Viessmann LB1 - Page 44

44
Cause Measure
Time interval for filter change has expired.
■
Check outdoor air and extract air filters.
■
Clean both filters if required.
■
Replace both filters if required.
■
Reset the filter service indicator.
05. Outdoor air temp. sens.
■
Both fans are stopped.
■
Preheating coil is switched off.
■
Bypass blocked.
Cause Measure
Short circuit/lead break, outdoor air temperature sensor Check resistance value (NTC 10 kΩ) at connection
X7.1/X7.2 on the control PCB of the ventilation unit. Re-
place sensor if required: See installation and service in-
structions for the ventilation unit for the curve.
07 Extract air temp. sens.
Bypass blocked.
Cause Measure
Short circuit/lead break, extract air temperature sensor Check resistance value (NTC 10 kΩ) at connection
X17.1/X17.2 on the control PCB of the ventilation unit.
Replace sensor if required: See installation and service
instructions for the ventilation unit for the curve.
0A Humidity sensor
Bypass blocked.
Cause Measure
Signal capture from central humidity sensor is faulty. Check central humidity sensor. Isolate the ventilation
unit from the power supply. Replace humidity sensor if
required.
14 Supply air fan
■
Both fans are stopped.
■
Electric preheating coils are switched off.
Cause Measure
Supply air fan blockage, fault or signal interruption
■
Check fan for blockage or contamination. Remove
any blockages. Clean fan.
■
Check fan electrical connections and connecting ca-
ble.
■
Check fan is mechanically and electrically sound.
■
Replace fan if required.
15 Exhaust air fan
■
Both fans are stopped.
■
Electric preheating coils are switched off.
Troubleshooting
Message list Vitovent 300-C/300-W (cont.)
5816558
Diagnosis