Bosch Buderus SB625WS, Buderus SB745WS Installation Instructions Manual

Read these instructions carefully before installation and operation of the heating system.

Installation Instructions

Stainless Steel Condensing Boiler

Buderus SB625WS/Buderus SB745WS

6 720 805 220-00.1T

DANGER!

The installation instructions included in this Manual are intended solely for

use by a trained and certified installer, service company or the gas supply company. If the information in this manual is not followed, a fire or explosion may result causing property damage, personal injury, or death.

Have installation and service performed by a trained and certified

installer or service company, or the gas supply company.

Bosch recommends signing a service and maintenance contract with a

trained and certified installer or service company that covers annual servicing and condition-based maintenance. Proper maintenance is a fundamental requirement for safe and efficient operation and long service life.



The boiler must be serviced annually including the main burner, ignition

burner, the entire venting system, and the combustion air supply. All parts that show any signs of damage or corrosion must be replaced.

Improper installation, adjustment, alteration, service, or maintenance

can cause property damage, personal injury, or death. Refer to this manual and consult a trained and certified installer or service company, or the gas supply company before installation, service or maintenance.



The owner and operator is responsible for the operational safety and

regulatory compliance of the heating system.

THIS MANUAL SHOULD BE HANDED TO THE OWNER AND OPERATOR OF THE APPLIANCE.

INSTALLER MUST REVIEW ALL SAFETY INSTRUCTIONS WITH THE OWNER AND OPERATOR.

UPON COMPLETION OF THE INSTALLATION THE INSTALLER MUST INSTRUCT THE OWNER AND OPERATOR ON THE FUNCTIONALITY AND THE PROPER OPERATION OF THE BOILER AND THE HEATING SYSTEM

Low temperature condensing boilers for gas/oil fired power burners

6 720 805 218 (2013/02) en-us

2 | Contents

SB625WS/SB745WS6 720 805 218 (2013/02)

Contents

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

1.1 Explanation of symbols . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2 General safety instructions . . . . . . . . . . . . . . . . . . . . . . . 3

2 Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.1 Intended use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.2 Certification and testing mark . . . . . . . . . . . . . . . . . . . . . 6

2.3 Regulations and Guidelines . . . . . . . . . . . . . . . . . . . . . . . 6

2.3.1 National regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.3.2 Compliance with standards and regulations . . . . . . . . . . 6

2.3.3 Additional regulations for installations in the

Commonwealth of Massachusetts . . . . . . . . . . . . . . . . . 6

2.4 Suitable fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.5 Scope of delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.6 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.7 Tools, materials and auxiliary equipment . . . . . . . . . . . . 8

2.8 Data plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.9 Dimensions and specifications . . . . . . . . . . . . . . . . . . . . 9

2.9.1 Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.9.2 Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.9.3 Water connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3 Water treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.1 Chemical and physical characteristics . . . . . . . . . . . . . 13

3.2 Central heating system . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.2.1 Limescale deposits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.2.2 Deposit corrosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.2.3 Stray current corrosion . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.2.4 Diffused and localized acid corrosion . . . . . . . . . . . . . . 14

3.3 New central heating systems . . . . . . . . . . . . . . . . . . . . . 14

3.4 Reconditioning old heating systems . . . . . . . . . . . . . . . 14

3.5 Elimination air and gas from central heating system . . 14

3.6 Use of Antifreeze . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4 Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

5 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

5.1 Boiler Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

5.2 Assembling the paneling . . . . . . . . . . . . . . . . . . . . . . . . 18

5.3 Refitting the door hinges . . . . . . . . . . . . . . . . . . . . . . . . 20

5.3.1 Changing the direction of door opening . . . . . . . . . . . . 20

5.3.2 Removing the hinge assembly “B” . . . . . . . . . . . . . . . . . 23

5.4 Burners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

5.5 Combustion gas exhaust . . . . . . . . . . . . . . . . . . . . . . . . 24

5.6 Venting Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . 25

5.7 Code Required Vent Terminations . . . . . . . . . . . . . . . . 25

5.8 Combustion Air from outside the building . . . . . . . . . . 25

5.9 Combustion Air from an adjacent room . . . . . . . . . . . . 26

5.10 Condensate Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

5.11 Condensate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

5.11.1 Draining the condensate . . . . . . . . . . . . . . . . . . . . . . . . 26

5.11.2 Neutralizing the condensate . . . . . . . . . . . . . . . . . . . . . 26

6 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

6.1 Control unit settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

6.2 Hydraulic connection to the heating system . . . . . . . . 29

6.3 Hydraulic flow through boiler . . . . . . . . . . . . . . . . . . . . 29

6.4 Making the electrical connection . . . . . . . . . . . . . . . . . 30

6.5 Fitting temperature sensors . . . . . . . . . . . . . . . . . . . . . 31

6.6 Flushing the heating system . . . . . . . . . . . . . . . . . . . . . 31

6.7 Filling the heating system . . . . . . . . . . . . . . . . . . . . . . . 32

6.8 Preparing the heating system for operation . . . . . . . . . 32

6.9 Commissioning the control unit and burner . . . . . . . . . 32

6.10 Setting control unit parameters . . . . . . . . . . . . . . . . . . 32

6.11 Commissioning report . . . . . . . . . . . . . . . . . . . . . . . . . . 33

7 Shutting down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

7.1 Shutting down the heating system . . . . . . . . . . . . . . . . 34

7.2 Shutting down the heating system in an emergency . . 34

8 Inspection and maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . 35

8.1 Why is regular maintenance important? . . . . . . . . . . . . 35

8.2 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

8.2.1 Opening the door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

8.2.2 Adjusting the door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

8.3 Cleaning the boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

8.4 Checking and correcting the water pressure . . . . . . . . 37

8.4.1 When should you check the water pressure in the

heating system? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

8.4.2 Sealed unvented systems . . . . . . . . . . . . . . . . . . . . . . . 37

8.5 Inspection and maintenance reports . . . . . . . . . . . . . . 38

9 Spare parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

10 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

11 Environmental protection/disposal . . . . . . . . . . . . . . . . . . . . 48

12 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Key to symbols and safety instructions | 3

6 720 805 218 (2013/02)SB625WS/SB745WS

1 Key to symbols and safety instructions

1.1 Explanation of symbols

Warnings

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:

• NOTE indicates that property damage may occur.

