 96 90 84 79 72 64 59 55

520 350

1050 730

285

590

245

500

215

440

Lenght of Black Iron Pipe, Feet

195

400

180

370

170

350

160

320

150

305

130

275

120

250

110

225

Tube size,

Inches

1/2

EHD*

18

3/4 23

1 30

1 - 1/4 37

10

82

Length of Flexible Corrugated Stainless Steel Tubing (CSST), Feet

20

58

30

47

40

41

50

37

60

34

161

330

639

116

231

456

96

188

374

83

162

325

75

144

292

Table 8

* EHD = Equivalent Hydraulic Diameter. The greater the value EHD, the greater the gas capacity of the tubing.

68

131

267

100

210

520 PN 6 720 644 947 (2014/11)

18 | Installation instructions

FOR LP GAS

Maximum Capatity of Pipe in Thousands of BTU per Hour of Undiluted Petroleum Gases (at 11 inches Water Column Inlet Pressure)

(Based on a Pressure Drop of 0.5 Inch Water Column).

Tube size inches

1/2

EHD*

18

3/4 23

1 30

1 - 1/4 37

10

129

Length of Flexible Corrugated Stainless Steel Tubing (CSST), Feet

20

91

30

74

40

64

50

58

60

53

254

521

971

183

365

661

151

297

528

131

256

449

118

227

397

107

207

359

Table 9

* EHD = Equivalent Hydraulic Diameter. The greater the value EHD, the greater the gas capacity of the tubing.

Nominal

Iron Pipe

Size inches

Black Iron Pipe

Lenght of pipe, Feet

1/2

3/4

10

291

608

20

200

418

30

160

336

40

137

287

50

122

255

60

110

231

80

94

197

100

84

175

125

74

155

1 1145 787 632 541 480 434 372 330 292

Table 10

150

67

140

265

200

58

120

227

Outside diameter

Inch

3/8

1/2

5/8

3/4

10

39

92

199

329

20

26

62

131

216

30

21

50

107

181

40

19

41

90

145

Cooper (LP gas only)

Length of Tubing, feet

50 60

- -

70

-

37

79

131

35

72

121

31

67

112

80

-

29

62

104

90

-

27

59

95

Table 11

Maximum Capacity of Semi-Rigid copper Tubing in Thousands of BTU per Hour of Undiluted Liquefied Petroleum Gases (at 11 inches Water Column Inlet Pressure).

100

-

26

55

90

(Based on a Pressure Drop of 0,5 inch Water Column).

* Source National Fuel Gas Code NFPA 54, ANSI Z223.1

- No Additional Allowance is necessary for an ordinary number of fittings.

6 720 644 947 (2014/11) 520 PN

4.8

Measuring gas pressure

Connecting manometer

▶ Shut off gas.

▶ Remove front cover and locate inlet gas pressure

measuring point on the right side, see Fig. 14.

▶ Loosen screw from test point on the right side and connect manometer tube on test point.

Fig. 14 Gas pressure measuring point

[A] Inlet tap

Static pressure test

▶ Turn gas supply back on.

▶ Record static gas pressure reading on back page of manual.

Operating pressure test

▶ Turn on all hot water taps served by the water heater.

▶ Run high hot water flow rate.

▶ Set flow control knob fully clockwise.

▶ Set slide control to the right.

▶ Record operating gas pressure reading on back page of manual.

Gas pressures lower than 5.7" W.C. for Natural Gas or 10.5"

W.C. for LP Gas will result in insufficient degree rise to the hot water being used, and must be corrected. See Gas Line Sizing

under chapter 4.7.

Installation instructions | 19

4.9

Water connections

When facing the heater, the ½ ” cold water inlet is on the bottom right and the hot water outlet is on the bottom left.

▶ Install unions or the Webstone service valves when connecting plumbing to the water heater. This will facilitate any necessary cleaning and servicing.

Although water piping throughout your structure may be other than copper, we recommend that copper piping or suitably rated stainless steel flex line piping be used for at least three feet before and after the heater (follow local codes if more stringent). Never sweat any rigid piping directly to or beneath the water connections, damage can occur to the internal water valve from heating of the pipe. Plastics or other PEX type plumbing line materials are not recommended for connecting directly to the water heater. Keep water inlet and outlet pipes to no less than ½" (12.7mm) diameter to allow the full flow capacity.

It is recommended that all water piping below the heater be properly insulated to avoid heat loss.

If the cold and hot connections to the heater are reversed, the heater will not function. Be certain there are no loose particles or dirt in the piping. Blow out or flush the lines before connecting to the water heater. Full port valves should be installed on both the cold water supply and hot water outlet

lines to facilitate servicing the heater (see Fig. 16). For

installation on a private well system with the use of a pressure tank, the lowest pressure range setting recommended is 30-50 psi (2.07 and 3.45bar).

Connecting the pressure relief valve (PRV)

A listed pressure relief valve must be installed at the time of installation. No valve is to be placed between the PRV and the heater. No reducing coupling or other restriction may be installed in the discharge line. The discharge line must be a minimum of 4” above a drain and installed such that it allows complete drainage of both the PRV and the line.

The location of the PRV must be readily accessible for servicing or replacement, and be mounted as close to the water heater as

possible. See Fig. 15 To install the PRV, a suitable fitting

connected to an extension on a “T” fitting can be sweated to the hot water line.

Support all piping.

