Viessmann Vitocrossal 300 CA3 2.5 Installation And Service Instructions Manual page 182

Troubleshooting
Boiler System Fault Codes
Displayed System characteristics
fault code
c9 Boiler cools down.
cA Boiler cools down.
cB Boiler cools down.
cF Control mode
No communication via LON,
boiler at a configurable
temperature set point
d1 Boiler cools down.
d2 Control mode
d3 Control mode
d4 Boiler cools down
d5 Boiler ramps up to the electronic
maximum boiler water
temperature limit.
d6 Control mode
d7 Control mode
d8 Control mode
da Control mode without room
influence.
db Control mode without
room influence
182
Vitocrossal 300 CA3 Series 2.5 to 6.0 Installation/Service
(continued)
Cause
Fault, maximum pressure limiter
at "X3" of plug-in adapter 1 for
external safety equipment
Fault, minimum pressure limiter
or maximum pressure limiter 2
at "X2" of plug-in adapter 1 for
external safety equipment
Fault at additional safety
temperature limiter or
temperature monitor at "X1" of
plug-in adapter 1 for external
safety equipment
Communication error, control
unit LON communication module.
Burner in fault mode
Communication fault, Plug-in
adapter 2 for external safety
equipment
Communication error, extension
EA1.
MCB F2 has responded.
Connection plug aBA broken.
No communication between
boiler circuit control unit and
cascade control unit.
Input DE1 at extension EA1
reports a fault.
Input DE2 at extension EA1
reports a fault.
Input DE3 at extension EA1
reports a fault.
Short circuit, room temperature
sensor, heating circuit without
mixing valve A1 (heating circuit 1).
Short circuit, room temperature
sensor, heating circuit with mixing
valve M2 (heating circuit 2).
Measures
Check system pressure,
reset maximum pressure limiter.
Check system pressure,
reset minimum pressure limiter
or maximum pressure limiter 2.
Check system temperature,
reset safety temperature limiter.
Check LON communication
module and replace if required.
If no LON communication module
is installed, set code "76:0" in
the "General" group.
Check burner
Check plug-in adapter , if no
plug-in adapter is available,
adjust coding "31:0" in
"General" group.
Check connections (see page
36). Without extension EA1:
Set code "5b:0" in the
"General" group.
Check MCB F2 and jumper on
plug aBA.
Fuse F2 has tripped or check
connection to Plug aBA, possibly
plug aBA not inserted.
Check communication via
participants check.
Check configuration of cascade
participants.
Remove fault at appliance
concerned.
Remove fault at appliance
concerned.
Remove fault at appliance
concerned.
Check room temperature
sensor (see page 186).
Check room temperature
sensor (see page 186).