• CAUTION indicates that personal injury may occur.

• WARNING indicates that severe personal injury may occur.

• DANGER indicates that severe personal injury or death may occur.

Important information

Additional symbols

1.2 General safety instructions

If you hear gas leaking

▶ Leave the building immediately. ▶ Prevent others from entering the building. ▶ Notify the police and fire department from outside the building. ▶ From outside the building, call the gas supply company and a trained

and certified installer or service company.

If you smell gas

▶ Turn off the gas shut-off valve. ▶ Open windows and doors ▶ 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 that they need to leave the building. ▶ Do not ring doorbells! ▶ Notify the police and fire department from outside the building. ▶ From outside the building, call the gas supply company and a trained

and certified installer or service company.

If you smell flue gas

▶ Switch off the heating system by shutting off the emergency shut-off

switch. ▶ Open windows and doors. ▶ Call a trained and certified installer or service company.

DANGER: Risk of fatal injury from failing to consider your own safety!

▶ Never risk your own life. Your own safety must always take the highest

priority

NOTICE: Risk of appliance damage from improper operation of the boiler!

▶ Only use the boiler for its intended purpose. ▶ Only operate the boiler if it has been installed and maintained per the

instructions provided in the Installation Manual. ▶ Do not attempt to operate an appliance if any part of it is not in

working order or is damaged. ▶ Use only original spare parts! The use of parts not supplied by the

manufacturer may cause damage to the boiler, other property and

personal injury. Also, boiler damage caused by the use of

unauthorized parts is not covered by the warranty.

DANGER: Risk of fire when soldering and brazing!

▶ Take appropriate protective measures when soldering and brazing

around combustible and flammable material.

NOTICE:

▶ The installation must comply with all applicable national, state, and

local codes, rules, and regulations. ▶ The operator is responsible for the operational safety and regulatory

compliance of the heating system. ▶ In the Commonwealth of Massachusetts, the appliance must be

installed by a licensed plumber or gas fitter.

DANGER: Risk of personal injury or death from flue gas poisoning!

▶ Do not install a thermostatic flue gas damper downstream of the draft

hood. ▶ Do not tamper with, remove, or attempt to repair the blocked vent

switch. ▶ When replacing the blocked vent switch, install the new part in the

original location. ▶ A blocked vent switch tripping more than once indicates a problem

with the venting system or chimney which must be repaired

immediately. ▶ Ensure none of the vent pipes and chimneys are damaged or blocked. ▶ Connect only one appliance to each venting system or chimney. ▶ The venting system must not feed into or route through another air

extraction duct. ▶ The venting system must be inspected annually. All parts that show

any signs of damage or corrosion must be replaced. ▶ Never close off or reduce the size of the combustion air openings. ▶ The boiler must not be operated until any obstructions have been

removed.

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

Important information for the proper use of the boiler is also provided in this manual. You will find the information with a symbol shown on the left and bordered by horizontal lines above and below the text.

Symbol Meaning

▶ Sequence of steps  Cross-reference to other points in this document or to

other documents

• Listing/list entry – Listing/list entry (2nd level)

Table 1

4 | Key to symbols and safety instructions

SB625WS/SB745WS6 720 805 218 (2013/02)

DANGER: Risk of personal injury or death from explosion!

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

certified installer or service company.

▶ Appliance installation, the connection of gas and vent piping, initial

commissioning, electrical connections, and service and maintenance must only be carried out by a trained and certified installer or service company.

DANGER: Risk of personal injury or death from fire!

▶ Do not use flammable or combustible material in the boiler room. ▶ It is recommended not to store any items within 16 inches (415mm)

of the appliance

CAUTION: Appliance damage from contaminated combustion air!

▶ Keep the combustion air free of corrosive substances, e.g.

halogenated hydrocarbons from painting operations or beauty salons.

▶ Keep combustion air free from dust and lint, e.g. from laundry or

agricultural operations.

▶ If clean room air is not available, fresh outdoor combustion air must be

provided

DANGER: Risk of personal injury or death from electric shock.

▶ Before removing the front panel, disconnect the heating system from

the electrical power supply by shutting off the emergency shutoff switch or the heating system circuit breaker.

▶ It is not enough to switch off the control panel. Power to the panel

must be disconnected! Ensure that the power is not restored unintentionally by following proper lock out/tag out procedures.

▶ Only qualified electricians are permitted to carry out electrical work.

DANGER: Safety devices!

▶ Never shut off safety valves! ▶ Hot water may escape from the safety valve at any time when the

appliance is running.

DANGER: Risk of personal injury or death after a flood!

▶ Do not attempt to operate an appliance if any part of it has been under

water.

▶ An appliance that was subject to flooding must be replaced.

NOTICE:

▶ Upon completion of the installation, these instructions should be

handed to the owner and operator of the appliance.

▶ The installer must instruct the owner and operator on the functionality

of the components and the proper operation of the boiler and the heating system.

▶ The boiler must be serviced annually including the main burner,

ignition burner, the entire venting system, and the combustion air supply. All parts that show any signs of damage or corrosion must be replaced.

Product Description | 5

6 720 805 218 (2013/02)SB625WS/SB745WS

2 Product Description

The high efficiency SB Series boilers are designed to condense flue gases through a unique three-pass construction for installation in a mechanical room. While they are designed primarily for central heating purposes, in conjunction with a suitable storage tank they can also be used to produce domestic hot water.