520 PN 6 720 644 947 (2014/11)

20 | Operation instructions

5

1

2

3

4

Fig. 15 Plumbing connections and pressure relief valve shown with optional Webstone service valves

4.10 Recirculation application

Since recirculation through the heater is not permissible, the following drawing is provided to outline a proper recirculation application using the BOSCH PRO water heater with an Ariston minitank. This schematic is for illustration only and must not be used for actual installation without appropriate engineering and technical advice from a professional properly licensed in locality where the installation is made.

6720608030-19.4Av

Fig. 16 Recirculation application

[1] Full port isolation valve

[2] Circulator

[3] Check valve

[4] PRV

[5] Expansion tank

The use of a small electric mini-tank (4-6 gallon size) should be used for this application and designed so the pump will circulate the water through the mini-tank and the building's hot water return loop only. A timed or thermostatically controlled operation of the pump is commonly done. The 520 PN should be plumbed in line before the mini-tank water heater. Contact

Bosch Water Heating if further instruction is needed.

5 Operation instructions

5.1

For your safety read before operating your water heater

WARNING:

▶ If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury or loss of life.

Upon initial installation, existence of air in the gas supply line and in the water line may cause some ignition delay. In that case, repeat the ignition process until all the air has been purged.

A. This appliance employs a piezo-igniter to light the pilot burner. When lighting the pilot, follow these instructions exactly.

B. What to do if you smell gas.

6 720 644 947 (2014/11) 520 PN

Operation instructions | 21

▶ Slide the gas valve button to the position .

WHAT TO DO IF YOU SMELL GAS

▶ Close gas valve. Open windows.

▶ Do not try to light any appliance.

▶ Do not touch any electric switch; do not use any phone in your building.

▶ Immediately call your gas supplier from a neighbors phone.

Follow the gas supplier’s instructions.

▶ If you cannot reach your gas supplier, call the fire department.

C. Use only your hand to push in the gas control buttons. Never use tools. If a button will not push in, check to make sure the buttons are being pushed in the proper sequence. Follow these instructions exactly. If control button(s) are jammed, close the heater’s individual manual shutoff valve and call a qualified service technician. Forced or attempted repair may result in a fire or explosion.

D. Do not use this appliance if any part has been under water.

Immediately call a qualified service technician to inspect the appliance and to replace any part of the control system and any gas control which has been under water.

5.2

Lighting instructions

▶ STOP! Read the previous safety information.

▶ The gas valve must be turned off by sliding the gas valve button to all the way to the left.

Fig. 18

▶ Fully depress gas valve button.

Fig. 19

▶ With the gas valve button fully depressed, light pilot by pushing the piezo button. This step may have to be repeated.

Fig. 17

▶ Wait five (5) minutes to clear out any gas. If you smell gas,

STOP! Follow “B” in the safety information above on this plate. If you don’t smell gas, go to next step.

▶ The pilot burner window is located in the front center of the cover.

Fig. 20

520 PN 6 720 644 947 (2014/11)

22 | Operation instructions

▶ Observe the pilot flame through the peephole. The gas valve button should be held down for at least 15 seconds with pilot burning before releasing. When the gas valve button is released, the pilot should continue to burn.

- If the gas valve button does not pop out when released, stop and immediately call your service technician or gas supplier.

- If pilot does not stay lit, repeat all steps.

- If pilot will not stay lit after several tries, slide the gas valve button all the way to the left and call service technician or gas supplier.

▶ The heater will now fire at minimum power when water is drawn at a rate greater than the required activation flow rate.

Note: If main burner should fail to ignite, make sure pilot is burning. If not, repeat lighting steps.

Note: The 520 PN operates in two modes. See SETTING THE

WATER TEMPERATURE.

5.3

To turn off appliance

▶ Slide the gas valve button all the way to the left and turn off the installer supplied manual gas shutoff on the supply line to the heater.

Fig. 22

Knob position

Degree rise

Activation rate

Max flow rate

Clockwise

90 °F

0.5 GPM

2.0 GPM

Counterclockwise

45 °F

1.1 GPM

3.7 GPM

Table 12 Temperature rise (slide control to the right)

As the temperature adjustment knob is turned counterclockwise, the output temperature will lower and the activation rate will be raised. Turning the knob clockwise will raise the temperature and lower the activation rate.

Gas control slide button

The gas control slide button adjusts temperature by adjusting how much gas is allowed to flow to the burners.

As the slide is adjusted to the left, the output temperature will lower, with the lowest setting being the small flame position.

Fig. 21

5.4

Setting the water temperature

The 520 PN has a gas control that modulates burner input in response to flow. Its purpose is to ensure that the hot water temperature will remain steady, although the water flow demand might vary. The output temperature can be adjusted with either the temperature adjustment knob or the gas control slide.

Temperature adjustment knob

The temperature adjustment knob on the front bottom of the

heater (see Fig. 22) adjusts temperature by adjusting flow capacity. See table 12 for details.

Fig. 23

The hottest position is the highest flame position all the way to the right.

6 720 644 947 (2014/11) 520 PN

Maintenance and service | 23

6 Maintenance and service

6.1

Maintenance intervals

WARNING:

▶ Failure to perform recommended maintenance may result in complete failure of the unit over time.

The warranty does not cover failures due to improper or insufficient maintenance.

Fig. 24

5.5

Draining water from heater

If there is a risk of freezing, proceed as follows:

▶ Remove the retaining clip from threaded bushing (Fig. 25,

[pos. 1]).

▶ Remove threaded bushing (Fig. 25,[pos. 2]) from water

valve.

