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Bosch SSB120, Service Manual, Page: 5 / 48

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Bosch SSB120 Service Manual Download Page 5

SSB

6720866940 (2017/11) US

Product description | 5

2 .3 

Start/Stop cycle

Fig. 1  Burner ignition cycle diagram

False flame detection

If flame is detected at the end of the pre-spark period (Ignit_0) a lockout error occurs (This lockout has a maximum of 3 auto 

resets).

Re-ignition

If at the end of the safety period no flame is detected the control will go to post-purge to remove the unburned gas. After this a 

re-ignition attempt is started following the same cycle.

The number of re-ignition attempts is limited to Max_Ignit_Trials after which a lockout occurs.

Intermittent operation

The burner can only be ON continuously for a period of 24 hours.

After this the burner is switched OFF and a restart sequence follows.

Flame establishing time

Sparking stops Spark_Before_End_Of_Safety_Period seconds before the end of the Ignit_1 period to allow for ionization 

detection.

Flame out too late

If after Max_Post_Purge_0 time flame is still detected a lockout follows.

Safety relay test

In Safety ON/OFF state the correct working of the safety relay is proven.

Demand

Once the ignition sequence is started it will be finished*. Even if the demand is taken away during the ignition sequence the 

sequence up to the burn state is ended.

If during Burn_0 state the demand is taken away, a Post_Purge_Period follows at Post_Purge_Speed speed.

Tab. 1   

Summary of Contents for SSB120

Page 1: ...perating instructions are part of the technical documents that must be handed over to the owner or operator of the heating system Explain to the owner or operator how to use the heating system using the operating instructions Make sure that they are familiar with all required information for the safe and proper operation of the heating system These instructions are available in English and French ...

Page 2: ...tion 15 5 6 Parameters list 15 6 Parameters description 17 6 1 Central Heating CH 17 6 2 Domestic Hot Water 18 6 3 Pump mode and connections 20 7 Commisioning 21 7 1 First operation 21 7 2 Inlet Gas Pressure 21 7 3 Switching from NG to LPG 21 7 4 CO2 Setting 23 8 Maintenance schedule procedures 24 8 1 Gas Leak Inspection 24 8 2 Flue Combustion air piping inspection 24 8 3 Checking for Wiring and c...

Page 3: ...ollow the local state and federal installation regulations Risk of fatal injury from flue gas poisoning Insufficient ventilation or combustion air availability may cause dangerous flue gas leaks or formation Make sure that inlets and outlets are not reduced in size or closed If faults are not corrected immediately the boiler must not be operated until all faults have been corrected Inform the syst...

Page 4: ... boiler from the main power supply is forbidden Do not remove or modify safety equipment Do not pull or twist the electrical wires from the boiler even if the device is disconnected from the main power supply Do not obstruct or reduce the ventilation openings Do not put the unit outdoors Do not leave any combustibles or containers of flammable substances in the room where the boiler is installed D...

Page 5: ...tent operation The burner can only be ON continuously for a period of 24 hours After this the burner is switched OFF and a restart sequence follows Flame establishing time Sparking stops Spark_Before_End_Of_Safety_Period seconds before the end of the Ignit_1 period to allow for ionization detection Flame out too late If after Max_Post_Purge_0 time flame is still detected a lockout follows Safety r...

Page 6: ...ressure differential switch 2 Fan 3 Burner head 4 Spark electrode 5 Circulation pump 6 Condensate trap 7 Return temperature probe 8 Heat exchanger 9 Main controller 10 Automatic air vent 11 High limit temp safety switch 12 Supply temperature probe 13 Gas valve 14 Low water cut off probe 3 Boiler components ...

Page 7: ...f Valve 8 Tridicator 9 Low water cut off probe 10 Heat exchanger supply pipe 11 Fan 12 Gas valve 13 Automatic air vent 14 Supply temperature probe 15 High limit temp safety switch 16 Heat exchanger 17 Condensate trap 18 Low point drain valve 19 Circulation pump 20 Return temperature probe 21 Wiring Control Panel 22 Spark electrode 23 Gas pipe 24 Removable display 25 Pressure differential switch 26...