All parts that come into contact with the combustion gases are made from titanium stabilized stainless steel to ensure maximum resistance to the corrosive action of acid condensation.

The boiler has been designed with the combustion chamber at the top and the smooth pipe tube bundle at the bottom to optimize heat exchange and to maximize the condensing effect.

The boiler has a high total water content which is differentially distributed between its top and bottom sections. This hydraulic feature allows outgoing water to reach the set temperature quickly while

maintaining the condensing effect and the water heating time around the tube bundle for as long as possible.

The boilers feature lightly pressurized combustion chambers for a smoother burner action, and high temperature resistant, stainless steel turbulators inside the tube bundle for maximum burner efficiency.

The boiler body is thoroughly insulated with a layer of high density glass wool.

The paint finished external paneling is also internally insulated with a layer of high density glass wool.

The boiler’s front door and the flue gas chamber can be opened completely to facilitate the inspection, maintenance and cleaning of internal parts and to speed up servicing in general.

The front door can open in either direction and can be opened without removing the burner. The door is factory fitted with hinges on the left, but these can be reversed if necessary to suit individual installations.

Fig. 1 Main components

[1] Paneling [2] Heating flow outlet [3] Safety device fitting

[4] Heating return (high temperature) [5] Heating return (low temperature)

[6] Instrument for bulb/probe socket [7] Combustion chamber

[8] Flue connection [9] Flue gas box [10] Inspection port [11] Condensate drain [12] Boiler drain [13] Turbulators [14] Flue pipes [15] Second flue pass [16] Burner [17] Flame inspection window with pressure measurement point [18] Door

1 2 3 4 5

6 720 805 218-01.1T

1) On the 1550WS model the low temperature heating return is located at the rear of the boiler.

2) On the 745WS models (800-1550) the safety device fitting is flanged.

6 | Product Description

SB625WS/SB745WS6 720 805 218 (2013/02)

2.1 Intended use

This boiler must only be used for the purpose specified by the manufacturer and for which it is designed.

The SB625WS/SB745WS can be operated with gas, oil, and combination burners. For a list of the approved burners, please contact Bosch Thermotechnology Corp.

The boiler can be operated with an aquastat, the Logamatic 4000, and other control systems.

The manufacturer declines all responsibility, contractual or other, for damage to property or injury to persons or animals caused by improper installation, adjustment, maintenance or use.

2.2 Certification and testing mark

This appliance has been tested and certified and meets all applicable standards for the US and Canadian markets:

• CSA-AM 3.1 Industrial and commercial gas-fired package boilers

• CSA B140.0 General requirements for oil burning equipment

• CSA B140.2.1-10 Atomizing-type oil burners

• CSA B140.7-05 Oil-burning equipment - steam and hot water boilers

• UL 296 Standard for oil burners

• UL 726 Standard for oil-fired boiler assemblies

• UL 795 Standard for commercial industrial gas heating equipment

2.3 Regulations and Guidelines

2.3.1 National regulation

The heating system must comply with the requirements of the relevant regulatory authorities or otherwise of the National Fuel Gas Code, ANSI Z 223.1 In Canada, the requirements of CAN/CGA-B.149.1 and 2, or CAN/CGA-B.139 must be observed.

If specified by the relevant regulatory authorities, the heating system must comply with the regulations of the Standard for Controls and Safety Devices for Automatically Fired Boilers, ANSI/ASME CSD-1.

Carbon monoxide detectors must be installed as specified by the local regulations. The boiler must be serviced annually.

2.3.2 Compliance with standards and regulations

Installation of the boiler must comply with all applicable codes and regulations imposed by the national, Federal or local authorities and bodies. If no specific requirements are defined, in the USA, the latest edition of the National Fuel Gas Code ANSI Z223.1/NFPA 54 must be complied with.

In Canada, installation must comply in all respects with the latest edition of the Natural Gas and Propane Installation Code, CAN/CGA-B. 149, the Installation Code for Oil Burning Equipment, CAN/CGA-B. 139 and the applicable local regulations and requirements for the appliance category. The relevant authorities and regulatory bodies must be informed before installation starts.

Where required by local regulations, the system must comply with the American Society of Mechanical Engineers Safety Code for Controls and Safety Devices for Automatically Fired Boilers (ASME CSD-1).

The local regulations regarding minimum pressure detectors and lowwater safety cutouts must be observed. Installation and operation must comply with the device manufacturer‘s technical documentation.

We recommend fitting an 80 mesh dirt filter externally to the boiler return to prevent contamination of the boiler by the water source.

Leak test

A leak test must be carried out. The testing pressure is based on the normal operating pressure of the heating system and should be 1.3 times that pressure, and in any case no less than 14 psi (1 bar).

Safety limits

2.3.3 Additional regulations for installations in the Commonwealth of Massachusetts

(a) For all side wall horizontally vented gas fueled equipment installed in

every dwelling, building or structure used in whole or in part for residential purposes, including those owned or operated by the Commonwealth and where the side wall exhaust vent termination is less than seven (7) feet above finished grade in the area of the venting, including but not limited to decks and porches, the following requirements shall be satisfied:

• INSTALLATION OF CARBON MONOXIDE DETECTORS. At the time of

installation of the side wall horizontal vented gas fueled equipment, the installing plumber or gasfitter shall observe that a hard wired carbon monoxide detector with an alarm and battery back-up is installed on the floor level where the gas equipment is to be installed. In addition, the installing plumber or gasfitter shall observe that a battery operated or hard wired carbon monoxide detector with an alarm is installed on each additional level of the dwelling, building or structure served by the side wall horizontal vented gas fueled equipment. It shall be the responsibility of the property owner to

WARNING: Risk of fatal Injury from explosion of flammable gases!

