Bosch Buderus SB625WS User manual

Read these instructions carefully before installation and operation of the heating system.
Operating 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 inthis 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
6 720 805 220 (2013/02) US/CA

2| Contents
Stainless Steel Condensing Boiler - SB625WS / SB745WS6 720 805 220 (2012/10)
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 Correct use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Certification and testing mark . . . . . . . . . . . . . . . . . . . . . 5
2.3 Data plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.4 The correct fill and make-up water . . . . . . . . . . . . . . . . . 5
2.5 The correct fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.6 Combustion Air Quality . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3 System start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1 Making the system operational . . . . . . . . . . . . . . . . . . . . 7
3.2 Check and correct the operating pressure . . . . . . . . . . . 7
3.2.1 Checking the operating water pressure . . . . . . . . . . . . . 7
3.2.2 Filling with heating water and bleeding the system . . . . 7
3.3 Starting up the control panel and the burner . . . . . . . . . 7
4 Shutting down the system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.1 Switching off the control panel and the burner . . . . . . . 8
4.2 Shutting down the system in an emergency . . . . . . . . . . 8
5 System maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.1 Why is regular maintenance important? . . . . . . . . . . . . . 9
5.2 Ordinary analysis and checking, frequency and sampling
points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Key to symbols and safety instructions | 3
6 720 805 220 (2012/10)Stainless Steel Condensing Boiler - 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.
▶Donotsmoke!
▶ 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
Stainless Steel Condensing Boiler - SB625WS / SB745WS6 720 805 220 (2012/10)
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
6 720 805 220 (2012/10)Stainless Steel Condensing Boiler - SB625WS / SB745WS
2 Product description
The oil/gas fired boiler SB625WS/SB745WS has been developed and
built employing the latest technologies and safety regulations.
Particular emphasis is placed on ease of operation. Please observe the
safety instructions and the operating instructions to ensure optimum
safe, economical and environmentally-friendly operation of your
system.
The main components of the SB625WS/SB745WS gas/oil fired boiler
are:
• Boiler block [3].
The boiler block transfers the heat generated by the burner to the
heating water.
• Boiler shell [1], thermal insulation [2].
The boiler jacket and thermal insulation minimize energy loss.
Fig. 1 Oil/gas fired boiler Buderus SB625WS/Buderus SB745WS
[1] Boiler shell (jacket)
[2] Thermal insulation
[3] Boiler block
2.1 Correct use
The SB625WS/SB745WS is designed for heating boiler water and water
heating. Any other purpose is considered improper use. Any resulting
damage is excluded from the manufacturer's warranty.
The SB625WS/SB745WS can be operated with gas, oil, and
combination burners. For a list of the approved burners, please contact
Bosch Thermotechnology Corp. Required operating conditions of
allowable fuels may be found in the boiler installation manual.
The boiler can be operated with an aquastat, the Logamatic 4000, and
other control systems.
2.2 Certification and testing mark
This appliance has been tested and certified and meets all applicable
standards for the US and Canadian markets.
2.3 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.
2.4 The correct fill and make-up water
Note the fundamental system-specific water quality requirements.
Water designation
Water is used as the heat transfer medium in your heating system.
Depending on its purpose, the water is given different descriptions.
• Heating water:
Water contained within your heating system.
• Fill water:
Water used for the first filling of your system before commissioning.
• Make-up water:
Water used for topping up the heating system in case of water loss.
Water quality requirements
All water contains substances, e.g. Ca (HCO3)2 (calcium hydrogen
carbonate) that could affect the operation of your heating system. These
can cause corrosion, scale formation or deposits.
To ensure your heating system always operates economically, properly
and safely, not to mention in an energy-efficient manner, we require that
you regularly monitor the quality of the fill and make-up water and treat
it accordingly as and when necessary.
6 720 805 220-01.1T
1
2
3
If you contact the manufacturer with anyquestions 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.
NOTICE: System damage from corrosion or scale
formation as the result of using fill and make-up water
that does not conform to the system-specific
requirements.
▶ Ask your trained and certified installer or local water
company what the concentration of Ca (HCO3)2
(calcium hydrogencarbonate) is in your area.
▶ If the fill and make-up water does not meet system-
specific requirements, it will have to be treated.
Consult your trained and certified installer if this is the
case.