Page 8: ... Fig 6 Burner head 4 2 Heat exchanger The heat exchanger Fig 7 is a single coil design made of stainless steel Fig 7 Heat exchanger Burner cross sectional view 4 3 Combustion chamber The cylindrical combustion chamber Fig 7 has a top and bottom steel ring bands that are removable for heat exchanger servicing 4 4 Ignition electrode The ignition electrode Fig 8 is a component inserted in the burner ...

Page 9: ...eturn temperature sensors The supply Fig 10 and return Fig 11 temperature sensors are immersion type NTC s rated 10KΩ at 25 C 77 F See Tab 12 for resistance values for NTC sensor The supply sensor is located at the outlet of the heat exchanger the return temperature sensor is located at the inlet of the heat exchanger Supply temperature sensor Fig 10 Supply temperature sensors Return temperature s...

Page 10: ...ad The fan has an integrated PWM speed control Fig 14 Fan 4 10 Gas valve The proportional gas valve Fig 15 Fig 16 is located above the fan and it s connected to the Venturi The gas valve has 2 safety solenoid valves The gas valve regulates the air fuel ratio on the basis of combustion air delivery the air fuel ratio is 1 1 Fig 15 Gas valve SSB85 SSB120 gas valve Fig 16 Gas valve SSB160 4 11 Ventur...

Page 11: ...ssure switch is a safety device designed to turn off the burner in case of block vent for example due to obstruction of condensate drain The silicon pipe is connected on one end to the port of pressure switch Fig 20 and on the other end to the bottom of the heat exchanger Fig 21 Fig 20 Flue pressure switch Inch W C mbar 1 4 3 5 Tab 3 Flue gas pressure switch setpoint value Connection on the bottom...

Page 12: ...The 3 4 discharge outlet must be piped per local code requirements Boiler model Pressure value SSB85 30 psi 2 07 bar SSB120 30 psi 2 07 bar SSB160 30 psi 2 07 bar Tab 4 Max Setpoint values of relief valve Fig 22 Pressure relief valve pipe connection from boiler supply to relief valve is field supplied and does not come with the boiler ...

Page 13: ...nsor is connected On the right the set setpoint 2 value is shown The top right corner shows the time 3 5 2 Date and time setting Press the menu button and select Settings using the arrow buttons to select Settings Menu Domestic Hot Water Information Settings System Test Fig 25 Press the OK button and select General Settings using the arrow buttons Settings General Settings Boiler Settings Fig 26 P...

Page 14: ...mestic Hot Water Information Settings Fig 32 Menu Central Heating Domestic Hot Water Information Settings Fig 33 CH and the DHW setpoint can be edit directly from the homepage of the display When the text on the bottom left side is CH Setpoint press the right button The value shown in the bottom right side will be highlighted using the UP DOWN keys it is possible to change the value Once assigned ...

Page 15: ...80 F Bas Supply T 104 F WW Shutdown 70 F Bas Outd T 70 F T_Outside F Des Outd T 25 F Fig 38 Des Supply T and Des Outd T will be highlighted to change either value press OK Use UP DOWN arrows to change the Des Supply T Use the LEFT RIGHT arrows to change the Des Outd T Press OK to save changes Use the LEFT RIGHT arrows to select the other values Repeat steps to make additional changes Once set the ...

Page 16: ...y Max Limit C F 194 F 80 6 F 194 F 1 8 F 25 Warm Weather Shutdn C F 69 8 F 35 6 F 95 F 1 8 F 26 Boost Temp Increment C F 0 F 0 F 54 F 0 9 F 27 Boost Time Delay Minutes 20 1 120 1 28 Night Setback Temp C F 18 F 0 F 90 F 0 9 F 29 Weather Setpoint C F 68 F 32 F 122 F 0 9 F 35 DHW Mode 0 0 2 1 36 DHW Tank Hyst Down C F 7 2 F 0 F 36 F 0 9 F 37 DHW Tank Hyt Up C F 0 F 0 F 36 F 1 8 F 38 DHW Tank Supply E...