▶ Installation, connection of the fuel supply and flue

pipe, commissioning, connection of the electrical power supply, servicing and repair may only be carried out by an authorized heating engineer.

▶ Any work on gas-carrying components may only be

carried out by an authorized gas installer.

The details on the boiler rating plate are definitive and must be observed.

Safety limits

Maximum allowable temperature: 230 °F

(110 °C)

Maximum operating temperature 210 °F

(98.8 °C)

Permissible operating pressure: 80 psi

(5.5 bar)

Maximum cycle time for: Safety temperature limiter: 40 s Temperature control: 40 s

Table 2 Safety limits

Product Description | 7

6 720 805 218 (2013/02)SB625WS/SB745WS

secure the services of qualified licensed professionals for the installation of hard wired carbon monoxide detectors.

– In the event that the side wall horizontally vented gas fueled

equipment is installed in a crawl space or an attic, the hard wired carbon monoxide detector with alarm and battery back-up may be installed on the next adjacent floor level.

– In the event that the requirements of this subdivision cannot be met

at the time of completion of installation, the owner shall have a period of thirty (30) days to comply with the above requirements; provided, however, that during said thirty (30) day period, a battery operated carbon monoxide detector with an alarm shall be installed.

• APPROVED CARBON MONOXIDE DETECTORS. Each carbon monoxide detector as required in accordance with the above provisions shall comply with NPA 720 and be ANSI/UL 2034 listed and IAS certified.

• SIGNAGE. A metal or plastic identification plate shall be permanently mounted to the exterior of the building at a minimum height of eight (8) feet above grade directly in line with the exhaust vent terminal for the horizontally vented gas fueled heating appliance or equipment. The sign shall read, in print size no less than one-half (½) inch in size, “GAS VENT DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS”.

• INSPECTION. The state or local gas inspector of the side wall horizontally vented gas fueled equipment shall not approve the installation unless, upon inspections, the inspector observes carbon monoxide detectors and signage installed in accordance with the provisions of 248 CRM 5.08(2)(a) 1 through 4.

(b) EXEMPTIONS: The following equipment is exempt from 248 CRM

5.08(2)(a) 1 through 4:

• The equipment listed in Section 10 entitled “Equipment Not Required To Be Vented” in the most current edition of NFPA 54 as adopted by the board; and

• Product Approved side wall horizontally vented gas fueled equipment installed in a room or structure separate from the dwelling, building or structure used in whole or in part for residential purposes.

(c) MANUFACTURERS REQUIREMENTS - GAS EQUIPMENT VENTING SYSTEM REQUIRED. When the manufacturer of Product Approved side wall horizontally mounted gas equipment provides a venting system design or venting system components with the equipment, the instructions provided by the manufacturer for the installation of the equipment and venting shall include:

• Detailed instructions for the installation of the venting system or the venting system components; and

• A complete parts list for the venting system design or venting system.

(d) MANUFACTURERS REQUIREMENTS - GAS EQUIPMENT VENTING SYSTEM NOT PROVIDED. When the manufacturer of Product Approved side wall horizontally vented gas fueled equipment does not provide the parts for the venting of flue gases, but identifies “special venting systems”, the following requirements shall be satisfied by the manufacturer:

• The referenced “special venting systems” shall be included with the appliance or equipment installation instructions; and

• The “special venting systems” shall be Product Approved by the Board, and the instructions for that system shall include a parts list and detailed installation instructions.

(e) A copy of all instructions for all Product Approved side wall horizontally vented gas fueled equipment, all venting instructions, all parts lists for venting instructions, and/or venting design instructions

shall remain with the appliance or equipment at the completion of the installation.

2.4 Suitable fuels

Permissible fuels

• Natural gas from the public gas supply in accordance with national regulations with a total sulphur content < 15ppm.

• LP in accordance with national regulations with a content of elementary sulphur < 1.5 ppm and volatile sulphur < 50 ppm.

• Ultra Low Sulphur Diesel in accordance with national regulations with a content of elementary sulphur < 15 ppm (for use as back-up fuel in condensing operation).

• Heating oil type 2 when boiler return temperature is not lower than 140 degrees Fahrenheit; non-condensing operation (for use as backup fuel only). See the warranty statement for additional details.

NOTICE:

▶ Do not use gasoline, crankcase drainings, or any oil

containing gasoline.

The boiler must only be operated with the specified fuels.

Only burners that are suitable for the specified fuels may be used.

Observe the manufacturer's burner selection list and the burner manufacturer's instructions.

8 | Product Description

SB625WS/SB745WS6 720 805 218 (2013/02)

2.5 Scope of delivery

The boilers SB625WS / SB745WS comes in two separate crates and one additional box.

Boiler body crate:

The boiler body crate bears the documentation envelope [1] and contains:

• Instruction manual

• Certificate of Warranty

• Bar code labels

• Ceramic insulation [2]

Fig. 2 Boiler body crate

Paneling crate:

The paneling crate, complete with assembly accessories, protected by cardboard packaging and a wooden crate.

Fig. 3 Paneling crate

Accessory box:

The boiler accessory box contains

• Manifold

• Pressure relief valve

• Pressure/temperature gauge

Checking the delivery for completeness

▶ After delivery, check all packaging is in perfect condition. ▶ Check the delivery for completeness. ▶ Dispose of packaging in an environmentally responsible manner.

2.6 Accessories

Control panels

The control panels listed below may be supplied by the manufacturer for use with the SB625WS / SB745WS boilers.

2.7 Tools, materials and auxiliary equipment

For the installation and maintenance of the boiler, standard tools are required, as used for heating, gas, water and electrical installations.

2.8 Data plate

Serial number plate

The serial number plate is located on the rear of the boiler block and specifies the serial number and model.