▶ Empty the appliance of all water.

Fig. 25 Drain plug and filter location

[1] Retaining clip

[2] Threaded bushing

The 520 PN requires periodic maintenance. The below time maintenance intervals should kept the unit operating for many years.

Every year

▶ Inspect inlet water filter screen (

see chapter 6.2)

▶ Inspect pilot assembly and flame (

see chapter 6.3)

▶ Inspect burner assembly (

see chapter 6.4)

Every 2 years

▶ Inspect heat exchanger fins for soot, debris or blockage.

Clean if necessary (

see chapter 5.5)

▶ Lubricate and clean water valve (

see chapter 6.2)

Every 3 to 5 years

▶ Rebuild water valve (

see chapter 6.2)

▶ Clean pilot assembly and clean or replace orifice ( see

chapter 6.3)

6.2

Water valve

The water valve is the main control that tells the heater to fire.

If the periodic maintenance is neglected, more costly damage may occur over time.

Inspecting inlet water filter screen

Shut off the installer supplied cold water isolation valve to the heater. If one is not installed, install before proceeding. Open the nearest hot water tap to drain the plumbing lines. Position a bucket under the heater's water valve assembly to catch any water that may drain from the heater. Remove the filter retaining pin located at base of water valve (

see Fig. 25).

Remove the threaded bushing to access the cylindrical filter inside. Remove filter, clean with water and inspect for damage.

If the filter is at all damaged, it should be replaced.

Lubricating the water valve

A more detailed instruction is available on our website at www.bosch-climate.us. Shut off the installer supplied cold water isolation valve to the heater. If one is not installed, install before proceeding. Open the nearest hot water tap to drain the

520 PN 6 720 644 947 (2014/11)

24 | Maintenance and service plumbing lines. Position a bucket under the heater's water valve assembly to catch any water that may drain from the heater. Disconnect the inlet water pipe going to the back of the water valve. Disconnect the water pipe leading out of water valve to the heat exchanger. Do this by removing the retaining pin on water valve assembly and pulling the pipe free from the water valve. Loosen the two set screws at the bottom of the water valve where it connects to the gas valve. If the set screws are seized, STOP and call Bosch tech support before proceeding. Forcing and snapping seized set screws may cause irrevocable damage to the water valve and gas valve assemblies. Remove the water valve by pulling it to the right.

Separate the two halves of the water valve by removing the five screws on the left side of the water valve. Apply lithium or

faucet & valve grease to the pushrod and o-ring. (See Fig. 28).

Inspect the venturi and clean if necessary. (see Fig 28).

Rebuilding the water valve

Several parts within the water valve should be replaced every 3 to 5 years depending on water quality and usage. The parts list and instructions can be found on our website at www.boschclimate.us. Failure to rebuild the water valve can result in decreased performance or damage to the heater.

6.3

Pilot

Inspecting pilot

The pilot should burn with a clean sharp blue flame. The flame should fully engulf the tip of the thermocouple. If it does not, clean the pilot assembly per procedure below.

Cleaning pilot assembly

Shut off gas supply to the heater using installer supplied manual gas shutoff. Locate pilot gas tubing mounted in the center of the burner assembly. At the base of the pilot gas tubing there is a retaining clip. Release pilot gas tubing from this clip. Push upwards on other end of pilot gas tubing to release it from burner mount. Remove brass hex headed pilot orifice from gas valve (located near base of pilot gas tubing).

Soak orifice and pilot gas tubing in carburetor cleaner for 30 minutes. Dry off and reinsert orifice in gas valve. If heater is an

LP unit, replace orifice. Reinstall the pilot gas tubing following removal instructions in reverse. Open gas supply and return heater to service.

CAUTION:

▶ Do not ream or poke orifice as it will enlarge orifice opening.

6.4

Main burners

The main burner flames should be blue, with a more intense blue cone in the center core. Yellow flames could be a sign of wrong size gas orifices or dirty burners, a blockage on the heat exchangers fins. If some burners have yellow flames while others have blue flames, it is likely that dust, lint or spider webs have partially clogged the burner venturis. To clean the burners, contact a gas service person.

6.5

Vent assembly / heat exchanger

Inspect the draft hood and heat exchanger fins for signs of soot build-up or any other foreign material such as spider webs.

Clean out any debris found in the vent hood and/or heat exchanger fins. Signs of soot indicate insufficient combustion air or exhaust draft. Check for vent assembly blockage or combustion air blockage on the underside of the unit.

6.6

Mineral scale build-up

The 520 PN, when operated at lower temperatures settings, does not accumulate mineral build-up. If however, the heater is used at the higher temperature settings and the water has a high mineral content, periodic descaling may be necessary.

The heating coils should be flushed with a descaling solution.

6.6.1 Descaling heat exchanger

1. Disconnect electrical supply from the water heater.

2. Shut off the water supply to the water heater using (installer supplied) isolation valve.

3. Open hot water taps to drain and relieve pressure from the plumbing system.

4. Drain water from the unit's heat exchanger by disconnecting inlet and outlet water connections.

5. Connect the line (A) from the outlet of the circulating pump

(installer supplied) to the inlet water fitting on the water heater.

6. Using another line (B), connect to the water outlet fitting on the water heater. Route the other end of this line into a descaling reservoir.

7. Using a 3rd line (C) from the descaling reservoir, connect to the inlet side of circulating pump. Verify there is a filter on the end of the line in the descaling reservoir.

