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In Massachusetts, this appliance must be installed by a licensed plumber or gas fitter. These instructions are available in English and French. Please keep these instructions for future reference. Gas Condensing Stainless Steel Boiler BUDERUS SSB BOILER SSB255 | SSB399 | SSB512 Installation and Service Instructions for Contractors...
► Immediately correct all faults to prevent system damage. ► Make sure that a licensed contractor / gas fitter installs the boiler, ► Only use original Bosch spare parts. Losses caused by the use of connects gas and vent, places the boiler in operation, connects the parts not supplied by Bosch are excluded from the Bosch warranty.
► The boiler is intended only for the use for which it was specifically • The gas-fired condensing SSB boilers are designed to be used in designed and built. Bosch is hereby excluded from any liability for central heating systems. Any other use is prohibited.
2 .4 Environmental responsibility / disposal Environmental responsibility is one of the fundamental company policies of the Bosch Group. We regard quality of performance, economy and environmental responsibility as equal objectives. Environmental protection laws and regulations are strictly adhered to.
20% input 30% input 100% input Return Water Temperature (°F) @ 36 Degree Rise Fig. 6 Thermal Efficiency Curves SSB255* * Thermal Efficiency curve is for reference only as this is a residential boiler 100% 20% input 30% input 100% input Return Water Temperature (°F) @ 36 Degree Rise...
Regulations | 13 installed on the next adjacent floor level. Regulations - In the event that the requirements of this subdivision can not 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; Observe all rules, regulations, standards and guidelines provided, however, that during said thirty (30) day period, a applicable to the installation and operation of this appliance...
14 | Installation The recommended clearance for ease of installation and service are Installation illustrated in the following picture: 4 .1 Packaging and product identification The SSB is delivered strapped to a pallet, packed and protected in a cardboard carton. NOTICE: The packaging shows the characteristics of the 2”...
To avoid any presence of oxygen in the system, it is advised to prevent as connection connection little as possible air during installation. Usual spots where air is most likely SSB255 1-1/2” NPT male 1-1/2” NPT male to seep in are: gaskets, pumps, air vents and O-rings gaskets. Using SSB399 1-1/2”...
The boiler is supplied with a pressure relief valve (PRV). The relief pressure for each valve for each model of the boiler is shown in the following table: Boiler model Relief Pressure SSB255 30 psi (2.07 bar) SSB399 30 psi (2.07 bar) SSB512 75 psi (5.17 bar)
SSB255 ∆ p / Feet of Head Flow rate / GPM Fig. 12 SSB255 Pressure drop It is important to ensure the pump has the correct flow rate for the system to avoid a low water circulation situation. In event of an inadequate flow rate, the safety devices of the boiler will automatically stop the burner.
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18 | Installation SSB399 ∆ p / Feet of Head Flow rate / GPM Fig. 13 SSB399 Pressure drop SSB512 ∆ p / Feet of Head Flow rate / GPM Fig. 14 SSB512 Pressure drop 6720818454 (2016/02) US...
Installation | 19 4 .4 .6 Condensate removal stream. The condensate water produced by the boiler during its normal operation • Never use copper pipes or of other material not intended for the is collected by two plastic pipes (A and B) provided with the boiler and specific purpose, because the action of condensate will cause a rapid connected with a plastic collector inside the case.
20 | Installation The general electrical connection is shown in the following diagram : (**) Boiler Pump CH Pump DHW CASCADE DHW Tank Room Supply 120 V Main in Alarm 120 V Aux Pump LINK Switch Door Sensor Thermostat Sensor 3 Way 1 2 3 4 5 6 7 8 9 10 11 12 13 14 101 102 103 104 105 106 107 108 109...
Installation | 21 4 .5 .5 Electrical wiring diagram SSB255 ONLY - SSB399 ONLY SSB512 ONLY LOW VOLTAGE HIGH VOLTAGE HIGH IN / OUT VOLTAGE PUMP CH PUMP DHW 120 V Supply MAIN PUMP CASCADE Room ALLARM 120 V AUX...