Data plate

This lists the appliance’s technical specifications and performance. The data plate will be factory installed on the boiler side panel.

The instruction manual is an integral part of the boiler. Once located, read it thoroughly and keep it safe.

6 720 805 218-11.2T

6 720 805 218-12.1T

Model Description

The Logamatic 4321 control unit is designed for low temperature and condensing operation in single or multiple boiler systems. Additional possible functions include DHW, mixed heating zones and solar thermal integration.

Table 3 Control panels

If you contact the manufacturer with any questions about this product, always provide the details on the data plate and serial number plate. These details enable us to assist you specifically and quickly.

If these plates or any other means of clearly identifying the product are defaced, removed or lost, proper installation and servicing may be difficult.

Product Description | 9

6 720 805 218 (2013/02)SB625WS/SB745WS

2.9 Dimensions and specifications

2.9.1 Dimensions

Fig. 4 Dimensions

Values obtained with RS.../M-burners.

AL1 E

6 720 805 218-13.1T

Description Unit SB625WS SB745WS

160 220 290 370 480 640 800 1050 1300 1550

A: Base width inch

(mm)

27 3/16 (690)

29 1/2 (750)

31 1/8 (790)

37 7/16 (950)

42 1/8 (1070)

44 1/2 (1130)

B: Overall width inch

(mm)

29 1/8 (740)

33 1/2 (850)

35 7/16 (900)

41 3/4 (1060)

46 7/16 (1180)

48 1/4 (1225)

C: Length base to front

inch (mm)

4 3/4 (120)

D: Height of burner plate

inch (mm)

36 7/16 (925)

40 9/16 (1030)

48 5/8 (1235)

54 3/4 (1390)

58 7/8 (1495)

62 5/8 (1590)

E: Length base to rear

inch (mm)

1 9/16 (40)

F: Flue connection depth

inch (mm)

2 3/4 (70)

H – Height o f water fittings

inch (mm)

52 3/4 (1340)

57 1/16 (1450)

66 3/4 (1695)

75 (1905)

80 5/16 (2040)

85 13/16 (2180)

H1 – Boiler height inch

(mm)

52 3/16 (1325)

56 9/16 (1435)

66 1/8 (1680)

74 7/16 (1890)

79 3/4 (2025)

85 1/4 (2165)

L – Length inch

(mm)

57 5/16 (1455)

64 3/16 (1630)

72 1/16 (1830)

80 1/8 (2035)88(2235)

100 3/4 (2560)

110 5/8 (2810)

118 1/2 (3010)

121 1/4 (3080)

L1 – Base length inch

(mm)60(1295)60(1295)

57 7/8 (1470)

65 3/4 (1670)

73 13/16 (1875)

81 11/16 (2075)

94 1/2 (2400)

104 5/16 (2650)

112 3/16 (2850)

Weight of boiler lbs

(kg)

1122 (510)

1168 (530)

1492 (677)

1660 (753)

2414 (1095)

2755 (1250)

4122 (1870)

4596 (2085)

5544 (2515)

6724 (3050)

Weight of paneling lbs

(kg)

110 (50)

132 (60)

154 (70)

198 (90)

264 (120)

308 (140)

352 (160)

473 (215)

506 (230)

Table 4 Technical Data

10 | Product Description

SB625WS/SB745WS6 720 805 218 (2013/02)

2.9.2 Technical Data

Description SB625WS SB745WS

160 220 290 370 480 640 800 1050 1300 1550

Fuel Gas Gas Gas Gas Gas Gas Gas Gas Gas Gas Rated input (Nat. Gas) MBH

(kW)

563 (164.9)

788 (230.9)

1014 (297.1)

1314 (385.0)

1689 (494.9)

2200 (644.7)

3003 (880.0)

3754 (1100.0)

4692 (1375.0)

5443 (1595.0)

Rated input (#2 Oil) GPH

(LPH)

4.0 (15.1)

5.6 (21.2)

7.2 (27.3)

9.3 (35.2)

12.0 (45.4)

15.7 (59.4)

21.4 (81.0)

26.8 (101.4)

33.5 (126.8)

38.8 (146.9)

Gross output MBH

(kW)

544 (159.7)

762 (223.6)

990 (290.2)

1280 (375.2)

1642 (481.5)

2190 (642.0)

2738 (802.4)

3650 (1070.0)

4563 (1337.4)

5293 (1551.4)

Sensible losses from stack

% 1.7 1.7 1.5 1.5 1.9 1.9 1.9 1.9 1.9 1.9

Jacket losses with burner mounted

% 0.3 0.3 0.5 0.6 0.6 0.6 0.6 0.6 0.6 0.6

Flue gas temperature (T)

°F

(°C)

< 113 - 167

(< 45 - 75)

< 113 - 167

(< 45 - 75)

< 113 - 167

(< 45 - 75)

< 113 - 167

(< 45 - 75)

< 113 - 167

(< 45 - 75)

Flue gas mass flow rate1lbs/sec

(kg/ sec)

0.15 (0.07)

0.19 (0.09)

0.26 (0.12)

0.33 (0.15)

0.44 (0.20)

0.57 (0.26)

0.72 (0.33)

0.94 (0.43)

1.19 (0.54)

1.38 (0.63)

Fireside pressure drop2Inch

W.C (mbar)

0.802 (2.0)

1.083 (2.7)

1.284 (3.2)

1.846 (4.6)

2.007 (5.0)

2.208 (5.5)

2.288 (5.7)

2.529 (6.3)

2.729 (6.8)

2.970 (7.4)

Firebox volume Ft3

(dm3)

6.07 (172)

8.51 (241)

9.85 (279)

15.61 (442)

17.51 (496)

26.59 (753)

30.15 (854)

36.62 (1037)

44.10 (1249)

Total volume of flue gas side

Ft3 (dm3)

8.93 (253)

9.78 (277)

