Bosch SSB255 Installation And Service Manual page 43

Error
"Overheat Error"
"T Supply Open"
"T Return Open"
"T Dhw Out Open"
"T Supply Shorted"
"T Return Shorted"
"T Dhw Out Shorted"
"T Flue Shorted"
"Reset Button Error"
"Appliance Selection"
"Gas Pressure Error"
"Flue Press Error"
Tab. 19 Blocking errors
SSB
Int . nr . Description
70 Supply temp exceed the limit
72 Supply sensor open
73 Return sensor open
76 DHW sensor open
80 Supply sensor shorted
81 Return sensor shorted
84 DHW sensor shorted
86 Flue sensor shorted
87 Reset button error
93 Appliance selection error
107 Gas pressure too low or too high
108 Flue gas pressure error
Checks
a- Check the pump to verify
the flow circulation
b- Check if the valves on
c- Verify that the temperature sensor
hydraulic circuit are open
has the correct resistance values. If
c- Check the supply
values are incorrect sensor must be
temperature sensor
a- If the wiring is damaged, replace
a- Check the integrity of the
wire connections
b- Check the supply sensor has the correct resistance
temperature sensor
a- If the wiring is damaged, replace
a- Check the integrity of the
wire connections
b- Check the return sensor has the correct resistance
temperature sensor
a- If the wiring is damaged, replace
a- Check the integrity of the
wire connections
b- Check the DHW sensor has the correct resistance
temperature sensor
a- If the wiring is damaged, replace
a- Check the integrity of the
wire connections
b- Check the supply sensor has the correct resistance
temperature sensor
a- If the wiring is damaged, replace
a- Check the integrity of the
wire connections
b- Check the return sensor has the correct resistance
temperature sensor
a- If the wiring is damaged, replace
a- Check the integrity of the
wire connections
b- Check the DHW sensor has the correct resistance
temperature sensor
a- If the wiring is damaged, replace
a- Check the integrity of the
wire connections
b- Check the flue temperature sensor has the correct resistance
sensor
Too many reset button
pushes in a 60 sec period
Replace the power control board
a- Remove any obstructions from
a- Check for any obstruction
in the exhaust system
b- Check the condensate
condensate discharge and verify if
discharge
Troubleshooting | 43
Solutions
a- Change the pump or restart it
b- Open the valves on hydraulic
circuit
replaced.
it
b- Verify that the temperature
values. If values are incorrect
sensor must be replaced.
it
b- Verify that the temperature
values. If values are incorrect
sensor must be replaced.
it
b- Verify that the temperature
values. If values are incorrect
sensor must be replaced.
it
b- Verify that the temperature
values. If values are incorrect
sensor must be replaced.
it
b- Verify that the temperature
values. If values are incorrect
sensor must be replaced.
it
b- Verify that the temperature
values. If values are incorrect
sensor must be replaced.
it
b- Verify that the temperature
values. If values are incorrect
sensor must be replaced.
the exhaust system
b- Remove any obstruction from
the condensate can flow freely
6720818454 (2016/02) US