Viessmann VITODENS 200 Start-Up And Service Instructions page 33

Cause of fault
Short circuit – WS/RS remote control unit
Open circuit – WS/RS remote control unit or wrong
coding
Internal BUS fault
Open circuit – internal BUS connection
KM-BUS fault to Vitocom
Short circuit/open circuit – BUS connection to extension
kit for heating circuit with mixing valve
Sensor inputs are not read correctly.
Data points are not stored; internal fault VR20.
AD-converter of burner control unit defective;
internal fault LGM 29
Differential air pressure sensor / open circuit
Differential air pressure sensor / short circuit
Internal fault or fault with internal data protection
Fault in Dekamatik-HK heating circuit control unit
connected downstream
Error message to Vitocom communication unit
Error message extension kit for heating circuit with mixing
valve
Parameterization of burner control defective
Emergency operation LGM 29
Parameterization of burner control defective
Corrective action
Check WS/RS remote control unit (see page 44).
Check WS/RS remote control unit (see page 44).
Check proper system coding.
Verify connections X5.3 and X5.4 for mixing valve
(if applicable).
Check that circuit board VR20 is inserted properly and check
field supplied connections (by process of elimination if field supplied connections (by process of elimination if
required).
Check coding of LGM 29 component part.
Replace circuit board VR20 or circuit board of burner control
unit LGM 29 (see page 61).
Check connection to Vitocom or Vitocom defective.
Check connection of extension kit for heating circuit with
mixing valve (see page 25). Check coding for system
with a mixing valve. Mixing valve might be defective.
Set DIP switches to factory default setting. See symbols on
back of programming unit.
Check correct connection of sensors.
Check for damage on wiring harnesses.
Check whether circuit board VR20 is defective.
If required, replace circuit board VR20
Replace circuit board VR20
Replace burner control unit LGM 29
Check wiring, replace sensor.
Check wiring, replace sensor.
Reset burner control unit.
Check Dekamatik-HK heating circuit control unit connected
downstream and data transmission circuit. Check wiring con-
nections.
Check Vitocom communication unit.
Check coding for extension kit and the extension kit itself.
Check sensor of mixing valve.
Replace circuit board of burner control unit LGM 29
Check plug-in connection and circuit board VR20.
Replace circuit board VR20 if necessary.
Replace circuit board of burner control unit LGM 29
Troubleshooting
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