14.58 (413)

17.02 (482)

26.03 (737)

30.37 (860)

45.55 (1290)

51.34 (1454)

62.25 (1763)

74.05 (2097)

Heat exchanger surface area

Ft2 (m2)

65.65 (6.1)

94.72 (8.8)

139.93 (13.0)

175.45 (16.3)

234.65 (21.8)

310.00 (28.8)

426.25 (39.6)

500.52 (46.5)

604.93 (56.2)

670.37 (62.2)

Specific heat load MBH/

ft2 (kw/ m2)

8.28 (26.18)

8.04 (25.40)

7.07 (22.32)

7.29 (23.01)

6.99 (22.08)

7.06 (22.29)

6.42 (20.26)

7.29 (23.01)

7.54 (23.79)

7.89 (24.94)

Maximum condensate production

Gal/h (l/h)

4.86 (18.4)

7.23 (27.4)

8.42 (31.9)

10.80 (40.9)

13.78 (52.2)

19.49 (73.8)

23.24 (88.0)

29.42 (111.4)

35.05 (132.7)

42.13 (159.5)

Maximum working pressure

PSI (bar)80(5.5)

80 (5.5)80(5.5)

80 (5.5)

80 (5.5)80(5.5)80(5.5)

80 (5.5)

Maximum admissible temperature

°F

(°C)

230 (110)

Maximum working temperature

°F

(°C)

210 (98.8)

Pressure drop T 50 °F (10 °C)

Ft. Hd. (mbar)

5.0 (150.1)

3.3 (100.4)

4.1 (121.5)

4.3 (128.7)

1.0 (30.2)

1.1 (33.8)

1.5 (46.4)

1.8 (54.0)

1.2 (36.0)

1.4 (43.2)

Pressure drop T 68 °F (20 °C)

Ft. Hd. (mbar)

1.2 (36.3)

0.9 (28.4)

1.0 (30.6)

0.9 (28.7)

0.3 (8.5)

0.3 (9.0)

0.4 (13.4)

0.5 (16.3)

0.3 (10.2)

0.4 (11.3)

Water capacity Gal

(l)

85.3 (323)

95.1 (360)

130.7 (495)

146.6 (555)

196.2 (743)

203.4 (770)

348.7 (1320)

368.5 (1395)

482.1 (1825)

501.9 (1900)

Table 5 Technical Data

1. Depends on return temperature 86-140 °F (30-60 °C)

2. At maximum output with water temps supply/return of 176/140 °F (80/60 °C) and CO2 = 9.7 %

Product Description | 11

6 720 805 218 (2013/02)SB625WS/SB745WS

2.9.3 Water connections

The boilers are designed and made for use in central heating installations, but can also be used for domestic hot water production if

connected to suitable sub-systems. Water fittings are as specified in the following table.

Fig. 5 Water connections - SB625WS/160-640 and SB745/800-1300

Fig. 6 Water connections - SB745WS/1550

EDC

2 3/4” (70 mm)

6 720 805 218-18.1T

EDC

6 720 805 218-19.1T

The choice of system components and the method of their installation are left up to the installer. Installers must use their expertise to ensure proper installation and functioning in compliance with all applicable codes.

12 | Product Description

SB625WS/SB745WS6 720 805 218 (2013/02)

Description SB625WS SB745WS

160 220 290 370 480 640 800 1050 1300 1550

1 – Heating supply inch

(DN)

2 1/2 (65)

3 (80)

4 (100)4(100)5(125)5(125)6(150)6(150)

2 – Heating return 1 (Low Temperature)

inch (DN)

2 1/2 (65)

3 (80)

4 (100)4(100)5(125)5(125)6(150)6(150)

3 – Heating return 2 (High Temperature)

inch (DN)2(50)

2 (50)

2 1/2 (65)

3 (80)

4 (100)4(100)

4 – Safety device fitting

Ø- inch 1 1/4 1 1/4 1 1/4 1 1/4 1 1/2 1 1/2 3333

5 – Boiler drain fitting Ø - inch 1111111 1/4 1 1/4 1 1/4 1 1/4 6 – Condensate drain

fitting

Ø- inch 11111 1/4 1 1/4 1 1/4 1 1/4 1 1/4 1 1/4

7 – Flue gas exhaust fitting

Ømm 200 200 250 250 300 300 350 350 400 450

8– Instrument bulb/ probe sockets

n° x Ø ‘’ 3 x 1/2 3 x 1/2 3 x 1/2 3 x 1/2 3 x 1/2 3 x 1/2 3 x 1/2 3 x 1/2 3 x 1/2 3 x 1/2

A– Distance from burner head to heating supply

inch (mm)

11 7/8 (302)

11 13/16 (300)

12 5/8 (321)

12 1/4 (311)

16 1/8 (410)

17 5/16 (440)

17 3/8 (442)

B– Distance from heating flow outlet to return 1

inch (mm)

34 7/8 (885)

41 3/8 (1050)

48 5/16 (1235)

55 5/16 (1405)

63 3/16 (1605)

70 7/8 (1800)

80 11/16 (2050)

86 5/8 (2200)

101 3/4 (2582)

C – Distance between heating returns 1 & 2

inch (mm)

7 7/8 (200)

11 13/16 (300)

9 7/8 (250)

10 1/8 (255)

11 13/16 (300)

13 13/16 (350)

28 13/16 (732)

D – Distance between heating return 2 and safety device fitting

inch (mm)

11 1/4 (285)

11 13/16 (300)

17 3/4 (450)

23 5/8 (600)

27 9/16 (700)

29 1/2 (750)

33 1/2 (850)

E – Distance between heating flow outlet and safety device fitting

inch (mm)

15 3/4 (400)

17 3/4 (450)

21 1/16 (535)

21 11/16 (550)

23 13/16 (605)