Page 17: ...and Room thermostat If the parameter CH_Mode is set to 1 Outdoor temperature reset with room thermostat mode is selected This mode will only function when an outdoor temperature sensor is connected but default setting can be customer specific for production series If the outdoor sensor is connected the boiler automatically uses the Max Supply Temp The setpoint is calculated depending on the outdoo...

Page 18: ... 6 2 Domestic Hot Water Par 35 DHW_Mode Mode 0 No Domestic Hot Water Mode 1 External DHW tank with temperature probe In this Mode 1 DHW is produced by heating a domestic indirect tank Either a DHW pump or 3 way valve can be used to switch to DHW mode The DHW temperature in the tank is measured with a sensor T_Store and set with parameter DHW_Store_Setpoint When this sensor drops below DHW_Store_Se...

Page 19: ...ture of the DHW tank by maintaining the burner at minimum firing rate The default temperature is 3 6 F 2 C Par 43 DHW Max Priority Time Imposes a timelimit for DHW priority and CH Par 44 DHW Pump Overrun Time Sets the delay off for DHW pump Par 91 DHW max Setpoint Sets the temperature limit for the DHW tank Mode 2 DHW tank with thermostat control dry contact In DHW_Mode 2 DHW is prepared by warmin...

Page 20: ...inal DHW PUMP T_store CH supply out in DHW CH return CH PUMP Primary Heat Exchanger DHW_mode 1 DHW PUMP DHW_stat CH supply out in DHW CH return CH PUMP Primary Heat Exchanger DHW_mode 2 CH supply CH return CH PUMP T_return T_flue T_supply Safety Limit Primary Heat Exchanger DHW_mode 0 Ch only CHW PUMP L J6 1 J6 3 J6 2 J7 1 N L PE Fig 44 Pump mode 1 Boiler with one primary pump and 3 way valve for ...

Page 21: ...omponents were removed or tampered with 10 Fill the condensate trap with water and ensure a continuous downward slope exists in the outlet tube Only after verifying steps 1 to 10 should commissioning of the boiler be performed 7 2 Inlet Gas Pressure It is necessary to check the gas pressure at the inlet of the gas valve remains steady With the burner operating the inlet gas pressure should not dec...

Page 22: ...ust the CO2 level according to the values shown in Tab 9 Boiler Model SSB160 In Fig 52 The components indicated must be disassembled to access the LPG orifice installation location Gas fitting Fig 52 Gas fitting model SSB160 Separate the Venturi from the gas valve to access the orifice installation location Fastener to be removed Fig 53 Installation location for the LPG orifice model SSB160 Ventur...

Page 23: ... 4 Select High Power using the up down arrow keys The burner will start and run at maximum rpm Adjust the CO2 value until it is between the range reported in table 7 To increase the CO2 turn the proportional control screw A Fig 46 Fig 47 counter clockwise all models System Test Test State High Power Fan Speed 0 rpm Ionisation 0 0 μA Fig 58 System test menu 5 Select Low Power using the up down arro...

Page 24: ...ondensate discharge Annually Safety block check modulation range check gas valve closing after burner stop Annually Check control parameters Annually Check for gas piping leak Annually Check wiring and connection Annually Verify startup Annually Verify the flame Annually Check relief valve Annually Inspect the burner gasket Annually or every 2000 hours Which occurs first Tab 11 Licensed contractor...

Page 25: ...hose Fig 64 Air inlet hose SSB160 3 Close the manual gas valve upstream to the boiler and then disconnect the fitting on gas pipe as follows Gas fitting Fig 65 Gas fitting SSB85 SSB120 Gas fitting Fig 66 Gas fitting SSB160 4 Remove the fan unscrewing the 4 nuts that fix it to the heat exchanger see picture below showing 3 out of 4 nuts A Fig 67 Fan 4 nuts 5 Remove the fan Fan Fig 68 Fan ...