22 | Installation 4 .6 Gas supply piping LP conversion kit installation (SSB255) Natural Gas to LP conversion Verify that the type and the pressure of the gas supplied correspond with those required for the boiler. When field converting the boiler from Natural The heating unit is factory preset for operating with natural gas.
24 | Installation • Remodeling areas; instructions. • Garages with workshops. The exhaust vent and the combustion air inlet lines must be supported to prevent sagging per the vent manufacturer’s instructions. 4 .7 .1 General venting and combustion air piping system Do not mix components from different systems.
• The diameters of the flue outlet and combustion air intake inlet are designed to fit standard PP, PVC, CPVC and stainless steel pipes. The following table gives the diameter of the flue adapter on the boiler. Boiler SSB255 SSB399 SSB512 Diameters 3” - 80mm 4”...
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26 | Installation Fig. 28 Direct vent (sealed combustion) It is not recommended to terminate vent above any door or window, condensate can freeze causing ice formations. [1] Forced air inlet Do not use chimney as a raceway if another boiler or fireplace is vented [2] Gravity air inlet into or through chimney.
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Installation | 27 Pipe diameter per boiler Standard Material Item Standard [USA] [Canada] PVC schedule 40, Flue gas or 3” (80mm) 3” (80mm) ANSI/ASTM D1785 4” (100mm) combustion air 4” (100mm) 4” (100mm) Flue gas or 3” (80mm) PVC-DWV ANSI/ASTM D2665 4”...
The maximum length for vent and combustion air pipes can be found in SSB255 = 100 ft. (30 m) - 16 ft. (4.8m) = 84 ft. (25.60 m) each for the the following table. Please note the length is for each vent / combustion intake and exhaust piping.
Installation | 29 4 .7 .5 Approved examples of horizontal and vertical venting installation Place pipe supports every 5 feet (1,525 mm) of horizontal and vertical run, beginning with support near boiler. • The condensate must be disposed of in accordance with applicable rules. •...
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30 | Installation Fig. 32 Horizontal venting system (sealed combustion); X≥4” (102 mm); Y ≥12” (305 mm) Fig. 34 Vertical venting system (sealed combustion); X > 12” ; Y 12” above maximum snow level or at least 24” whichever is greater Fig.
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Installation | 31 Fig. 38 Horizontal concentric system (sealed combustion) Fig. 36 Horizontal venting system (sealed combustion) ; 3 is a wall termination Fig. 37 Horizontal venting system (sealed combustion); X≥4” (102 mm) Fig. 39 Vertical venting system (sealed combustion) ; ); X > 12” (305 mm);...
32 | Installation 4 .7 .6 Multiple boiler When installing multiple air and vent terminations, be sure that: • The clearance between the vent and air termination are in accordance with the figures shown in this chapter • All vent pipes and air inlet must terminate at the same height Fig.
(*) To calculate the de-rating of the input capacity follow this example: ► We have a SSB255 boiler installed at 5400 ft with a 3” flue system. The equivalent length of the vent pipe installed is 55 ft. The equivalent Air intake length of the air combustion pipe installed is 35 ft.
34 | Commissioning (for single boiler application) 5 .2 Setting date and time Commissioning (for single boiler application) Press the “menu” button and select “Settings” using the UP/DOWN button. Menu Domestic Hot Water Information Settings System Test Fig. 50 Press the “OK” button and select “General Settings” using the UP/DOWN button.
Commissioning (for single boiler application) | 35 Entering in “Time Zone Settings” menu it is possible to set the time zone parameter as shown in the following figure: CH setpoint cannot be changed when outdoor reset function is enabled. See section “5.5 Parameters list” for detailed instructions regarding outdoor reset.