27 9/16 (700)

33 1/2 (850)

39 3/8 (1000)

F – Distance between heating return 1 and flue gas outlet

inch (mm)

10 5/8 (270)

12 13/16 (325)

13 5/8 (345)

22 1/4 (565)

G – Height of condensate drain

inch (mm)

6 5/16 (160)

6 1/2 (165)

8 1/2 (215)

7 11/16 (195)

8 7/8 (225)

9 1/4 (235)

H – Height of boiler flanges

inch (mm)

52 3/4 (1340)

57 1/16 (1450)

66 3/4 (1695)

66 3/4 (1695)75(1905)75(1905)

80 5/16 (2040)

85 13/16 (2180)

I – Height of flue gas outlet

inch (mm)

20 1/4 (515)

21 1/2 (545)

25 3/8 (645)

26 3/4 (680)

28 3/8 (720)

31 11/16 (805)

L – Height of boiler drain fitting

inch (mm)

2 3/8 (60)

2 7/16 (61)

3 1/4 (82)

3 3/8 (86)

3 1/2 (90)

3 3/8 (86)

M – Boiler centerline inch

(mm)

13 9/16 (345)

14 9/16 (375)

15 9/16 (395)

19 5/16 (490)

21 1/16 (535)

22 1/4 (565)

N– Distance from burner head to door

inch (mm)

4 5/16 (110)

4 3/4 (120)

4 15/16 (125)

5 1/2 (140)6(150)

O – Distance from Boiler drain fitting

inch (mm)

5 3/16 (132)

5 3/8 (137)

4 15/16 (125)

6 7/8 (175)

7 1/8 (181)7(178)

P – Height of heating return 1 (Low Temperature)

inch (mm)

– – – – – – – – – 53 7/8

(1370)

Table 6 Technical Data

Water treatment | 13

6 720 805 218 (2013/02)SB625WS/SB745WS

3 Water treatment

The quality of the fill and top-up water is an essential factor for increased efficiency, functional reliability, long service life and for maintaining the constant operational condition of a heating system. If the system is filled with water that has a high calcium hardness, this will be deposited on the heat exchanger surfaces and will obstruct the transfer of heat to the heating water.

As a result, the wall temperatures of the stainless steel heat exchanger surfaces will increase and the thermal stress (loads on the boiler body) will increase. Water treatment is an essential factor in ensuring trouble free operation, availability, a long service life and the efficiency of the heating system.

3.1 Chemical and physical characteristics

The chemical and physical characteristics of heating system water must be similar to those of drinking water. A chemical water treatment device is recommended in order to protect system components as well as an inlet filter to prevent solid particles from entering the system in suspension and causing corrosion or sludge.

Typical layouts of water treatment systems

Fig. 7 Water treatment for heating installations

[1] Filter [2] Water softener [3] Boiler [4] Chemical treatment unit

Chemical and physical requirements of heating system water

3.2 Central heating system

Possible causes for corrosion and limescale

Typical problems encountered in central heating systems include:

• the breakage of heated surfaces through overheating caused by the thermal insulation of limescale deposits on the water side

• oxygen corrosion

• deposit corrosion

• stray current corrosion

• diffused and localized acid corrosion.

3.2.1 Limescale deposits

Limescale forms when the calcium and magnesium bicarbonates that are dissolved in the water at ambient temperature become chemically transformed when the water is heated. Calcium bicarbonate forms calcium carbonate, water and carbon dioxide, while magnesium bicarbonate transforms into magnesium hydroxide and carbon dioxide.

Calcium bicarbonate Ca(HCO

3)2

when temperature is increased:

Form. 1 Calcium bicarbonate changes when temperature is increased

Magnesium bicarbonate Mg(HCO3)

when temperature is increased:

Form. 2 Magnesium bicarbonate changes when temperature is

increased

Calcium carbonate and magnesium hydroxide precipitate to form insoluble deposits that adhere and compact on surfaces to form limescale, a substance with a high thermal insulating power. Inside a boiler, limescale forms mainly in areas subj ect to direct heat and high temperatures. It is so common to find deposits localized in a few

NOTICE:

If it proves impossible to treat the heating system water supply properly because the water charging system is automatic and uncontrolled, if there are no barriers installed to prevent water oxygenation, and if the heating system includes an open expansion vessel, then the boiler itself must be separated from the heating system by means of a heat exchanger.

Installation must conform to any and all national, fed eral, state and local standards and codes.

6 720 805 218-17.1T

32 4

Parameters Unit of measure Heating water

pH 7.5- 9,5 Hardness ppm <50 Electrical conductivity s/cm < 100 Chlorides mg/l <10 Sulphides mg/l <10 Nitrides mg/l <10 Oxygen in solution mg/l – Iron (Fe) mg/l <0.5

Table 7 Requirements of heating system water

NOTICE:

Chemical products used for water treatment must be compatible with applicable water pollution laws. Provided they are properly applied, these laws guarantee the safe functioning of the heating system.

CaCO3H2OCO

Mg OH22CO

14 | Water treatment

SB625WS/SB745WS6 720 805 218 (2013/02)

specific areas, where temperature is the highest. A coating of limescale of only 1 mm can cause severe overheating in metal parts and consequent damage through thermal stress. It is continuous topping up (automatic fill from incoming water) that causes thick deposits to form, leading to boiler breakdown.

3.2.2 Deposit corrosion

Deposit corrosion is an electro-chemical phenomenon caused by the presence of foreign bodies (sand, rust, etc.) in the water mass. These solid substances generally form deposits (sludge) in the bottom of the boiler. The lower parts of the boiler can therefore be affected by a chemical reaction of micro-corrosion caused by the electrochemical potential difference created between the metal (steel) and the impurities around it.

3.2.3 Stray current corrosion

Stray current corrosion is not common, but can be caused by the different electrical potentials of the boiler water and the metal body of the boiler or piping creating a cathode/anode effect.