8. Make sure all connections are "hand tight"

9. Fill tank with descaling solution so lines inside are submersed. We recommend a straight white vinegar solution. If using a commercial descalant, refer to manufacturer's instructions on dilution with water.

10. Operate the circulating pump.

11. Make sure there are no leaks and the solution is flowing from the descaling reservoir through the heat exchanger and returning to the reservoir.

12. Run solution through the heat exchanger until the solution returning to the descaling reservoir comes out clear. (Changing to a fresh solution may be necessary during this process).

6 720 644 947 (2014/11) 520 PN

13. Disconnect all lines and drain all solution from heat exchanger. Properly discard of solution.

14. Position a container below the hot water outlet and connect cold water supply. Open cold water supply isolation valve and flush heat exchanger with clean water.

15. Shut cold water isolation valve and reconnect hot water supply to the water heater.

16. Reconnect electrical supply to unit, open water isolation valves, and return the unit to service.

Fig. 26

7 Troubleshooting

7.1

Introduction

Many of the questions customers ask regarding operation of this unit can be answered by following the troubleshooting steps as outlined below. Visit our web site at www.boschclimate.us for more detailed troubleshooting. For best results, perform each step before proceeding to the next. The suggested solutions may require that the cover be taken off.

(

See chapter 4.4).

7.2

Pilot does not light

1. Verify gas supply is on at Natural Gas meter or Propane Tank.

Make sure all manual gas shut off valves are in the open position. Have licensed gas technician confirm adequate gas

Troubleshooting | 25 pressure at the inlet tap (

chapter 4.9). If gas is not present,

verify manufacturer supplied Maxitrol regulator is in the upright position. The arrow on the back of the regulator should point in the same direction as gas flow.

2. If the unit was just installed or the gas lines have been worked on, there may be air in the gas line. Centered in the sparking position, hold down the gas control slide button while hitting the pilot igniter button every few seconds. It may take several minutes to bleed air out of the gas line.

3. Verify a spark is being thrown at pilot area while gas control slide button, centered in the single flame position, is being firmly depressed. Repeatedly push in pilot igniter button to light the pilot. If no spark is present, verify proper wire connection to the electrode.

4. Pilot assembly may be blocked. Clean or replace the pilot orifice (

chapter 6.3).

7.3

Pilot lights, but goes out when button is released

1. When lighting pilot ensure the gas control slide button is fully depressed and held down for at least 20 seconds after pilot is lit.

2. Verify gas type indicated in rating sticker located on right hand side of cover, coincides with the gas type you are using.

NG is a natural gas unit and LP is for liquid propane.

3.If using a power vent, check the safety spillage switch reset button (the safety spillage switch is wired through the water heater's thermocouple circuit). The spill switch should be located at top of water heater close to draft diverter (Consult manual that came with powervent).

4. Check all connections of the pilot safety circuit. The pilot safety circuit consists of a thermocouple, overheat sensor

(ECO), flue gas sensor, safety spillage switch (models with

Powervents only) and the electromagnet (See parts diagram for locations). Clean sensor connections with light sandpaper if corrosion is evident. The electromagnet connection is 5mm nut from the thermocouple which screws into a larger 17mm nut.

Tighten both nuts snugly but do not over tighten.

5. Pilot flame should be blue in color and completely engulfing the tip of the thermocouple. If not, have a licensed gas technician verify gas pressure is in accordance with manufacturer's specifications (

chapter 4.9) and clean or

replace the pilot orifice (

chapter 6.3).

6. Have a licensed gas technician verify the proper operation of the thermocouple by measuring the millivoltage from the thermocouple lead to ground. The proper reading should be

24mVDC or greater. If the reading is lower, the thermocouple may be defective. Call Bosch Water Heating for further instructions.

520 PN 6 720 644 947 (2014/11)

26 | Troubleshooting

7.4

Pilot goes out during or after hot water use

1. Pilot outage during use typically results from the unit's safety overheat/high limit sensors interrupting the pilot circuit. The

520 PN does not have a thermostat. If inlet water is preheated, the unit will overheat, stopping the flow of gas. Plumb inlet with a cold water line only.

2. Failure to vent properly by reducing pipe diameter, improper use of elbows or not meeting required vent length are common causes that deactivate the pilot safety circuit. Confirm venting is in accordance with manufacturer's specifications ( see

chapter 4.7).

3. Confirm the combustion air requirements are being met in accordance with manufacturer's specifications ( see chapter

4.6). Proper venting and combustion air will ensure a proper

draft.

4. Confirm that the burners in the water heater go off immediately when the hot water is turned off. If they remain on or shut down slowly, then the overheat sensor (ECO) will interrupt the pilot circuit and shut off all gas to the heater. The water valve assembly, which actuates the burners, may be dirty and require periodic maintenance (every 2 - 5 years depending on water quality and use) (

see chapter 6.2).

5. Check all connections of the pilot safety circuit. The pilot safety circuit consists of a thermocouple, overheat sensor

(ECO), flue gas sensor, safety spillage switch (models with

Powervents only) and the electromagnet (See parts diagram for locations). Clean sensor connections with light sandpaper if corrosion is evident. The electromagnet connection is 5mm nut from the thermocouple which screws into a larger 17mm nut.

Tighten both nuts snugly but do not over tighten.

6. Verify pilot flame completely engulfs the thermocouple tip. If pilot is too small, clean pilot orifice (

see chapter 6.3).

