Viessmann VITOTRONIC 200 Service Instructions Manual page 53

Messages
(cont.)
Message
Code/system characteris-
tics
AE Cyl. sensor top/bottom
–
AF Cylinder primary pump
Inadequate change of
temperature in the DHW
cylinder.
B0 Device recognition
Heat pump does not
start.
Cause
Top and bottom temper-
ature sensors swapped
in the DHW cylinder.
■ Circulation pump for
cylinder heating faulty.
■ Circulation volume in
primary store system
too low; cylinder pri-
mary pump or 2-way
valve on primary store
system faulty.
Error in recognising
appliance version, incor-
rect coding card or PCBs
faulty.
Troubleshooting
Measures
No measures required.
Heat pump control unit
interchanges the sensors
internally.
■ Circulation pump for cyl-
inder heating:
Check voltage at termi-
nal 211.4 (see
page 150) and check
pump mechanically;
replace if required.
■ Cylinder primary pump/
2-way valve:
Check voltage at termi-
nal 224.6 (see
page 155) and check
pump/valve mechani-
cally; replace if
required.
■ Check sensor input F11
on controller and sensor
PCB (see page 172).
No connection should
be made at terminal
F11.
■ Check coding card (see
page 172); replace if
required.
■ Check PCBs and
replace if required.
Note
After removing fault,
switch appliance OFF and
ON again once.
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