Viessmann B0KA Installation And Service Instructions Manual page 62

Troubleshooting
Fault messages
(cont.)
Displayed fault System characteristics
code
163 Burner in a fault state
182 No DHW heating
183 No DHW heating
184 Burner in a fault state
185 Burner in a fault state
345 Burner locked out, automatic
enabling after appliance cool-
down. Independent restart
346 Burner in a fault state
348 Burner in a fault state
62
Cause
Checksum error, data
memory access, HBMU
heat management unit
Short circuit, outlet tem-
perature sensor (if instal-
led)
Lead break, outlet temper-
ature sensor (if installed)
Short circuit, flow temper-
ature sensor/high limit
safety cut-out
Lead break, flow tempera-
ture sensor/high limit safe-
ty cut-out
Temperature limiter has
responded.
Ionisation current calibra-
tion error
Gas modulation valve
Measures
Reset the appliance.
If the fault occurs repeatedly, re-
place the HBMU heat management
unit. See chapter "Replacing the
HBMU heat management unit".
Check outlet temperature sensor
(plug X7, cores 3 and 4). Measure
sensor input on HBMU heat man-
agement unit. Set value: 3.3 V
with sensor disconnected
Check outlet temperature sensor
(plug X7, cores 3 and 4).
Check the flow temperature sen-
sor/high limit safety cut-out.
Check sensor lead. Replace faulty
component if required.
Reset the appliance.
Check the flow temperature sen-
sor/high limit safety cut-out. Re-
place faulty component if required.
Reset the appliance.
Ensure adequate heat transfer.
■
Check heating system fill level.
■
Check pre-charge pressure in di-
■
aphragm expansion vessel. Ad-
just to required system pressure.
Check whether flow rate is suffi-
■
cient (pump).
Check function of 3-way diverter
■
valve. Vent the system.
If the fault occurs during DHW
heating: Check the DHW cylinder
or plate heat exchanger for dirt and
scaling.
Check the gas supply pressure.
■
Check gas solenoid valve inlet
■
strainer for dirt.
Check ionisation electrode for
■
contamination.
Check flue system. Remove flue
■
gas recirculation if required.
Check the condensate drain
■
(condensate blockage).
Reset the appliance.
If several heat generators are con-
nected to a common flue system:
Check whether "Multiple connec-
tion" is set in the commissioning
assistant.
Check the flue system for unre-
stricted flow.
If fault remains, replace gas fan
unit.
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