7. If the water has a high mineral content, the heat exchanger may be scaled internally. This restricts the water path, causing the water to over heat which shuts all gas off to the heater.

Instructions for descaling the heat exchanger are available at www.bosch-climate.us.

8. If steps 1 through 7 do not correct the problem, then confirm that the gas pressure is adequate. Ensure gas pressure is in accordance with manufacturer's specifications ( see

chapter 4.9). A gas pressure reading is needed to proceed

further. Contact your original installer or a licensed gas technician to obtain this reading.

7.5

Burners do not light with water flow

1. Verify the pilot is lit.

2. Verify the gas control slide button is in middle position.

3. Verify the cold water supply is connected to the right side of the heater.

4. Close installer supplied cold water shut off valve (if none installed, install before proceeding). Open all hot water taps supplied by the heater. Wait 5 minutes and check all taps. Any water running is a sign of a plumbing crossover. Consult a local plumber or service person for help in correcting a plumbing crossover.

5. Verify flow through the water heater is sufficient. Turn temperature adjustment knob all the way clockwise. Fully open a hot water faucet and fill a quart container. If the container fills in 30 seconds or less, the flow rate (1/2 gallon per minute) is sufficient to activate the heater.

6. Inspect the water path outside of the heater for obstructions. Make sure all outlets (i.e. showerheads, faucet aerators and whole house filters) are clear of debris. Also, the water heater's inlet filter screen should be inspected and cleaned (

see chapter 6.2).

7. The water valve assembly, which actuates the burners, requires periodic maintenance (every 2 - 5 years depending on water quality and use) (

see chapter 6.2).

7.6

Hot water temperature fluctuates at tap

1. Close off installer supplied cold water shut off valve (if none installed, install before proceeding). Open all hot water taps supplied by the heater. Wait 5 minutes and check all taps.

Water running is a sign of a plumbing cross-over. Consult a local plumber or service person for help in correcting a plumbing crossover.

2. Check for a clogged inlet water filter screen ( see

chapter 6.2).

3. Hot water is very hot out of the tap, requiring a lot of cold water to be added with it in order to attain a usable hot water temperature. The addition of too much cold will overpower and slow the flow within the tankless water heater, decreasing it below activation point, which shuts off the burners. The end result is nothing but cold water coming out of the outlet.

Reduce the need for cold water mix by setting the gas slide control button towards the single flame position for lower hot water temperatures. If the problem persists, go to www.boschclimate.us for a more detailed service bulletin on this problem.

4. The 520 PN is designed to modulate gas flow to the burners when water flow varies. If the water pressure in the home is erratic and the water flow is not consistent while a tap is opened, then the temperature of hot water will fluctuate. The minimum water pressure for the home should be 30psi or greater. For installation on a private well system with the use of a pressure tank, the lowest pressure range setting recommended is 30-50 psi (2.07-3.45 bar). The use of a pressure reducing/regulating valve before the water heater

(directly after pressure tank on well systems) is an effective way to maintain constant water pressure to the water heater.

6 720 644 947 (2014/11) 520 PN

Watts brand 25AUB- ¾" or N35B -¾" pressure reducing/ regulating valves or equivalent are suggested.

5. If the inlet water temperature is not steady then the hot water temperature from the water heater will fluctuate. The

520 PN modulates its burners when the flow rate is changed; it does not have a thermostat and will not adjust to changes in inlet water temperature.

6. If the inlet water temperature to the water heater is above

70°F, the heater may produce outlet temperatures that are too hot for most users. A temperature balance shower valve can automatically mix in cold water to reduce such hot water temperature. This can slow the flow within the tankless water heater, decreasing it below activation point, which shuts off the burners. In the event of any temperature instability with the use of a temperature balance shower valve, refer to shower valve manufacturer's instructions for internal adjustment setting. An adjustment should be made to minimize the amount of cold water the valve is adding.

7. The gas pressure also needs to be stable and adequate.

Ensure gas pressure is in accordance with manufacturer's specifications (

see chapter 4.9). A gas pressure reading is

needed to proceed further. Contact your original installer or a local certified gas technician to obtain this reading.

8. A water valve, which has not been serviced, may be struggling to keep the gas valve open. The water valve requires periodic maintenance (every 2-5 years depending on water quality and use) (

see chapter 6.2).

7.7

Water is too hot

1. Verify gas type indicated in rating sticker located on righthand side of cover, coincides with the gas type you are using.

NG is a natural gas unit and LP is for liquid propane.

2. Adjust the gas control slide button from three flame position towards the one flame position for cooler temperatures. If the water is still too hot, the temperature adjustment knob on the water heater maybe set too high. Lower the setting and test water temperature. This dial turns counter clockwise for lower temperatures and clockwise for higher temperatures.

3. Inlet water is preheated. This model does not have a thermostat and thus will not modulate flame height in order to prevent over heating. It is designed for a cold water feed only.

Replumb the heater with cold water to the inlet.

4. Increase the flow rate. Restrictions in the water path can slow the flow of water through the heater, resulting in very hot outlet temperatures. Restrictive showerheads and faucet aerators should be cleaned out or upgraded with less restrictive ones. In addition, the water heater's inlet filter should be cleaned and inspected (

see chapter 6.2).

5. If water is still too hot, consult service bulletins on www.bosch-climate.us to lower outlet temperatures further.

Troubleshooting | 27

6. If the water has a high mineral content, the heat exchanger may be scaled internally. This restricts the water path, causing the water to boil and produce extremely hot temperatures.