All metal parts of the boiler should therefore be connected to an efficient ground (earth) point, even though this form of corrosion is actually caused by the passage of DC current, no longer used for domestic power. Stray current corrosion is easily identified by the regular tiny conical holes it leaves.

3.2.4 Diffused and localized acid corrosion

Other forms of corrosion exist that are harder to see but nonetheless dangerous because they affect the entire heating system and not just the boiler.

These forms of corrosion are generally due to the water becoming acidic (pH < 7), and are caused by:

• Incorrect water softening and the presence of carbon dioxide (which lowers the water’s pH). Carbon dioxide is released more easily in softened water and also forms during the limescale formation process. Acid corrosion is diffused and attacks the entire system more or less uniformly

• Incorrect acid washing (e.g. washing done without a passivating agent). Acid introduced into the system can cause localized perforation if it is not properly removed from all parts of the system. The formation of corrosion can easily be detected by analyzing the chemical composition of the water. Even a minimal iron content is a clear sign that corrosion is occurring.

3.3 New central heating systems

Mistakes to avoid and precautions.

To eliminate contact between system water and the air, the following is required:

• ensure that the expansion vessel is a closed vessel, and of the correct size and pre-charge pressure (the pressure should be checked periodically)

• ensure that the system is always kept at a pressure higher than atmospheric pressure at all points (including the pump suction side) and at all operating conditions (precisely because the seals, gaskets

and joints in a water circuit are designed to resist pressure from within, but not to resist a vacuum within)

• ensure that no part of the system is made from materials that are permeable to gases (e.g. plastic pipes with no oxygen barrier used in floor heating systems).

The heating system should not need any further topping up once it is filled and bled of all air. Any top-ups need to be monitored (by a meter), treated and recorded in the heating system’s technical log. The presence of a water softener in conjunction with an automatic filling system is not sufficient to ensure proper performance. If more than one boiler is installed in a large system, all boilers must be switched on at the same time to ensure that any possible limescale formation is uniformly distributed.

3.4 Reconditioning old heating systems

Frequent mistakes and necessary precautions.

If a boiler must be replaced, do not refill the entire central heating circuit if the quality of water in it conforms to requirements.

If the quality of water fails to conform to requirements, either recondition the old water or separate the water circuits (water in the boiler circuit must conform to requirements).

Conclusions

Never forget that proper water conditioning and proper heating system design not only guarantee safety and security but also ensures significant savings in maintenance costs and overall thermal efficiency.

3.5 Elimination air and gas from central heating system

When designing new heating systems, it is necessary to eliminate the air and other gases that form in the system.

Recently added fill or top-up water loses much of its volume in the first few days because it releases gases. With new systems you should therefore initially check the heating water pressure on a daily basis, and then at gradually longer intervals. Air and gas in the water system not only causes the corrosion problems listed above, but also reduces thermal efficiency, causing pump failure and noise and vibration throughout the heating system. Air bubbles and gas inevitably form in heating circuits during normal functioning, especially if the precautions listed above are not fully respected.

The technical details provided in this section refer specifically to domestic and industrial hot water heating systems with working temperatures up to 210 °F (98,8 °C).

NOTICE:

The original system filling water and any topping up water must always be filtered (using synthetic or metal mesh filters with a filtration rating of no less than 50 microns) to prevent sludge from forming and triggering deposit induced corrosion.

NOTICE:

Loss of water from the system, and the consequential need to add water, can be caused not only by leaks from the circuit, but also from the incorrect sizing of the expansion vessel or precharge pressure. (If normal thermal expansion causes pressure in the system to increase beyond the setting of the safety valve, that safety valve will open continuously.) The expansion vessel size should be corrected to prevent unnecessary safety valve blow-off.

Water treatment | 15

6 720 805 218 (2013/02)SB625WS/SB745WS

In particular:

• as temperature increases, oxygen becomes less watersoluble and bubbles begin to form.

• CO2 (carbon dioxide) is generated as the carbonates of calcium and magnesium precipitate out.

• the chemical oxidation of the metals in the system also generates hydrogen.

These gases must be eliminated as they are formed. The system needs to be designed and installed so that all gases can be vented quickly, easily, and effectively.

3.6 Use of Antifreeze

In areas where freezing may occur, an antifreeze may be added to the system water as protection. Please adhere to the specifications provided by the antifreeze manufacturer.

▶ Use the anti-freeze manufacturer’s data to determine the anti-freeze

ratio for the desired freeze protection temperature.

▶ Do not exceed 50% antifreeze mix ratio and do not use antifreeze

other than specifically made for hot water heating systems.

Do not use automotive silicate-based antifreeze in the heating system.

16 | Transport

SB625WS/SB745WS6 720 805 218 (2013/02)

4 Transport

▶ Only use lifting equipment of adequate capacity. ▶ Remove the transport straps and the wooden pallet before

positioning the boiler.

▶ For lifting using a rigging crane, use only the lifting provisions

supplied.

▶ When lifting the boiler using chains, make sure that at least two chains

are load-bearing. Lift up very carefully.

▶ Maintain less than a 45 degree angle with the vertical when lifting the

boiler with chains or cables.

▶ The rigging crane must be operated by trained personnel.

Fig. 8 Transport

WARNING: Risk of injury from carrying heavy loads and inadequately securing loads for transport. ▶ Use suitable means of transportation, e.g. several

pallet trucks, a forklift truck, crane or heavy duty rollers.

▶ Secure the load against falling.

Never pull retaining straps (fixing straps, chains) over the boiler insulation.

6 720 805 218-14.1T

+ 36 hidden pages

Bosch Buderus SB625WS, Buderus SB745WS Installation Instructions Manual

Specifications and Main Features

Frequently Asked Questions

User Manual