6| Product description
Stainless Steel Condensing Boiler - SB625WS / SB745WS6 720 805 220 (2012/10)
For the correct use and treatment of the fill and make-up water, the
contents of the following table MUST be observed.
2.5 The correct fuel
To ensure it operates properly, the heating system requires fuel of the
correct type and grade.
2.6 Combustion Air Quality
▶ Keep the supply of combustion air free of corrosive substances (e.g.
halogenated hydrocarbons that contain chlorine or fluorine
compounds).
This will help prevent corrosion.
▶ Never use or store chlorinated cleaning agents or halogenated
hydrocarbons (as contained in spray cans, solvents or cleaning
agents, paints and adhesives, for example) in the boiler room.
▶ Keep the combustion air supply free of dust.
▶ If building work is taking place in the installation room and creating a
lot of dust, shut the boiler down.
▶ A burner contaminated during building work must be cleaned before
commissioning.
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 2 Requirements of heating system water
NOTICE: Risk of system damage from use of incorrect
fuel.
▶ Only use the fuel specified. The correct fuel is entered
in Tab. 3 by the heating contractor.
Consult your system installer if you intend on changing
the fuel for your system.
NOTICE: Risk due to oil leaks
▶ When using oil as the fuel, national regulations hold
the operator responsible for immediately calling a
specialist contractor to remedy oil leaks the moment
they are discovered.
Use the following fuel:
Stamp/Signature/Date
Table 3 Fuel to be used (entered by heating system installer)

System start-up | 7
6 720 805 220 (2012/10)Stainless Steel Condensing Boiler - SB625WS / SB745WS
3 System start-up
This chapter explains how you prepare the system for operation and how
to commission the control panel and the burner.
3.1 Making the system operational
You should check the following to prepare the system for operation:
▶ Operating water pressure of the system (Chapter 3.2).
▶ Fuel is supplied and the main fuel shut-off valve is open.
▶ Heating system emergency shutoff switch set to ON.
Ask your heating contractor to show you where the fill valve for your
heating system is located.
3.2 Check and correct the operating pressure
Your heating system must contain sufficient water to ensure the
functionality of your system.
If the operating pressure in the system is too low, fill make-up water into
your system (Chapter 2.4, page 5).
• Recently added fill or make-up water loses much of its volume in the
first few days because it releases gases. With newly filled heating
systems, initially check the operating pressure daily and then in ever
increasing intervals.
• Once fill or make-up water volume has stabilized, check the operating
pressure of the heating water once a month.
All factory default settings will have already been made by the heating
contractor when the system was first commissioned.
3.2.1 Checking the operating water pressure
The recommended operating pressure should remain above 22 psi
(1.5 bar) to eliminate air from the system and prevent system noise.
▶ Read the current operating pressure and temperature ( °F ( °C)) on
the temperature/pressure gauge.
▶ If the operating pressure drops below design, fill up the heating water.
Fig. 2 Pressure/temperature gauge
3.2.2 Filling with heating water and bleeding the system
▶ Slowly fill the heating system via the on-site fill valve. During filling,
observe the display (pressure gauge).
▶ Once the desired operating pressure is reached, stop the procedure.
▶ Bleed the heating system via the purge valves.
▶ Add fill water again if the operating pressure drops as a result of
bleeding the system.
3.3 Starting up the control panel and the burner
Start your boiler via the control panel (Fig. 3). By starting the control
panel, you also automatically start the burner. The burner is then fired by
the control panel. For further details, see the operating instructions of
the relevant control panel or burner.
▶ Switch the boiler water thermostat [1] to "AUT".
▶ Set the ON/OFF switch [2] to "I" (ON).
Fig. 3 Control panel (for example: Logamatic 4000)
[1] Boiler water thermostat
[2] ON/OFF switch
WARNING:
▶ Do not attempt to start the burner when excess heat
oil has accumulated, when the units is full of vapor, or
when the combustion chamber is very hot.
NOTICE: Risk of system damage due to frequent
refilling.
▶ If you need to add water frequently, the heating
system may be damaged by corrosion and scale
buildup depending on the water quality.
▶ Bleed the heating system. If necessary, fill with make-
up water.
▶ Check the heating system for leaks and the correct
operation of the expansion vessel.
▶ Notify your heating contractor if you find the need to
refill your heating system frequently.
Air pockets may form in the heating system from the fill
or make-up water releasing gases.
Let your local heating contractor show you where the
boiler fill and drain valve for filling and draining the
heating water is located on your heating system.
NOTICE:
The control unit should only be operated by a trained
professional - call your service personnel for servicing
advice.
Follow the control panel operating instructions.
7 747 019 141-17.1RS
2
1
6 720 642 624-03.1O