Instructions for descaling the heat exchanger are available at www.bosch-climate.us.

7.8

Water is not hot enough

1. Verify gas type indicated in rating sticker located on righthand side of cover, coincides with the gas type you are using.

NG is a natural gas unit and LP is for liquid propane.

2. Flow at one particular tap is too great or too many fixtures are running at one time. Lower flow to stay within heater's specifications.

3. Ensure the gas control slide button is all the way to the right.

In addition, the temperature adjustment knob on water heater maybe set too low. Turn the knob clockwise for higher temperatures and test the water temperature.

4. Shut off installer supplied cold water shut off valve (if none installed, install before proceeding). Open all hot water taps supplied by the heater. Wait 5 minutes and check all taps. Any water running is a sign of a plumbing crossover. Consult a local plumber or service person for help in correcting a plumbing crossover.

5. Inspect the water path outside of the heater for obstructions. Make sure all outlets (i.e. showerheads, faucet aerators and whole house filters) are clear of debris. Also, the water heater's inlet filter screen should be inspected and cleaned (

see chapter 6.2).

6. The water valve may be dirty, prohibiting it from fully opening the gas valve. This part needs to be periodically serviced (every 2-5 years depending on water quality and use)

(

see chapter 6.2).

7. Gas pressure is too low. Ensure gas pressure is in accordance with manufacturer's specifications ( see

chapter 4.9). A gas pressure reading is needed to proceed

further. Contact your original installer or a local certified gas technician to obtain this reading.

7.9

Burners ignite without hot water flow

1. The water valve may be dirty and sticking, prohibiting it from fully closing the gas valve. This part needs to be periodically serviced (every 2-5 years depending on water quality and use)

(

see chapter 6.2).

7.10 Low hot water pressure

1. Confirm adequate flow rate through the unit. With cold supply shut off to the unit, disconnect hot outlet side to the unit. Place a half gallon jug under hot outlet to catch water.

Open cold supply and measure flow rate out of the unit. With temperature adjustment knob set all the way clockwise, the

520 PN 6 720 644 947 (2014/11)

28 | Protecting the environment flow rate should be close to 2gpm, filling the jug in 15 seconds.

With the temperature adjustment knob set all the way counterclockwise, the flow rate should be close to 4gpm, filling the jug in 7 seconds. If the flow rate is not adequate, inspect and clean the inlet filter screen (

see chapter 6.2).

2. Confirm the incoming water pressure to the unit is above the required 30psi.

3. Inspect the water path outside of the heater for obstructions. Make sure all outlets (i.e. showerheads, faucet aerators and whole house filters) are clear of debris.

4. Be sure to run only one major application at a time with this unit. Opening too many taps at one time can disperse water flow resulting in a diminished flow/pressure at all outlets.

5. If the water has a high mineral content, the heat exchanger may be scaled internally. This restricts the water path, causing diminished water flow. Instructions for descaling the heat exchanger are available at www.bosch-climate.us.

7.11 Noise when heater is running

1. Confirm adequate flow rate through the unit. With cold supply shut off to the unit, disconnect hot outlet side to the unit. Place a half gallon jug under hot outlet to catch water.

Open cold supply and measure flow rate out of the unit. With temperature adjustment knob set all the way clockwise, the flow rate should be close to 2gpm, filling the jug in 15 seconds.

With the temperature adjustment knob set all the way counterclockwise, the flow rate should be close to 4gpm, filling the jug in 7 seconds. If the flow rate is not adequate, inspect and clean the inlet filter screen (

see chapter 6.2).

2. Inspect the water path outside of the heater for obstructions. Make sure all outlets (i.e. showerheads, faucet aerators and whole house filters are clear of debris.

Restrictions in the water path can slow water flow through the heat exchanger causing it to boil and make noise.

3. If the water has a high mineral content, the heat exchanger may be scaled internally. This restricts the water path, causing the water to boil resulting in noise and overheating.

Instructions for descaling the heat exchanger are available at www.bosch-climate.us.

7.12 Burners do not operate cleanly; yellow flames when operating

1. Verify gas type indicated in rating sticker located on righthand side of cover, coincides with the gas type you are using.

NG is a natural gas unit and LP is for liquid propane.

2. Gas pressure may be inadequate resulting in improper combustion. Ensure gas pressure is in accordance with manufacturer's specifications (

see chapter 4.6). A gas

pressure reading is needed to proceed further. Contact your original installer or a licensed gas technician to obtain this reading.

3. For proper combustion at high elevations the inlet gas pressure should be set at installation to the value shown in

table 3 (while operating at maximum BTU). A gas pressure

reading is needed to proceed further. Contact your original installer or a licensed gas technician to obtain this reading.

4. Ventilation is not adequate. Ensure adequate combustion air is being supplied to the unit in accordance with manufacturer's specifications (

see chapter 4.6).

5. Make sure the water heater is vented properly. Check for proper draft and ensure venting is in accordance with manufacturer's specifications (

see chapter 4.7).

6. The water heater has burners much like a furnace. It is essential that they remain clean and are supplied with adequate air for combustion. If the flames burn yellow or orange, it is strongly recommended that the burners be removed from the unit and cleaned. Once the burners are removed, the fins in the top of the heat exchanger can be accessed and brushed or vacuumed clean. Instructions to remove burners are available at www.bosch-climate.us.

8 Protecting the environment

Packing

The packing box may be fully recycled as confirmed by the recycling symbol .

