Viessmann VITODENS 200 Start-Up/Service Instructions page 33

Vitodens 200 WB2 Service
Diagnosis
(continued)
Diagnostics table: Faults without fault display on control unit
System behavior
Supply temperature too cold or too warm.
Room temperature too cold or too warm. Thermostatic radiator valves
Domestic hot water temperature too
cold or too warm.
Boiler constantly switches on and off.
Diagnostics table: Faults on power module
System behavior
Boiler has no power
(Main power on/off switch on boiler
is in "ON" position).
Heating pump does not operate
(only with expansion board installed).
Cause of Fault
Fuse
Variable speed heating circuit pump Check coding of heating circuit pump
Heating system type incorrectly coded Check coding of heating system type
Circulating pump
Flue gas system leaking
Cause of Fault
Main power on/off switch
Power supply or boiler is
not electrically connected.
Fuse F1
Electrical connection(s)
has/have been made
incorrectly.
Fuse F2A
Corrective action
Check fuse (see page 38).
Check thermostatic radiator valves
(see page 38).
Check circulating pump.
Check flue gas system for leaks and
perform leak test.
Corrective action
Check switch position.
Ensure that power cord and power supply
cable to the boiler are plugged in properly.
Replace fuse with same type and of same
rating (T2A/250V, slow blow).
Ensure that
– connections 20, 20A,21 and on the mother
board
– connections 20, 20A,21 and in the boiler
junction box are made correctly.
Replace fuse with the same type and of same
rating (T4A/250V, slow blow).
Troubleshooting
33