Page 26: ...e interior surface of the heat exchanger Carefully perform all steps below 1 To access the combustion chamber repeat the burner head removal process then proceed to step 2 2 Unscrew bolt A partially open the clamp B fastening the top cap to the heat exchanger body A B Fig 71 Clamp fastening 3 Remove the exchanger top cap including the insulation Top cap insulation Fig 72 Exchange top cap 4 The ope...

Page 27: ... 76 Brush remove debris 9 Apply the CLEAN F9A decalcifier using the manual spray bottle and let stand for 10 minimum to 20 maximum minutes 10 Rinse the heat exchanger using water and the manual water pump Care should be taken to avoid flooding the heat exchanger If the tubes are heavily obstructed repeat the cleaning and rinsing process 11 Remove the calorite protection disc and reassemble the top...

Page 28: ...7 Inspection replacement and features of supply return and flue NTC temperature sensors The NTC sensor transduces a temperature value into an electrical resistance The characteristics of NTC sensor are reported on Tab 12 below The supply return and flue temperature sensors are immersion type and have the same electrical characteristic 10 kΩ at 25 C To remove and replace the NTC probes turn off the...

Page 29: ...al supply 9 1 Electrical supply wiring Connect the boiler to the main electrical supply as required by local state and federal codes The power supply cables can be inserted into the boiler using one of the three knock out holes A located on each side of the cabinet A Fig 84 Knock out holes 9 2 Access to the electrical terminal strip To have access to the internal terminal strip of the boiler follo...

Page 30: ...t the room thermostat to terminals 11 12 9 5 DHW tank sensor connection Connect the DHW tank sensor to terminals 9 10 9 6 Outdoor temperature sensor If outside temperature control is to be used the outside probe needs to be connected to terminals 7 8 The probe shall be installed on an outer wall North or North East away from windows doors and ventilation grids Never install the probe in a position...

Page 31: ...blu GND Ther mostat Manual Reset Switch Normally Closed Opens to Reset Alternate Chassis Ground Connection External Test Switch Normally Closed Opens to Test RESET GND AC COMMON TEST 24 VAC HOT PROBE P CHASSIS GROUND Via Boiler Piping AR1 AR1 120V 24V 210 210 210 208 208 208 209 209 209 214 214 214 HIGH VOLTAGE LOW VOLTAGE IN OUT HIGH Tank Sensor OUT DOOR MOD BUS GAS SWITCH 120 V MAIN IN Supply Se...

Page 32: ...or 11 Control had a blocking error for more than 20 hours in a row Press RESET button to display the Blocking error description Remove the cause of the Blocking error Fan Error 12 Fan MF deviation for more than 60 sec a Check for 120 Vac power connection of the fan b Check PWM connection of the fan a If no 120 VAC voltage is present replace the power control board b If no PWM signal is present rep...

Page 33: ...board Flame Error 2 54 Flame is detected in a state in which no flame is allowed to be seen Replace the power control board Water Level Detect 55 Low water level detected Water Level Meas 56 Low water level measurement error Low Water Cutoff Error 57 Low water sensor error Check the LWCO If the LWCO is in alarm try to reset it Low Water Pressure Error 58 Low water pressure error Low Water Pressure...

Page 34: ...connections b Check the supply temperature sensor a If the wiring is damaged replace it b Verify that the temperature sensor has the correct resistance values If values are incorrect sensor must be replaced T Return Shorted 81 Return sensor shorted a Check the integrity of the wire connections b Check the return temperature sensor a If the wiring is damaged replace it b Verify that the temperature...

Page 35: ...Heating up takes too long Set pump speed correctly to match maximum output Set pump mode Flue gas readings incorrect CO levels too high Check gas type Check inlet gas pressure adjust as needed Check flue gas system clean or repair as needed Check gas air ratio in flue gas replace gas valve as needed Hard ignition poor ignition Check gas type Check inlet gas pressure adjust as needed Check power su...

Page 36: ...6720866940 2017 11 US SSB 36 Spare parts 10 Spare parts 13 4 12 10 3 9 16 9 14 13 5 6 13 7 2 1 15 14 11 11 13 8 Fig 88 ...