Components

Many parts in the heater can be fully recycled in the end of the product life. Contact your city authorities for information about the disposal of recyclable products.

Saving water resources:

▶ Make sure you close all the taps after any use. Avoid leaving the taps dripping. Repair any leaking tap.

▶ Set the water heat to the temperature you want. This way you have the precise water flow needed (mixing cold water to regulate temperature will increase the water flow with consequent waste of water).

For increased safety shut off the appliance from the main water supply if your are staying away from home for a considerable time.

At below freezing temperatures, disconnect the plumbing connections to the heater and allow the heater to drain.

To prevent any freeze damage, introduce short bursts of compressed air (20-40 psi) through these connections to remove the residual water in the horizontal pipes and water valve.

6 720 644 947 (2014/11) 520 PN

Follow instructions in

chapter 5.5 to remove any additional

water remaining in the watervalve and heat exchanger.

9 Interior components and diagram parts list

9.1

Interior components

Interior components and diagram parts list | 29

Fig. 27 Functional scheme

[4] Heat exchanger

[5] Burner

[10] Temperature adjustment selector

[11] Water valve

[20] Gas connection

520 PN

[22] Flexible hot outlet

[26] Gas control slide

[30] Pilot gas tubing

[102]Piezo

6 720 644 947 (2014/11)

30 | Interior components and diagram parts list

9.2

Components diagram

Fig. 28 Components Diagram

6 720 644 947 (2014/11) 520 PN

Interior components and diagram parts list | 31

9.3

Parts list

6

7

4

5

8

2

3

Item Description

1 Front cover

Shield

Temp control knob

Draft Diverter

Exhaust pipe union Ø128

Angle bracket

Trade mark badge

Heat exchanger

9 Cold water pipe

10 Main burner NG

10 Main burner LP

11 Connector

12 Piezo clip (x10)

13 Sparking plug

14 Pilot gas pipe

15 Tube (x10)

16 Pilot screen

17 Gas valve LP

17 Gas valve NG

18 Throttle housing

19 Washer (x10)

20 Pilot injector LP

20 Pilot injector NG

21 Pilot valve

22 Poppet valve head (2) NG

22 Poppet valve head (3) LP

23 Electromagnet

24 Electromagnet cap

25 Valve operation housing

26 Guide plate

27 Gas pressure regulator LP

27 Gas pressure regulator NG

28 Water valve

29 Watervalve pushrod (10x)

30 Diaphragm (L)

Table 13

8 707 021 396 0

8 707 021 395 0

8 705 502 067 0

8 701 004 044 0

8 708 200 326 0

8 708 200 327 0

8 708 500 301 0

8 708 500 358 0

8 708 500 359 0

8 707 201 028 0

8 703 305 283 0

8 708 008 069 0

8 701 000 380 0

8 707 406 083 0

8 707 406 084 0

8 707 006 344 0

8 703 204 051 0

8 700 503 084 0

Reference

8 738 708 496

8 738 708 497

8 702 000 295 0

8 705 505 442 0

8 705 504 046 0

8 708 003 192 0

8 701 103 135 0

8 705 406 386 0

8 700 715 061 0

8 708 120 618 0

8 708 120 619 0

8 705 209 062 0

8 701 201 019 0

8 748 107 089 0

8 700 707 369 0

8 740 609 002 0

8 700 507 067 0

Item Description

31 Inlet water connection

32 Selector screw

33 Piezo igniter

34 Fixing bracket

35 Ignition lead

37 Flue gas safety device

38 Washer (x10)

39 Heat exchanger washer

40 Threaded bushing

41 Connector

42 Water filter

43 Outlet Hose

44 Water connection clip

45 Plunger

46 Volumetric water governor

47 ECO

48 Temperature limiter

49 Venturi

50 Hot water pipe

51 Gas supply pipe

52 Cover

Table 13

Reference

8 700 306 110 0

8 708 500 304 0

8 708 108 051 0

8 701 302 181 0

8 704 401 040 0

8 707 206 445 0

8 701 004 043 0

8 700 103 658 0

8 700 306 148 0

8 700 306 187 0

8 700 507 059 0

8 700 703 139 0

8 701 201 020 0

8 703 502 039 0

8 705 705 034 0

8 707 206 017 0

8 707 206 435 0

8 708 205 279 0

8 700 715 178 0

8 700 715 351 0

8 705 500 105 0

520 PN 6 720 644 947 (2014/11)

32 | LIFETIME LIMITED WARRANTY FOR BOSCH TANKLESS WATER HEATERS

10 LIFETIME LIMITED WARRANTY FOR BOSCH TANKLESS WATER HEATERS

MODELS COVERED

This limited warranty is provided by Bosch Thermotechnology

Corp. (BTC) and covers models 520 PN (hereinafter referred to as "Water Heater"). This warranty is provided as long as the

Water Heater remains in the possession of the original purchaser and installed at its original place of installation.

WARRANTY COVERAGE

HEAT EXCHANGER -Limited Warranty

BTC warrants that the heat exchanger will remain free of leaks for Fifteen (15) years from the date of original installation provided that the heat exchanger is properly maintained by a qualified heating contractor and the other conditions of this warranty are met. If during this time a leak occurs and BTC determines that this leak is the result of a defect in workmanship or materials, BTC, will replace the heat exchanger. If the

Water Heater is installed in other than a single family dwelling, the heat exchanger warranty is limited to two (2) years from date of original installation.

OTHER WATER HEATER PARTS

If any other part fails within two (2) years after original installation, BTC will furnish a replacement part fee of charge.