36 | Commissioning (for single boiler application) 5 .6 Outdoor reset • State • Error To set the outdoor reset curve enter in “Central Heating (CH)” menu and press “OK”. The display shows four lines at a time: The display will appear as follow: Boiler Status Outdoor reset Flow Temperature...
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Commissioning (for single boiler application) | 37 Below is a list of parameters: Number Description Unit Default Step CH Setpoint °C / °F 176 °F 68 °F 194 °F 0.9 °F Design Supply Temp °C / °F 176 °F 68 °F 194 °F 1.8 °F Baseline Supply Temp...
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38 | Commissioning (for single boiler application) Number Description Unit Default Step Fan Speed Minimum Fan Speed Ignition Appliance Model ** Gas Type Flue length range Tab. 15 Level 2 parameters (*) Depend on appliance type (**) The value for this parameter is: •...
The “Test Status” switches to “on” and in the display will appear the fan speed. Wait 2 or 3 minutes to to reach steady state conditions and record the CO2 value. To adjust the CO2 value at the maximum power turn the screw “A” shown in Fig. 69 (for SSB255) and in Fig. 70 (for SSB399 and SSB512), allen type wrench is necessary for this adjustment.
Number of turns from gas Number of turns from gas 6 .1 Error codes are shown on the display valve fully wound home valve fully wound home SSB255 10 turns 2 and ¼ turns If the symbol appears on the screen as follow: SSB399...
Troubleshooting | 41 6 .1 .1 Lockout errors If an error is a “Lockout” error, it is necessary to press “RESET” button (after eliminating the reason for the failure) to restart the boiler. In the following table the “Lockout” errors are listed: Error Int .
42 | Troubleshooting Error Int . nr . Description Checks Solutions a- Check the integrity of Three times flame lost during one the wire connections of the a- If wires are damaged, replace "Too Many Flame Failures" demand spark and the earth on heat them exchanger "Flow Switch Not Closed Error"...
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Troubleshooting | 43 Error Int . nr . Description Checks Solutions a- Change the pump or restart it a- Check the pump to verify b- Open the valves on hydraulic the flow circulation circuit b- Check if the valves on “Overheat Error”...
44 | Troubleshooting 6 .2 Errors not shown on display Symptoms Possible solutions Check gas type. Combustion noise too loud; rumbling noises Check inlet gas pressure; adjust as needed. Check flue gas system; clean or repair as needed. Check gas/air ratio in the combustion air and flue gas; replace gas valve as needed. Set pump speed correctly to match maximum output.
Maintenance | 45 Time interval Maintenance Maintenance Annually * Verify startup Annually * Verify the flame 7 .1 General Annually * Check relief valve Annually * Inspect the burner gasket NOTICE: The installer must inform the user about the (*) Annually or every 2000 hours. Which occurs first. contents of this section.
46 | Applications The following system diagrams are showing primary/secondary piping. As Applications alternative a appropriate sized low loss header can also be used. When using primary/secondary piping please follow the following guidelines: The following shows possible system diagrams. Secondary Secondary NOTICE: Application drawings in this manual are Supply...
Applications | 47 Wiring diagram for multiple zone with indirect tank (pump for each zone): Boiler Pump CH Pump DHW CASCADE DHW Tank Room Supply 120 V Main in Alarm 120 V Aux Pump LINK Switch Door Sensor Thermostat Sensor 3 Way 1 2 3 4 5 6 7 8 9 10 11 12 13 14 101 102 103 104 105 106 107 108 109...
48 | Applications 8 .2 Multiple zone with indirect tank (valve for each zone) Purge Drain Zone relay Outdoor air sensor (optional) Pressure By-pass Heating zone Auto-Fill Eliminator Flow Check Condensate drain Room Thermostat Expansion Tank Relief valve pressure gauge Back-flow preventer Isolation...
Applications | 49 Wiring diagram for multiple zone with indirect tank (valve for each zone): Boiler Pump CH Pump DHW CASCADE DHW Tank Room Supply 120 V Main in Alarm 120 V Aux Pump LINK Switch Door Sensor Thermostat Sensor 3 Way 1 2 3 4 5 6 7 8 9 10 11 12 13 14 101 102 103 104 105 106 107 108 109...