Page 37: ...ront 7 738 004 923 5 Panel top front 7 738 005 116 6 Panel top rear 7 738 005 117 7 Cover control board 7 738 004 907 8 Mounting bracket control board panel 7 738 004 908 9 Alignment pin front side panels 7 738 004 924 10 Logo Bosch front door 7 738 005 176 11 Handle front panel 7 738 004 920 12 Lock and lever front panel 7 738 004 921 13 Alignment pin front panel 7 738 004 944 14 Receiver alignme...

Page 38: ...6720866940 2017 11 US SSB 38 Spare parts 15 26 23 19 20 5 22 11 10 7 9 22 21 18 17 15 16 32 14 13 12 31 30 29 15 24 25 26 7 3 2 5 6 1 4 32 10 27 28 33 33 34 35 Shown on Fig 91 Fig 92 Fig 89 ...

Page 39: ...0 18 Condensate discharge pipe 0 71in 18mm 7 738 005 126 19 Boiler Return pipe 0 79in 20mm 7 738 005 144 19 Boiler Return pipe 0 79in 20mm 7 738 005 145 20 Pump return pipe 7 738 005 389 20 Pump return pipe 7 738 005 390 21 Pump UPS15 58 7 738 005 134 21 Pump UPS25 78 7 738 005 391 22 Adapter 1 1 2 F 1 M 7 738 005 392 23 PP boiler combustion pipe 1 97in 50mm 7 738 005 148 23 PP boiler combustion p...

Page 40: ...6720866940 2017 11 US SSB 40 Spare parts 6 75 6 5 4 6 5 3 2 1 7 8 9 10 16 15 18 17 14 13 12 11 21 20 23 24 25 19 Fig 90 ...

Page 41: ... Control Board 7 738 005 046 11 Transformer 24V 0 6 amps 7 738 005 047 12 LWCO circuit board 7 738 005 048 13 Fuse carrier 7 738 005 049 14 Red LED light 7 738 005 050 15 Fuse 6 A 7 738 005 051 16 Fuse 0 125 A 7 738 005 052 17 Test push button 7 738 005 053 18 Manual reset push button 7 738 005 054 19 Wiring harness 7 738 005 151 19 Wiring harness 7 738 005 153 20 Outdoor sensor 10 k ohm 7 738 005...

Page 42: ...6720866940 2017 11 US SSB 42 Spare parts SSB85 SSB120 18 17 12 13 13 14 16 12 11 10 19 20 9 7 5 6 4 8 3 2 1 21 Fig 91 ...

Page 43: ...e 7 738 005 399 7 Burner flange inner ring 7 738 005 400 8 Gasket burner flange inner ring to fan 7 738 004 990 9 Fan Venturi 7 738 005 159 10 Gasket venturi tube gas valve SSB85 120 7 738 005 409 11 Gas valve and washers 7 738 005 160 12 Washer gas pipe 3 4 19 05mm 7 738 005 023 13 Circular clamp 1 97in 50mm 7 738 005 015 14 Flexible pipe air intake 7 738 005 166 16 Gas pipe 7 738 005 414 17 Fram...

Page 44: ...6720866940 2017 11 US SSB 44 Spare parts SSB160 ONLY 13 13 15 12 11 6 1 2 3 4 7 5 8 9 10 17 17 19 20 18 14 16 22 21 23 Fig 92 ...

Page 45: ...er ring to fan 7 738 004 990 9 Fan 7 738 005 007 10 Gas valve and washers 7 738 005 009 11 Gasket venturi tube fan 7 738 004 950 12 Venturi 7 738 005 163 13 Circular clamp 1 97in 50mm 7 738 005 015 14 Venturi tube gas valve washer 7 738 005 011 15 Flexible pipe air intake 7 738 005 167 16 90 PP air intake elbow 7 738 005 404 17 Washer gas pipe 3 4 19 05mm 7 738 005 023 18 Gas pipe 7 738 005 171 19...

Page 46: ...6720866940 2017 11 US SSB 46 Spare parts Notes ...

Page 47: ...SSB 6720866940 2017 11 US Spare parts 47 ...

Page 48: ...echnology 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 ...

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