Viessmann VITODENS 200 Start-Up And Service Instructions page 37

Cause of fault
Emissions test switch "S" turned to "h" for 30 minutes
already.
Setting mode for maximum or minimum rated input active
for 30 minutes already.
Reset button "EU" pressed while burner is off with emis-
sions test switch "S" turned to "h".
Basic level of air pressure threshold in standby mode not
correct.
Start-up prevented.
DHW outlet sensor / short circuit
DHW outlet sensor / open circuit
Corrective action
Turn emissions test switch "S" to "a".
Set heating program selector switch to required operating
mode or close cover on programming unit.
Turn emissions test switch "S" to "a" and press reset
button "EU" once.
Check differential air pressure sensor (see page 41).
Check wiring harness and connection to air pressure sensor.
Fault will clear if output signal of air pressure sensor is
correct.
Check wiring, water and gas pressures.
Check sensor/wiring.
See coding address "000" (page 49).
See coding address "0B8" (page 54).
Check sensor/wiring.
See coding address "000" (page 49).
See coding address "0B8" (page 54).
Troubleshooting
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