Viessmann VITODENS 200 Start-Up And Service Instructions page 38

Troubleshooting
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.
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
38
Cause of fault
Fuse
Variable speed heating circuit
pump
Heating system type incorrectly
coded
Thermostatic radiator valves
Circulating pump
Flue gas system leaking
Cause of fault
Main power on/off switch
Power supply or boiler is not
electrically connected
Fuse F1
(located in the Power/Pump
Module)
Electrical connection(s) has/have
been made incorrectly.
Fuse F2A
(located in the Power/Pump
Module)
Corrective action
Check fuse (see page 43).
Check coding of heating circuit
pump (see page 52).
Check coding of heating
system type (see page 49).
Check thermostatic radiator
valves (see page 43).
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/250 V, slow
blow)
Ensure that
– connections , , and
20A
on the mother board
– connections ..., , and
20A
in the boiler junction box
are made correctly.
Replace fuse with the same type
and of same rating (T10A/250 V,
slow blow)