8| Shutting down the system
Stainless Steel Condensing Boiler - SB625WS / SB745WS6 720 805 220 (2012/10)
4 Shutting down the system
This chapter explains how you shut down your boiler and switch off the
control panel and the burner. Furthermore, it contains details on how to
shut down your heating system in an emergency.
▶ Shut off the fuel supply at the main fuel shut-off valve.
4.1 Switching off the control panel and the burner
Shut down your boiler via the control panel (Fig. 3). The burner is
automatically shut down when the control panel is switched off.
▶ Set the ON/OFF switch (Fig. 3, [2]) to "0" (OFF).
4.2 Shutting down the system in an emergency
In other dangerous situations, immediately close the main fuel shut-off
valve and the power supply of the heating system using the emergency
shutoff switch or by disengaging the heating system circuit breaker
(Chapter 1.2, page 3).
NOTICE: Risk of system damage from freezing.
▶ The system can freeze up if it is out of service, e.g.
from a shutdown because of fault(s).
▶ Protect your system against frost damage where
temperatures below freezing are expected.
▶ Drain the heating water at the lowest point in the
system, using the boiler drain valve. To do this, open
a purge valve at the highest point in the system.
Contact the Technical Assistance Service if you
encounter any problems in completing the following
procedure.
For further details on this subject, see the operating
instructions for the relevant control panel.
Only in emergencies, switch off the system using the
emergency shutoff switch or by disengaging the heating
system circuit breaker.

System maintenance | 9
6 720 805 220 (2012/10)Stainless Steel Condensing Boiler - SB625WS / SB745WS
5 System maintenance
This chapter explains, why regular maintenance is important for your
system. It will also indicate to you, how you can check and regulate the
water pressure.
Observe the separate maintenance instructions for maintenance work
on the neutralising system. Only specialists should carry out work on the
neutralising system.
5.1 Why is regular maintenance important?
You should have your system regularly serviced for the following
reasons:
• to maintain the highest level of efficiency and to operate the system
economically (low fuel consumption),
• to achieve a high level of operational reliability,
• to maintain the highest level of environmentally responsible
combustion.
5.2 Ordinary analysis and checking, frequency and
sampling points
The following symbols and terms are used to identify sampling
frequency and the location of sampling points:
CAUTION: System damage through inadequate
cleaning and maintenance.
▶ Have your system inspected, cleaned and maintained
annually by a specialist contractor.
▶ We recommend you enter into a contract covering an
annual inspection and maintenance on an "as-
required-basis".
Symbols and terms
Frequency of
analysis
A - Twice a year, in the season in which the heating
system is in use
B - Once a month
C - Once every 15 days
D - Once a week
Sampling points 1 - Filling water
2 - Filling and/or refilling water
3 - Water in the boiler or heating circuit
Table 4
Type of system
analysis and checks
Hotwaterheating
system
Notes
Appearance 2A-3A
pH 3A
Total hardness 2B
Fixed residues
Electrical conductivity Electrical conductivity
measurement can be
used instead
Iron 3A Fixed residue
measurement can be
used instead
P-alkalinity
Chemical conditioner 3A
Copper 3A
Table 5

10 | Troubleshooting
Stainless Steel Condensing Boiler - SB625WS / SB745WS6 720 805 220 (2012/10)
6 Troubleshooting
Heating system faults are shown on the control panel display. You will
find detailed information regarding fault displays in the service
instructions for the relevant control panel. The burner fault is also
indicated by a fault lamp on the burner.
▶ Press the burner reset button (see burner operating instructions).
If the burner does not restart after three attempts, refer to the technical
documentation provided with the burner to find out how to reset it.
NOTICE: Risk of system damage from freezing.
▶ The system can freeze if it is out of service, e.g. power
failure, shutdown caused by fault(s).
▶ If the system remains switched off for several days
because of a fault shutdown, you should drain the
heating water via the boiler drain valve at the lowest
point in the system to protect it against freezing.
NOTICE: Risk of system damage due to too many resets.
▶ The burner ignition transformer may be damaged if
you press the reset button more than three times in
succession when the burner refuses to start.
▶ Do not attempt to remedy the fault by pressing the
reset button more than three times in succession.

| 11
6 720 805 220 (2012/10)Stainless Steel Condensing Boiler - SB625WS / SB745WS
Notes