The Water Heater may be delivered with components not manufactured by BTC ("Other Components). Other

Components are warranted by their manufacturer. BTC also will warrant the Other Components to be free from defects in workmanship and material for one year from the date of installation, provided they are installed and properly maintained by a qualified heating contractor and the other conditions of this warranty are met. If a defect exists in the

Other Components, BTC will repair or replace them, if BTC determines that a defect in workmanship or materials exists.

SERVICE LABOR COSTS

This warranty provides labor costs, at BTC approved rates, for one (1) year from the date of original installation, provided it is installed and properly maintained by a qualified heating contractor and the other conditions of this warranty are met.

ITEMS NOT COVERED

This limited warranty does not cover the following circumstances:

1. Components or parts not provided by BTC.

2. Serviceable items and normal maintenance as required per the Installation Manual.

3. The workmanship of any installer. BTC disclaims and does not assume any liability of any nature for unsatisfactory performance caused by improper installation, repair or maintenance.

4. Any labor or material costs for removal, reinstallation, repair and replacement of the defective component or part unless otherwise provided above.

5. Transportation to BTC, if necessary.

6. Damage caused by operation of the Water Heater in a corrosive atmosphere, scale depots and/or highly mineralized or unsoftened water supply, electrical failures, flooding, or acts of God.

7. Any Water Heater that has a failure of malfunction resulting from operation with either the flame sensor rod or overheat sensor removed.

8. Damage caused by any attachment or modification to the

Water Heater, including any energy-saving device.

9. Damage caused by operation of the Water Heater at water temperatures exceeding the maximum rating, or if the water is not supplied with potable water.

10. Shipping charges, delivery expenses or administrative fees incurred by the purchaser in repairing or replacing the Water

Heater.

CONDITIONS OF WARRANTY

The warranty herein is void under the following circumstances:

1. Failure or malfunction resulting from improper or negligent operation, accident, abuse, freezing, misuse, unauthorized alteration or improper installation, repair or maintenance. See the Owner's Manual for installation and maintenance information.

2. Any Water Heater that is operated without a flame sensor rod or overheat sensor.

3. Any Water Heater that is used or operated in a corrosive atmosphere or at water temperatures exceeding the maximum rating, or if the Water Heater is not supplied with potable water.

4. Work performed without prior authorization or approval and without authorization/requisition number and without proper documentation verifying compliance with above terms.

LIMITED WARRANTY

OTHER THAN THE OBLIGATIONS OF BTC EXPRESSLY SET

FORTH HERIN, BTC DISCLAIMS ALL WARRANTIES, EXPRESS

OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED

WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A

PARTICULAR PURPOSE. BTC'S SOLE OBLIGATION WITH

RESPECT TO THE WATER HEATER AND PURCHASER'S

EXCLUSIVE REMEDIES ARE SET FORTH IN THE FOREGOING

6 720 644 947 (2014/11) 520 PN

LIFETIME LIMITED WARRANTY FOR BOSCH TANKLESS WATER HEATERS | 33

LIMITED WARRANTY. BTC SHALL NOT BE LIABLE FOR ANY

INDIRECT, PUNITIVE, INCIDENTAL, SPECIAL,

CONSEQUENTIAL OR SIMILAR DAMAGES INCLUDING,

WITHOUT LIMIITATION, INJURY OR DAMAGE TO PERSONS OR

PROPERTY OR DAMAGES FOR LOSS OF USE, LOST PROFITS,

INCONVENIENCE OR LOSS OF TIME.

NOTE THAT ANY REPAIRED OR REPLACED PRODUCT WILL BE

WARRANTED FOR ONLY THE UNEXPIRED TERM OF THE

ORIGINAL WARRANTY.

Some states do not allow the exclusion of limitation of damages, or limitations on how long an implied warranty lasts, so the above limitations and exclusions may not apply to you.

WARRANTY CLAIMS PROCESS

If you have a warranty claim you should notify the heating contractor who installed your water heater and ask that the contractor notify the distributor from whom the contractor purchased the Water heater. If this action is not possible or you don't receive a response, contact Bosch

Thermotechnology Corp., 50 Wentworth Avenue,

Londonderry, NH 03053. To process your claim, you will need a copy of your original invoice or other proof of purchase and documentation showing the original installation date and location. The alleged defective components or parts must be returned to BTC in accordance with BTC procedure then in force for handling goods returned for the purpose of inspection to determine cause of failure (contact BTC if you have questions regarding the return process). If BTC determines that the returned components and/or parts are defective and that this warranty applies, BTC will furnish the repaired or replacement components and/or parts to an authorized BTC distributor who, in turn, will forward the components and/or parts to the heating contractor who installed your Water

Heater.

520 PN 6 720 644 947 (2014/11)

34 | Installer Checklist to be completed by installer upon installation

11 Installer Checklist to be completed by installer upon installation

Serial Number

(8 digit serial number is located on rating plate on right side panel)

Gas Pressure Reading

1)

___ ___ ___ ___ ___ ___ ___ ___

Static

Operating

Water Pressure

Building Water Pressure

Range if on Well system

Installing Company

Installer name

Address

Phone

Table 14

1) See Chapter 4.8 and gas pressure table (to be filled out by

installer)

Installation manual should be left with the owner after the installation is tested and completed.

6 720 644 947 (2014/11) 520 PN

Notes

| 35

520 PN 6 720 644 947 (2014/11)

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