50 | Applications 8 .3 Cascade connection Each cascade boiler has to be identified by an address (parameter N° 73 “Boiler Address” )different from the others. To define these address follow The SSB boilers can be connected together to form a cascade with a the steps below: maximum of 16 boilers.
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Applications | 51 A recommended scheme for cascade installation is as follow: Purge Drain Indirect Heating Tank Heating Indirect (optional) zone Return Outdoor air return sensor Auto-Fill Eliminator Indirect tank sensor (tank not shown) Condensate drain Room Thermostat Expansion Tank Relief valve pressure gauge...
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52 | Applications For this installation the wiring is shown in figure below: Pump DHW Boiler Pump CH CASCADE DHW Tank Room Supply 120 V Main in Alarm 120 V Aux Pump LINK Switch Door Sensor Thermostat Sensor 3 Way 1 2 3 4 5 6 7 8 9 10 11 12 13 14 101 102 103 104 105 106 107 108 109 110 111 112...
Applications | 53 8 .3 .1 Settings (*) NOTICE: The maximum amp load for each pump is 1 A Set the parameters as indicated in the following table (for the parameter when 2 or 3 pumps are connected. For this reason, if the list see section “5.5 Parameters list”): power consumption of each pump is higher than 84 watt, No .
54 | Commissioning log for the appliance Commissioning log for the appliance Please complete a separate log for each appliance. Home owner/operator: Last name, first name Number, Street Telephone/fax ZIP code, town System installer: Order number: Appliance type FD (Date of manufacture): Date commissioned: �...
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Commissioning log for the appliance | 55 Modified service functions: (select the modified service functions and enter the values here). Example: Vent Length Parameter changed from 1 to 2 Heating control 850 MIN: Vent length setting (par.99 “Flue length range”) � 1 | � 2 | � 3 | � 4 Gas type setting (par 98 “Gas Type”) �...
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56 | Spare parts Spare parts Fig. 82 6720818454 (2016/02) US...
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Alignment pin front side panels ■ ■ ■ 7-738-004-924 Alignment pin top panels ■ ■ ■ 7-738-004-925 Receiver alignment pin front panel ■ ■ ■ 7-738-004-945 Logo Bosch Front door ■ ■ ■ 7-738-005-176 Logo Buderus SSB ■ ■ ■ 7-738-005-177 6720818454 (2016/02) US...
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58 | Spare parts Shown on Fig. 85 - Fig. 86 Fig. 83 6720818454 (2016/02) US...
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Spare parts | 59 Item (→ Fig. 83) Description Order number High limit sensor and screws ■ ■ ■ 7-738-004-926 LWCO probe ■ ■ ■ 7-738-004-927 LWCO adapter and O-ring ■ ■ ■ 7-738-004-928 O-ring LWCO adapter ■ ■ ■ 7-738-004-929 Universal temperature detector and washer ■...
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Spare parts | 61 Item (→ Fig. 84) Description Order number Enclosure user interface ■ ■ ■ 7-738-005-037 Circuit Board user interface ■ ■ ■ 7-738-005-038 Keypad ■ ■ ■ 7-738-005-039 Service plug cover ■ ■ ■ 7-738-005-040 On Off power switch ■...
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62 | Spare parts SSB255 ONLY Fig. 85 6720818454 (2016/02) US...
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66 | Spare parts Notes 6720818454 (2016/02) US...
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Spare parts | 67 Notes 6720818454 (2016/02) US...
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United States and Canada Bosch Thermotechnology Corp. 50 Wentworth Avenue Londonderry, NH 03053 Tel. 603-552-1100 Fax 603-965-7581 www.boschheatingandcooling.com U.S.A. Bosch Thermotechnology Corp. reserves the right to make changes without notice due to continuing engineering and technological advances.